Download dasar ilmu tanah

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Kapasitas organisme hidup dalam tanah
(mikroorganisme, fauna dan akar) untuk berkontribusi
dalam ketersediaan/penyediaan unsur hara bagi
tanaman, sambil memelihara proses-proses biologis
yang dapat memperbaiki sifat fisika dan kimia tanah.
Jaring-jaring Makanan Tanah
Trofik tingkat
pertama
Fotosintesis
Trofik tingkat ke
dua:
Dekomposer
Mutualis
Patogen, Parasit,
Pemakan akar
Trofik tingkat ke
tiga:
Predator
Grazers
Shreder
Trofik tingkat
ke empat:
Predator
tingkat tinggi
Trofik tingkat ke
lima atau lebih:
Predator tingkat
tinggi
Organisme tanah terlibat dalam setiap aspek kualitas tanah
Struktur / Agregasi
Bahan
Organik
Humifikasi
Komunitas
Tanah
Pencucian
Nitrat
Dekomposisi
Siklus Hara
Untuk memahami bagaimana biologi mempengaruhi tanah – kita
perlu mempelajari organisme yg hidup dalam tanah
ORGANISME TANAH
FAUNA
MAKRO
SERANGGA
RAYAP
BEKICOT
CACING
FLORA
MIKRO
NEMATODA
ROFIFERA
PROTOZOA
MIKRO
BAKTERI
AKTINOMISETES
CENDAWAN
GANGGANG/ALGAE
Tanah sebagai Habitat
Akar
tumbuhan
Partikel tanah
Air
Tanah memang hidup …….…
Misalnya, dalam 1g tanah:
>100,000,000 sel bakteri
>11,000 species bakteria
Juga fungi dan binatang yg lebih besar
POPULASI makro-organisme dalam TANAH SUBUR
Flora dan Fauna Mikro
Bakteri
Aktinimesetes
Cendawan
Ganggang
Protozoa (mikro fauna)
Fauna Tanah
Cacing tanah
gastropoda
Kaki Seribu (melipede)
Kaki Seratus (centipede)
Kutu (mite)
Juta/gram
1 – 100
0,1 – 1
0,01 – 1
0,01 – 0,1
0,01 – 0.1
Juta/ha
1,8
1,0
1,8
0,8
44,1
Siapa di situ ?
Makrofauna:
‘Engineer’ tanah
Binatang Tanah
Pseudoscorpion
Termite
Earthworm
Centipede
Snail
Vole
Binatang tanah penting untuk:
1. Dekomposisi (mencacah
residu seresah)
2. Pencampuran tanah (aerasi)
Laju dekomposisi blue grama (Bouteloua gracilis)
Siapa di situ?
Mesofauna:
Predator tanah,
Pathogen,
Herbivora.
Meso Fauna
Nematodes
Mites
Meso-fauna tanah penting untuk:
•
Dekomposisi residu tumbuhan
•
Predasi
•
Pathogenesis
Mikro-organisme:
Pengendali proses
Tanah
Mikro-organisme Tanah
Fungi
Bacteria
Fungi
Fungi
Pertumbuhan Filament
Apa keuntungan habit yang
filamentous?
Fungi
• Pertumbuhan Filament
• Fungsinya sngt penting
- Perusak kayu
- Asosiasi Mycorrhiza
• myco (fungus) + rhiza (root)
(Struktur simbiosis yg dibentuk
oleh fungi dan tumbuhan)
Akuisisi fosfat
oleh akar
Partikel tanah
Fosfat
Source: Harrison et al 1999
Akuisisi fosfat
oleh Mikorhiza
akar
Partikel tanah
Fosfat
Roots with mycorrhizae
Source: Harrison et al 1999
Bacteria
Kecil, bersel tunggal
~2µm
Bacteria
• Kecil, bersel tunggal
• Berlebihan
Conventional
tillage
Prairie
Bacteria
No-till
Fungi
Forest
Bacteria
1.
2.
3.
Kecil, bersel tunggal
Banyak jumlahnya
Beragam – secara
taksonomi dan secara
fungsional.
Diversitas dalam tanah sangat penting untuk siklus nitrogen.
Simpanan
Simpanan
Antropogenik
Antropogenik
Faktor mediasi
Alamiah
Simpanan
Alamiah
Simpanan
Diversitas sangat penting bagi pengelolaan
Olah tanah – minimum
Seresah sisa
panen
Olah tanah – dibajak
Aktivitas organisme
meningkat
Liang
cacing
tanah
Infiltrasi
Tanah –
Homogen
Lapisan
olah
Infiltrasi
Porositas dan Permeabilitas
• Ketersediaan air dalam tanah sangat kritis untuk
pertanian. Tanpa air, tidak ada yang dapat ditanam.
• Ada banyak cara untuk mengukur bagaimana tanah
berinteraksi dengan air.
– Porositas mengukur berapa banyak rongga di antara
partikel tanah yang dapat diisi oleh air dan udara.
– Permeability measures how easily water flows downward
through a soil to reach plant roots.
– Water holding capacity measures how much water is
retained in soil after it drains.
PERANAN ORGANISME TANAH (Dalam tanah)
MIKRO FLORA
BAKTERI
Paling banyak dijumpai dalam tanah, sifat Heterotrof atau autotrof, panjang 1 – 3 u m dengan diameter 0,5 – 1 u m.
*). Heterotrop (contoh : Arthrobakter)
Menggunakan BO sebagai sumber energi (populasi meningkat dengan penambahan BO), ada yang aerob dan
anaerob, suhu optimum 20 o C, pH 7 (4 – 10), memerlukan hara anorganik.
*). Autotropik (contoh : Nitrosomonas, Nitrobakter)
Menggunakan CO2 sebagai sumber energi dan mengoksidasi senyawa anorganik.
Beberapa kelompok bakteri lain :
^ Streptomyces : penghasil antibiotik (streptomycin), anti cendawan,
anti virus
^ Pseudomonas : beberapa spesies , sebagai penyebab penyakit
^ Bacillus : Fiksasi N
PERANAN :
1.
2.
3.
4.
5.
6.
Dekomposisi bahan organic (BO)
Fiksasi N non-simbiotik (Azotobacter, Clostridium, Bacillus)
Fiksasi N simbiotik (Rhizobium)
Nitrifikasi (Nitrosomonas, Nitrobakter)
Oksidasi Sulfur (Thiobacillus)
Patogen tanaman (Pseudomonas- penyakit Akar lunak)
Actinomycetes
Kebanyakan aerob, pH 5 atau lebih, sebagian besar psichrophiles, kebutuhan N rendah.
PERANAN :
Perombakan bahan organik (ppk kandang, sisa tanaman)
Pembentukan humus, penghancur selulosa
Fungi
•
Banyak didekat permukaan, Heterotrop, aerob, toleran terhadap genangan, toleran terhadap kemasaman/pH
rendah.
PERANAN : Penghancur selulosa dan lignin
Algae
•
•
Ada dipermukaan, mengandung khlorofil, Autotrop, toleran terhadap kemasaman dan genangan.
PERANAN :
Penting dalam kolonisasi, membantu proses pembentukan tanah
Penambat N2 pada padi sawah (contoh : Nostoc, Anabaena)
Kelompok Ganggang Tanah
•
•
•
•
•
•
- G. hijau (Chlorophyta). Contoh : Chlorella
- G. hijau-biru (Cyanophyta dan Cyanobakteria)
- Diatoms (Bacillariophyta)
- G. hijau-kuning (Xanthophyta)
PERANAN : Urutan kepentingan peranannya dalam tanah :
G. hijau > Diatomae > G. hijau biru > G. hijau kuning
MAKRO FAUNA
Oligochaete
(Contoh : Cacing tanah, hidup pada pH sekitar 7)
PERANAN : - Dekomposisi BO (melumatkan dan mencampur sisa tanaman), aerasi tanah, penetrasi
tanah, agegasi tanah
Molusca
(contoh : Siput, jumlahnya sangat kecil)
PERANAN : Mempunyai enzim selulase (>>>), merusak daun
Nematoada
(contoh : Cacing tidak bersegmen, panjang +/- 1 mm, diameter < 50 u m), aerob oblogat,
hidup pada tanah kasar dan lembab) Pemakan : protoplasma tanaman, ganggang, dan mikrobia
heterotrof.
PERANAN : Kurang penting dalam pembentukan humus.
Arthropoda
(Kaki seribu/millipede dan kaki seratus/centipede)
Saprofit (pemakan tanaman dan fauna yang mati), jumlahnya dalam tanah
sedikit.
Peranan lain dari mikro organisme.
1. Denitrifikasi : Perubahan nitrat -- nitrogen oksida (N2O) -- N2
tergenang, proses anaerob.
2.
Pada tanah
Fiksasi N
a. Non simbiotik = pengikatan bebas, organisme tanah memperoleh N dari udara dan
menggunakan BO sebagai sumber energi.
Azofikasi ; pengikatan N dari udara oleh Azotobacter.
b.
Simbiotik
= simbiosis antara mikroorganisme dan legume
Fiksasi N melalui bintil akar legum oleh bakteri Rhizobium
3. Pelarut senyawa Fosfat yang tidak larut oleh Bakteri Pelarut Fosfat.
4.
Penghasil metabolit
Zat pengatur tumbuh (ZPT) antar lain : Gibberilin, Auxin.
5.
Dekomposisi Bahan Organik
Jenis-jenis bakteri  fiksasi N
Mikrooganisme
Sifat
Penggunaan
Azotobacter
Aerobik, hidup bebas
dalam tanah, rhizosfer,
permukaan daun
Hormon pada akar &
pertumbuhan tanaman
Azospirillum
Mikroaerobik, bebas/
asosiasi dengan akar
rumput
Hormon pada akar &
pertumbuhan tanaman,
meningkatkan hasil rumput
Rhizobium
Simbiosis legum
Inokulasi dapat
menguntungkan tanaman
legum
Actinomicetes
Simbiosis non legum
Produksi kayu
Blue-green algae Hidup di air / daratan,
mengandung klorofil
Meningkatkan padi sawah
Blue-green Algae  Anabaena azolla Simbiosis Azolla
Perlu air, cahaya, N2, CO2, hara mineral
Pupuk
hijau
EKOSISTEM
TANAH
Ecosystems: Places where organisms interact with each other and
their abiotic environment
Organisme tanah berinteraksi dengan berbagai cara.
Misalnya, protozoa memangsa bakteri dan beberapa fungi
memangsa protozoa atau nematoda.
Fungi lainnya dimangsa oleh protozoa atau di-parasit-i oleh
nematoda.
Interactions among soil organisms may be very complex. They are
crucial to the functioning of soils.
An understanding of the nature of the organisms that live in soil is
essential for understanding soil ecology.
Diunduh dari:
http://www.safs.msu.edu/soilecology/soilbiology.htm…………. 20/3/2013
Organisme Tanah
Dalam satu meter persegi tanah ………….
Organisme menurun
ukurannya dan meningkat
jumlahnya
Diunduh dari:
http://organicsoilsolutions.com/services/compost-tea/…………. 20/3/2013
Struktur Ekosistem Tanah
Komponen Biotik dalam Tanah
Jumlah atau panjang
(dalam satu gengganm tanah)
Biomasa
(pounds / acre)
60 – 150 inches
(annual crops)
1,500 – 3,000 inches
(perennial grasses)
3,000
(annual crops)
15,000
(perennial grasses)
300 million – 50 billion
400 – 4,00
Akar Tumbuhan
•Plant residues (both roots and shoots)
are the ultimate source of almost all
carbon (energy) for soil organisms
•There may be 1,000 times more soil
microorganisms near plant roots than
in soil further away from roots
Bacteria
•Along with fungi, are the most
important group in organic matter
decomposition
•Extracellular compounds help bind
soil particles into aggregates
•Specialized groups are involved in
each portion of the nitrogen cycle
Diunduh dari:
http://www.safs.msu.edu/soilecology/soilbiology.htm…………. 20/3/2013
Struktur Ekosistem Tanah
Jumlah atau panjang
(dalam satu genggam tanah)
Biomasa
(pounds / acre)
•The most important group involved
in decomposing resistant compounds
such as lignin
•Hyphae grow extensively through
soils, helping bind soil particles in
500,000 – 100 million
aggregates
•Some specialized fungi grow
symbiotically with plant roots,
increasing nutrient and water
uptake and decreasing disease
incidence
500 – 5,000
Komponen Biotik dalam Tanah
Fungi
Actinomycetes
•Type of bacteria with growth form
similar to fungi; functions similar to 100 million – 2 billion
both
•Produce compounds that give soil
its distinctive aroma
Diunduh dari:
400 – 4,000
http://www.safs.msu.edu/soilecology/soilbiology.htm…………. 20/3/2013
Struktur Ekosistem Tanah
Jumlah atau panjang
(dalam satu genggam
tanah)
Biomasa
(pounds / acre)
Nematoda
Binatang yg jumlahnya paling
banyak dalam tanah
Membantu mempercepat
dekomposisi ketika mereka
memangsa bacteria, fungi dan
residu tanaman
1,000 – 10,000
5 – 50
Protozoa
Membantu mempercepat
dekomposisi ketika
memangsa bacteria, fungi dan
residu tumbuhan
100,000 – 50
million
5 – 100
Komponen Biotik dalam Tanah
Diunduh dari:
http://www.safs.msu.edu/soilecology/soilbiology.htm…………. 20/3/2013
Struktur Ekosistem Tanah
Komponen Biotik Tanah
Jumlah atau panjang
(dalam satu genggam
tanah)
Biomasa
(pounds / acre)
100 – 1,000
1 – 10
0–2
10 – 40
Arthropods
•Help accelerate decomposition when they
(mites, collembolan and other insects) graze
on bacteria, fungi and plant residues
•Collembola, shown in this photograph, are
an important arthropod in plant residue
decomposition
Cacing Tanah
Aktivitas membuat liang-liangnya
mencampur tanah dan menciptakan
pori makro yg meningkatkan infiltrasi
air dan aliran air dalam tanah serta
aerasi tanah
Material tanah yang melewati saluran
pencernaan cacing menghalami
peningkatan agregasi dan siklus hara
Diunduh dari:
http://www.safs.msu.edu/soilecology/soilbiology.htm…………. 20/3/2013
FUNGSI BIOTA TANAH
Diunduh dari:
http://www.safs.msu.edu/soilecology/soilbiology.htm…………. 20/3/2013
BAKTERI : Dekomposer / Konsumer
1.
2.
3.
4.
5.
6.
7.
8.
C/N ratio 5:1
Makan/ Metabolisme.
Transpor dan transformasi hara
Imobilisasi C dan N
Mineralisasi C dan N
Replikasi
Hibernasi
Mati (dimangsa)
Fungsi bakteri tanah
sebagai konsumer dan
dekomposer, menghasilkan
pola-pola khusus seperti
imobilisasi C dan N.
Diunduh dari: http://www.safs.msu.edu/soilecology/soilbiology.htm …………. 20/3/2013
Diversitas Nematoda
Diunduh dari:
http://www.safs.msu.edu/soilecology/soilbiology.htm…………. 20/3/2013
Nematoda: Konsumer
Nematoda dapat
menghasilkan
berbagai tipe jasa
ekosistem,
menghasilkan polapola khusus seperti
mobilisasi C dan N.
Diunduh dari:
http://www.safs.msu.edu/soilecology/soilbiology.htm…………. 20/3/2013
Populasi tertinggi
flagellata, amoeba,
dan ciliata ada
dalam lapisan
seresah (Ohorizon);
menunjukkan pola
yang khas.
Diunduh dari:
http://www.safs.msu.edu/soilecology/soilbiology.htm…………. 20/3/2013
Siklus Unsur Hara
In addition to obtaining inorganic nutrients and water from soil, the root
system serves as a host for various herbivores, including fungi, bacteria,
nematodes, arthropods and insects. Decomposers, including fungi, bacteria,
actinomycetes and earthworms, mineralize labile and resistant substrates (soil
organic matter).
Ini disebut sebagai interaksi order pertama.
Dalam interaksi order ke dua, organisme memangsa organisme yang terlibat
dalam interaksi order pertama.
Berbagai organisme tanah seperti nematoda, insekta, mite, fungi, bacteria,
dan protozoa berperilaku makan sebagai karnivora, bacterivora atau
fungivora memangsa organisme lain yang terlibat dalam tingkat aktivitas
(trofi) sebelumnya.
Diunduh dari:
http://www.safs.msu.edu/soilecology/soilbiology.htm …………. 20/3/2013
Organisme tanah dan Siklus Hara
Diunduh dari:
http://www.safs.msu.edu/soilecology/soilbiology.htm …………. 20/3/2013
Siklus rantai makanan Tanah (Food web)
Jaring-jaring makanan dalam tanah merupakan komunitas organisme yang
“interdependent” untuk sumber karbon dan energinya.
Diunduh dari: http://home.comcast.net/~pholowko/Soil%20Biology/SoilBiologyMainMenu.html …………. 20/3/2013
Jaring-jaring Makanan dalam Tanah
Pemakan
tumbuhan
(Grazer)
Foto-sintesis
Dekomposisi
Mineralisasi
Pemangsaan
Pelepasan hara
Predasi &
Grazing
Predasi
Diunduh dari: http://futurebeef.com.au/topics/grazing-land-management/soil-biology-%E2%80%93-what-is-it-all-about/ ………….
20/3/2013
Jaring-jaring Makanan dalam Tanah
Soil biology starts with carbon. Humus present in the soil provides food for the
most basic single-celled animals, which then provide a food source for the next
animals up the food chain and so on. The interactions between life, predation,
death and decay of these animals in the soil make up the complex system known as
a soil food web.
Jaring-jaring makanan dalam tanah mendeskripsikan huungan-hubungan di
antara semkua tingkat kehidupan dalam tanah. Fotosintesis dan pertumbuhan
tanaman menyediakan landasan bagi rantai makanan ini, dimana konsumer
akhir adalah grazers dan predators.
In turn the waste products of the higher level groups as they live, die and
decompose provide food for the plants. In some cases the loss of one animal or
plant species from the soil food web can lead to a breakdown in the whole cycle.
Diunduh dari: http://futurebeef.com.au/topics/grazing-land-management/soil-biology-%E2%80%93-what-is-it-all-about/ ………….
20/3/2013
MIKROBA TANAH
Mikroba tanah ini bekerja untuk:
1. Fiksasi nitrogen
2. Meningkatkan C tanah
3. Melepaskan mineral tanah yg terkunci
4. Mendetoksifikasi racun
5. Menyediakan makanan bagi tanaman dan
biota tanah
6. Membangun struktur tanah.
In general, the more biological life in our soil, the
greater the potential for improving or
maintaining current production levels.
Untuk meningkatkan dan memperbaiki biologi
tanah dalam pastures kita perlu:
1. maintain groundcover at 50 per cent organic
matter
2. reduce rainfall runoff and erosion
3. spell paddocks to allow for pasture recovery
4. maintain stocking rates appropriate for
current seasonal conditions
5. increase/maintain pasture species diversity.
Biologi tanah menderita kalau tidak cukup penutup muka lahannya, karena:
1. Lengas tanah berkurang dan suhu tanah meningkat
2. Siklus pembasahan/pengeringan lebih cepat
3. organic matter in the soil is reduced, and is often only provided by one or
two plant species rather than by a range of species, and
4. soil may be disturbed by erosion, vehicle traffic and tillage.
Diunduh dari: http://futurebeef.com.au/topics/grazing-land-management/soil-biology-%E2%80%93-what-is-it-all-about/ ………….
20/3/2013
BAKTERI TANAH
Bacteria adalah organisme kecil, bersel satu – umumnya ukuran lebarnya 4/100,000 inch
(1 µm) dan agak memanjang. Bakteri ini ukurannjya sangat kecil, jumlahnya snagat
banyak. Satu sendok teh tanah-produktif biasanya menmgandung bakteri sebanyak 100
million hingga 1 billion.
Bacteria dapat dikelompokkan menjadi empak kelompok fungsional.
1. Most are DECOMPOSERS That consume simple carbon compounds, such as root exudates and
fresh plant litter. By this process, bacteria convert energy in soil organic matter into forms useful to
the rest of the organisms in the soil food web. A number of decomposers can break down pesticides
and pollutants in soil. Decomposers are especially important in immobilizing, or retaining,
nutrients in their cells, thus preventing the loss of nutrients, such as nitrogen, from the rooting
zone.
2. A second group of bacteria are the MUTUALISTS that form partnerships with plants. The most
well-known of these are the nitrogen-fixing bacteria.
3. The third group of bacteria is the PATHOGENS. Bacterial pathogens include Xymomonas and
Erwinia species, and species of Agrobacterium that cause gall formation in plants.
4. Kelompok ke empat disebut lithotrophs atau chemoautotrophs, mendapatkan energinya
dari senyawa nitrogen, sulfur, iron atau hydrogen sebagai pengganti senyawa karbon. Beberapa
dari spesies ini penting dalam siklus nitrogen dan degradasi polutan.
Diunduh dari: http://soils.usda.gov/sqi/concepts/soil_biology/bacteria.html …………. 20/3/2013
BAKTERI TANAH
Empak kelompok Bacteria menghasilkan jasa-jasa penting yg berhubungan
dnegan dinamika air, siklus hara, dan kontrol penyakit.
Beberapa bakteri mempengaruhi pergerakan air tanah dnegan jalan
menghasilkan substansi yang menjedi eperekat partikel tanah membentuk
agregat-agregat yg berukuran kecil (diameter nya 1/10,000-1/100 inch atau 2
– 200 µm).
Agregat yg stabil memperbaiki infiltrasi air dan kemampuan tanah
menyimpan air.
In a diverse bacterial community, many organisms will compete with diseasecausing organisms in roots and on aboveground surfaces of plants.
Diunduh dari: http://soils.usda.gov/sqi/concepts/soil_biology/bacteria.html …………. 20/3/2013
BAKTERI TANAH
BEBERAPA BAKTERI PENTING
Bakteri fiksasi Nitrogen membentruk asosiasi simbiotik dengtan alar tanaman legume, jenis pohon dan
bukan pohon. Bintil akar dibentuk di tempat dimana bakteri menginfeksi bulu akar yg sedang
tumbuh. Tumbuhan mensuplai senyawa organik karbon sederhana kepada bakteri, dan bakteri
mengubah nitrogen (N2) dari udara menjadi bentuk senyawa yg dapat digunakan oleh tumbuhan.
Kalau daun atau akar tumbuhan host terdekomposisi , N-tanah meningkat.
Bakteri nitrifikasi mengubah ammonium (NH4+) menjadi nitrite (NO2-) kemudian menjadi nitrate
(NO3-) – bentuk nitrogen nyang disenangi oleh banyak jenis tanaman. Nitrat mudah tercuci ke luar
tanah, sehingga beberapa petani menggunakan penghambat nitrifikasi untuk mengurangi aktivitas
bakteri nitrifikasi. Bakteri Nitrifikasi terhambat aktivitasnya dalam tanah hutan, sehingga nitrogen
tanah berbentuk ammonium.
Denitrifying bacteria convert nitrate to nitrogen (N2) or nitrous oxide (N2O) gas. Denitrifiers are
anaerobic, meaning they are active where oxygen is absent, such as in saturated soils or inside soil
aggregates.
Actinomycetes are a large group of bacteria that grow as hyphae like fungi (see photo below). They are
responsible for the characteristically “earthy” smell of freshly turned, healthy soil. Actinomycetes
decompose a wide array of substrates, but are especially important in degrading recalcitrant (hard-todecompose) compounds, such as chitin and cellulose, and are active at high pH levels. Fungi are more
important in degrading these compounds at low pH. A number of antibiotics are produced by
actinomycetes such as Streptomyces.
Diunduh dari: http://soils.usda.gov/sqi/concepts/soil_biology/bacteria.html …………. 20/3/2013
BAKTERI TANAH
Various species of bacteria thrive on different food sources and in different
microenvironments. In general, bacteria are more competitive when labile (easy-tometabolize) substrates are present. This includes fresh, young plant residue and the
compounds found near living roots. Bacteria are especially concentrated in the
rhizosphere, the narrow region next to and in the root. There is evidence that plants
produce certain types of root exudates to encourage the growth of protective bacteria.
Bacteria mampu mengubah kondisi lingkungan tanah sehingga sangat sesuai bagi
komunitas tumbuhan tetrtentu dibandingkan dnegan lainnya. Sebelum tumbuhan
berkembang pada bahan sedimen segar, komunitas bakteri harus berkembang lebih
dfahulu, mulai dengan bakteri yang mampu berfotosintesis.
These fix atmospheric nitrogen and carbon, produce organic matter, and immobilize
enough nitrogen and other nutrients to initiate nitrogen cycling processes in the young soil.
Then, early successional plant species can grow. As the plant community is established,
different types of organic matter enter the soil and change the type of food available to
bacteria. In turn, the altered bacterial community changes soil structure and the
environment for plants.
Diunduh dari: http://soils.usda.gov/sqi/concepts/soil_biology/bacteria.html …………. 20/3/2013
FUNGI TANAH
Fungi adalah sel mikroskopis yg biasanya menumbuhkan benang-benang panjang
yg disebut HIFA, yang mampu menembus rongga di antara partikel tanah, akar
dan batuan. Hifa biasanya mempunyai diameter hanya beberapa micrometer.
Hifa tunggal dapat memanjang mulai dari beberapa sel hingga ber-meter
panjangnya. Bebertapa jenis fungi, seperti ragi , adalah ber-sel tunggal.
Hyphae sometimes group into masses called mycelium or thick, cord-like “rhizomorphs”
that look like roots. Fungal fruiting structures (mushrooms) are made of hyphal strands,
spores, and some special structures like gills on which spores form. A single individual
fungus can include many fruiting bodies scattered across an area as large as a baseball
diamond.
Fungi perform important services related to water dynamics, nutrient cycling, and disease
suppression. Along with bacteria, fungi are important as decomposers in the soil food web.
They convert hard-to-digest organic material into forms that other organisms can use.
Fungal hyphae physically bind soil particles together, creating stable aggregates that help
increase water infiltration and soil water holding capacity.
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FUNGI TANAH
Fungi tanah dapat dikelompokkan menjadi tiga kelompok
fungsional berdasarkan caranya mendapatkan energi.
Decomposer – fungi saprofitik –
mengubah bahan organiki mati menjadi biomasa
fungi, carbon dioxide (CO2), dan molekul-molekul kecil, seperti asam-asam organik.
Fungi ini umumnya menggunakan senyawa organik kompleks, seperti cellulose dan
lignin, dalam kayu, dan sangat penting dalam dekomposisi struktur cincin karbon dalam
beberapa jenis polutan.
A few fungi are called “sugar fungi” because they use the same simple substrates as do
many bacteria. Like bacteria, fungi are important for immobilizing, or retaining,
nutrients in the soil. In addition, many of the secondary metabolites of fungi are organic
acids, so they help increase the accumulation of humic-acid rich organic matter that is
resistant to degradation and may stay in the soil for hundreds of years.
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FUNGI TANAH
Mutualists – fungi mikorhiza – meng-koloni akar tanaman. Dalam menukar karbon
dari tanaman, fungi mycorrhiza membantu melarutkan phosphorus dan membawa hara
tanah (phosphorus, nitrogen, micronutrients, dan air) masuk ke dalam tanaman.
One major group of mycorrhizae, the ectomycorrhizae (see third photo below), grow on
the surface layers of the roots and are commonly associated with trees. The second major
group of mycorrhizae are the endomycorrhizae that grow within the root cells and are
commonly associated with grasses, row crops, vegetables, and shrubs. Arbuscular
mycorrhizal (AM) fungi are a type of endomycorrhizal fungi (see fourth photo below).
Ericoid mycorrhizal fungi can by either ecto- or endomycorrhizal.
Pathogens or parasites, menyebabkan penurunan produksi dan kematian kalau
mereka meng-koloni akar dabn organisme lainnya. Fungi patogenik akar, seperti
Verticillium, Pythium, dan Rhizoctonia, menyebabkan kerugian eknomis yg sangat besar
dalam pertanian setiap tahun. Many fungi help control diseases. For example, nematodetrapping fungi that parasitize disease-causing nematodes, and fungi that feed on insects
may be useful as biocontrol agents.
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FUNGI TANAH
Banyak tumbuhan
menggantungkan pada fungi
untuk membantu mengekstraks
hara dari tanah. Tree roots
(brown) are connected to the
symbiotic mycorrhizal
structure (bright white) and
fungal hyphae (thin white
strands) radiating into the
soil.
Credit: Randy Molina, Oregon State
University, Corvallis. Please contact
the Soil and Water Conservation
Society at [email protected] for
assistance with copyrighted
(credited) images.
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FUNGI TANAH
Ectomycorrhiza sangat penting
untuk penyerapan hara oleh
akar pohon dan akar tanaman
anggur. Fungi ini sebenarnya
tidak menginvasi akar tetapi
hanya membentuk selimut yang
menembus di antara sel-sel
tumbuhan.
The sheath in this photo is
white, but they may be black,
orange, pink, or yellow.
Credit: USDA, Forest Service, PNW
Research Station, Corvallis, Oregon.
Please contact the Soil and Water
Conservation Society at [email protected]
for assistance with copyrighted (credited)
images.
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FUNGI TANAH
Fungi memulai proses
dekomposisi tulang-tulang
daun dalam seresah
rerumputan.
Credit: No. 48 from Soil Microbiology
and Biochemistry Slide Set. 1976. J.P.
Martin, et al., eds. SSSA, Madison WI.
Please contact the Soil and Water
Conservation Society at
[email protected] for assistance with
copyrighted (credited) images.
Diunduh dari:
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FUNGI TANAH
Fungi Saprofitik biasanya aktif di dalam residu tumbuhan berkayu.. Hifa fungi
mempunyai keuntungan dibandingkan dengan bakteri, dalam beberapa kondisi
lingkungan tertentu.
Pada kondisi kering, fungi dapat menjembatani di antara kantong-kantong
lengas tanah dan terus dapat tumbuh dan hidup meskipun kandungan air tanah
terlalu rendah bagi kehidupan bakteri.
Fungi mampu menggunakan nitrogen dari tanah, memungkinkannya untuk
melakukan dekomposisi residu di permukaan tanah yang seringkali miskjn
nitrogen.
Fungi are aerobic organisms. Soil which becomes anaerobic for significant
periods generally loses its fungal component. Anaerobic conditions often occur
in waterlogged soil and in compacted soils.
Fungi are especially extensive in forested lands. Forests have been observed to
increase in productivity as fungal biomass increases.
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FUNGI TANAH
MYCORRHIZA DALAM PERTANIAN
Mycorrhiza adalah asosiasi simbiotik antara fungi dan akar tumbuhan dan
berbeda dnegan fungi atau akar itu sendiri. Banyak jenis pohon dan tanaman
pertanian mendapatkan manfaat dari mikorhiza.
Tingkat ketergantungannya pada mikorhiza sangat beragam di antara varietas
tanaman, termasug gandum dan jagung.
Land management practices affect the formation of mycorrhizae. The number
of mycorrhizal fungi in soil will decline in fallowed fields or in those planted to
crops that do not form mycorrhizae. Frequent tillage may reduce mycorrhizal
associations, and broad spectrum fungicides are toxic to mycorrhizal fungi. Very
high levels of nitrogen or phosphorus fertilizer may reduce inoculation of roots.
Beberapa inokulum fungi mikorhiza tersedia secara komersial dan dapat
diaplikasikan ke tanah pada saat tanam.
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FUNGI TANAH
Mycorrhizal fungi link root cells to soil
particles. In the photo at left, sand
grains are bound to a root by hyphae
from endophytes (fungi similar to
mycorrhizae), and by polysaccharides
secreted by the plant and the fungi.
Credit: Jerry Barrow, USDA-ARS
Jornada Experimental Range, Las
Cruces, NM. Please contact the Soil
and Water Conservation Society at
[email protected] for assistance with
copyrighted (credited) images.
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PROTOZOA TANAH
Protozoa adalah binatang bersel tunggal, yang memangsa bacteria, tetapi juga
memangsa protozoa lainnya, bahan organik larut, dan kadangkala memangsa
fungi. Ukurannya beberapa kali lebihy besar dibandingkan dnegan bakteri –
diameternya berkisar 1/5000 - 1/50 inchi (5 - 500 µm). As they eat bacteria,
protozoa release excess nitrogen that can then be used by plants and other
members of the food web.
Protozoa are classified into three groups based on their shape: Ciliates are the
largest and move by means of hair-like cilia. They eat the other two types of
protozoa, as well as bacteria. Amoebae also can be quite large and move by
means of a temporary foot or “pseudopod.”
Amoeba dapat dibagi lagi menjadi testate amoebae (yg membuat selimut seperti
kulit) dan naked amoebae (tanpa selimut).
Flagellata merupakan protozoa paling kecil dan menggunakan beberapa flagella
untuk bergerak.
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PROTOZOA TANAH
Protozoa berperan epenting
dalam siklus hara dengan jalan
memangsa bakteri.
Notice the size of the speck-like
bacteria next to the oval
protozoa and large, angular
sand particle.
Credit: Elaine R. Ingham. Please
contact the Soil and Water
Conservation Society at
[email protected] for assistance with
copyrighted (credited) images.
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PROTOZOA TANAH
Bacteria dimakan oleh
amoeba.
Credit: No. 35 from Soil
Microbiology and Biochemistry
Slide Set. 1976. J.P. Martin, et al.,
eds. SSSA, Madison, WI. Please
contact the Soil and Water
Conservation Society at
[email protected] for assistance with
copyrighted (credited) images.
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PROTOZOA TANAH
Flagellata mempunyai satu
atau dua flagella yang
digunakan untuk bergerak
menembus tanah.
A flagellum can be seen
extending from the protozoan
on the left. The tiny specks
are bacteria.
Credit: Elaine R. Ingham. Please
contact the Soil and Water
Conservation Society at
[email protected] for assistance
with copyrighted (credited)
images.
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PROTOZOA TANAH
Ciliata adalah protozoa yg
ukurannya besar dan
jumlahnya sedikit.
Mereka mengkonsumsi
puluhan ribu bakteri setiap
hari, dan melepaskan
nitrogen tersedia bagi
tumbuhan. Ciliates use the
fine cilia along their bodies
like oars to move rapidly
through soil.
Credit: Elaine R. Ingham.
Please contact the Soil and
Water Conservation Society at
[email protected] for assistance
with copyrighted (credited)
images.
Diunduh dari: http://soils.usda.gov/sqi/concepts/soil_biology/bacteria.html …………. 20/3/2013
APA KERJA PROTOZOA TANAH ?
Protozoa berperan penting dalam mineralisasi unsur hara, membuat hara menjadi
tersedia bagi tumbuhan dan bagi organisme tanah lainnya. Protozoa (dan nematoda)
mempunyai konsnetrasi N lebih rendah dalam sel-selnya dibandingkan dnegan bakteri
mangsanya. (C/N ratio untuk protozoa adalah 10:1 atau lebih tinggi, dan 3:1 - 10:1
untuk bakteri.)
Bacteria eaten by protozoa contain too much nitrogen for the amount of carbon protozoa
need. They release the excess nitrogen in the form of ammonium (NH4+). This usually
occurs near the root system of a plant. Bacteria and other organisms rapidly take up
most of the ammonium, but some is used by the plant.
Another role that protozoa play is in regulating bacteria populations. When they graze on
bacteria, protozoa stimulate growth of the bacterial population (and, in turn,
decomposition rates and soil aggregation.) Exactly why this happens is under some
debate, but grazing can be thought of like pruning a tree – a small amount enhances
growth, too much reduces growth or will modify the mix of species in the bacterial
community.
Protozoa menjadi sumber makanan yg penting bagi organisme tanah lainnya dan
membantu menekan penyakit dengan jalan berkompetisi atau memangsa patogen.
Diunduh dari: http://soils.usda.gov/sqi/concepts/soil_biology/bacteria.html …………. 20/3/2013
MINERALISASI DAN IMOBILISASI
Diunduh dari: http://soils.usda.gov/sqi/concepts/soil_biology/bacteria.html …………. 20/3/2013
DIMANA PROTOZOA TANAH ?
Protozoa need bacteria to eat and water in which to move, so moisture plays a
big role in determining which types of protozoa will be present and active. Like
bacteria, protozoa are particularly active in the rhizosphere next to roots.
Typical numbers of protozoa in soil vary widely – from a thousand per teaspoon
in low fertility soils to a million per teaspoon in some highly fertile soils. Fungaldominated soils (e.g. forests) tend to have more testate amoebae and ciliates than
other types. In bacterial-dominated soils, flagellates and naked amoebae
predominate.
Umumnya, tanah-tanah yg kaya liat mengandung lebih banyak protozoa yg
ukurannya elbih kecil (flagellata dan amoeba), sedangkan tanah-tanah tekstur
kasar mengandung flagellata besar, amoeba dan ciliata.
Diunduh dari: http://soils.usda.gov/sqi/concepts/soil_biology/bacteria.html …………. 20/3/2013
NEMATODA TANAH
Nematodes are non-segmented worms typically 1/500 of an inch (50 µm) in diameter and
1/20 of an inch (1 mm) in length. Those few species responsible for plant diseases have
received a lot of attention, but far less is known about the majority of the nematode
community that plays beneficial roles in soil.
An incredible variety of nematodes function at several trophic levels of the soil food web.
Some feed on the plants and algae (first trophic level); others are grazers that feed on
bacteria and fungi (second trophic level); and some feed on other nematodes (higher
trophic levels).
Nematode hidup-bebas dikelompokkan menjadi empat kelompok berdasarkan pola
makanannya:
1. Bacterial-feeders memangsa bakteri.
2. Fungal-feeders makan dnegan jalan menembus dinding sel fungi dan menghisap isi
selnya.
3. Predatory nematodes memangsa semua tipe nematoda dan protozoa. They eat smaller
organisms whole, or attach themselves to the cuticle of larger nematodes, scraping
away until the prey’s internal body parts can be extracted.
4. Omnivores memangsa berbagai organisme atau mempunyai pola diet yg berbeda
pada setiap fase hidupnya.
5. Root-feeders bersifat parasit tumbuhan, dan tidak hidup bebas dalam tanah.
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NEMATODA
TANAH
Kebanyakan nematode tanah
bukan parasit bagi tumbuhan.
Nematoda yg menguntungkan
dapat membantu mengendalikan
penyakit dan siklus hara.
Credit: Elaine R. Ingham. Please
contact the Soil and Water
Conservation Society at
[email protected] for assistance with
copyrighted (credited) images.
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NEMATODA
TANAH
Nematoda predator memangsa
nematode yang lebih kecil.
Credit: Kathy Merrifield, Oregon State
University, Corvallis. Please contact the
Soil and Water Conservation Society at
[email protected] for assistance with
copyrighted (credited) images.
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APA KERJA NEMATODA TANAH ?
Siklus Hara.
Nematodes are important in mineralizing, or releasing, nutrients in plant-available forms.
When nematodes eat bacteria or fungi, ammonium (NH4+) is released because bacteria and
fungi contain much more nitrogen than the nematodes require.
Grazing.
At low nematode densities, feeding by nematodes stimulates the growth rate of prey
populations. That is, bacterial-feeders stimulate bacterial growth, plant-feeders stimulate
plant growth, and so on. At higher densities, nematodes will reduce the population of their
prey. This may decrease plant productivity, may negatively impact mycorrhizal fungi, and
can reduce decomposition and immobilization rates by bacteria and fungi.
Predatory nematodes may regulate populations of bacterial-and fungal-feeding nematodes,
thus preventing over-grazing by those groups. Nematode grazing may control the balance
between bacteria and fungi, and the species composition of the microbial community.
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APA KERJA NEMATODA TANAH ?
Penyebaran Mikroba.
Nematodes help distribute bacteria and fungi through the soil and along roots by carrying
live and dormant microbes on their surfaces and in their digestive systems.
SUMBER MAKANAN.
Nematoda menjadi makanan bagi predator tingkat yg lebih tinggi, termasuk nematode
predator, microarthropoda tanah, dan insekta tanah. Mereka juga dapat di-parasit-i oleh
bacteria dan fungi.
Mengendlaikan penyakit.
Some nematodes cause disease. Others consume disease-causing organisms, such as rootfeeding nematodes, or prevent their access to roots. These may be potential biocontrol
agents.
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NEMATODA
TANAH
Nematode pemangsa fungi
mempunyai stylets kecil dan
tajam di bagian mulutnya,
yang digunakan untuk
menembus dinding sel hifa
fungi dan menyerap cairan
selnya.
This interaction releases
plant-available nitrogen from
fungal biomass.
Credit: Elaine R. Ingham. Please
contact the Soil and Water
Conservation Society at
[email protected] for assistance
with copyrighted (credited)
images.
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NEMATODA
TANAH
Nematode pemangsa bakteri,
Elaphonema, mempunyai
struktur seperti bibir yg
membedakannya dengan
nematode lainnya.
Bacterial-feeders release plantavailable nitrogen when they
consume bacteria.
Credit: Elaine R. Ingham. Please
contact the Soil and Water
Conservation Society at
[email protected] for assistance with
copyrighted (credited) images.
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DIMANA NEMATODA TANAH ?
Nematodes are concentrated near their prey groups. Bacterial-feeders abound
near roots where bacteria congregate; fungal-feeders are near fungal biomass;
root-feeders are concentrated around roots of stressed or susceptible plants.
Predatory nematodes are more likely to be abundant in soils with high numbers
of nematodes.
Because of their size, nematodes tend to be more common in coarser-textured
soils. Nematodes move in water films in large (>1/500 inch or 50 µm) pore spaces.
Tanah pertanian biasanya mengandung kurang darti 100 nematoda dalam setiap
sendok teh (dry gram) tanah. Lahan berumput mengandung 50 - 500 nematoda,
dan tanah-tanah butan mengandung beberapa ratus nematode dalam setiap
sendok-teh tanah.
The proportion of bacterial-feeding and fungal-feeding nematodes is related to
the amount of bacteria and fungi in the soil. Commonly, less disturbed soils
contain more predatory nematodes, suggesting that predatory nematodes are
highly sensitive to a wide range of disturbances.
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ARTHROPODA
TANAH
Many bugs, known as arthropods, make their home in the soil. They get their
name from their jointed (arthros) legs (podos). Arthropods are invertebrates, that
is, they have no backbone, and rely instead on an external covering called an
exoskeleton.
Arthropods range in size from microscopic to several inches in length. They
include insects, such as springtails, beetles, and ants; crustaceans such as sowbugs;
arachnids such as spiders and mites; myriapods, such as centipedes and
millipedes; and scorpions.
Nearly every soil is home to many different arthropod species. Certain row-crop
soils contain several dozen species of arthropods in a square mile. Several
thousand different species may live in a square mile of forest soil.
Arthropods can be grouped as shredders, predators, herbivores, and fungalfeeders, based on their functions in soil. Most soil-dwelling arthropods eat fungi,
worms, or other arthropods. Root-feeders and dead-plant shredders are less
abundant. As they feed, arthropods aerate and mix the soil, regulate the
population size of other soil organisms, and shred organic material.
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ARTHROPODA
TANAH
SHREDDERS
Many large arthropods frequently seen on the soil surface are shredders. Shredders chew up dead
plant matter as they eat bacteria and fungi on the surface of the plant matter. The most abundant
shredders are millipedes and sowbugs, as well as termites, certain mites, and roaches. In
agricultural soils, shredders can become pests by feeding on live roots if sufficient dead plant
material is not present.
Millipedes are also called Diplopods because
they possess two pairs of legs on each body
segment. They are generally harmless to
people, but most millipedes protect themselves
from predators by spraying an offensive odor
from their skunk glands. This desert-dwelling
giant millipede is about 8 inches long.
Orthoporus ornatus.
Credit: David B. Richman, New Mexico State
University, Las Cruces. Please contact the Soil and
Water Conservation Society at [email protected] for
assistance with copyrighted (credited) images.
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ARTHROPODA
TANAH
PREDATORS
Predators and micropredators can be either generalists, feeding on many different prey types, or specialists,
hunting only a single prey type. Predators include centipedes, spiders, ground-beetles, scorpions, skunkspiders, pseudoscorpions, ants, and some mites. Many predators eat crop pests, and some, such as beetles and
parasitic wasps, have been developed for use as commercial biocontrols.
This 1/8 of an inch long spider lives near
the soil surface where it attacks other soil
arthropods. The spider's eyes are on the
tip of the projection above its head.
Walckenaera acuminata.
Credit: Gerhard Eisenbeis and Wilfried
Wichard. 1987. Atlas on the Biology of Soil
Arthropods. Springer-Verlag, New York. P.
23. Please contact the Soil and Water
Conservation Society at [email protected] for
assistance with copyrighted (credited)
images.
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ARTHROPODA TANAH
The wolf-spider wanders
around as a solitary hunter.
The mother wolf-spider
carries her young to water
and feeds them by
regurgitation until they are
ready to hunt on their own.
Credit: Trygve Steen, Portland
State University, Portland,
Oregon. Please contact the Soil
and Water Conservation Society
at [email protected] for assistance
with copyrighted (credited)
images.
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ARTHROPODA
TANAH
Predatory mites prey on nematodes,
springtails, other mites, and the
larvae of insects. This mite is 1/25 of
an inch (1mm) long. Pergamasus sp.
Credit: Gerhard Eisenbeis and Wilfried
Wichard. 1987. Atlas on the Biology of Soil
Arthropods. Springer-Verlag, New York. P.
83. Please contact the Soil and Water
Conservation Society at [email protected] for
assistance with copyrighted (credited)
images.
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ARTHROPODA TANAH
HERBIVORA
Banyak insekta pemakan akar, seperti cicada, mole-cricket, dan anthomyiid flies (ngengat akar),
sebagian atau seluruh hidupnya di dalam tanah.
Some herbivores, including rootworms and symphylans, can be crop pests where they occur in
large numbers, feeding on roots or other plant parts.
Jenis symphylan, centipeda,
memakan akar tumbuhan dan
dapat menjadi hama utama kalau
populasinya tidak dikendalikan
oleh organisme lain.
Credit: Ken Gray Collection, Department
of Entomology, Oregon State University,
Corvallis. Please contact the Soil and
Water Conservation Society at
[email protected] for assistance with
copyrighted (credited) images.
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APA KERJA ARTHROPODA TANAH ?
Although the plant feeders can become pests, most arthropods perform beneficial functions in the soilplant system.
Menghancurkan bahan organik.
Arthropods increase the surface area accessible to microbial attack by shredding dead plant residue
and burrowing into coarse woody debris. Without shredders, a bacterium in leaf litter would be like a
person in a pantry without a can-opener – eating would be a very slow process. The shredders act like
can-openers and greatly increase the rate of decomposition. Arthropods ingest decaying plant material
to eat the bacteria and fungi on the surface of the organic material.
Menstumulir aktivitas mikroba.
As arthropods graze on bacteria and fungi, they stimulate the growth of mycorrhizae and other fungi,
and the decomposition of organic matter. If grazer populations get too dense the opposite effect can
occur – populations of bacteria and fungi will decline. Predatory arthropods are important to keep
grazer populations under control and to prevent them from over-grazing microbes.
Mencampur mikroba dengan makanannya.
Bacteria have limited mobility in soil and a competitor is likely to be closer to a nutrient treasure.
Arthropods help out by distributing nutrients through the soil, and by carrying bacteria on their
exoskeleton and through their digestive system. By more thoroughly mixing microbes with their food,
arthropods enhance organic matter decomposition.
Diunduh dari: http://soils.usda.gov/sqi/concepts/soil_biology/bacteria.html …………. 20/3/2013
APA KERJA ARTHROPODA TANAH ?
Mineralisasi Hara Tanaman.
As they graze, arthropods mineralize some of the nutrients in bacteria and fungi, and excrete nutrients
in plant-available forms.
Membantu agregasi tanah.
In most forested and grassland soils, every particle in the upper several inches of soil has been through the gut of
numerous soil fauna. Each time soil passes through another arthropod or earthworm, it is thoroughly mixed with
organic matter and mucus and deposited as fecal pellets. Fecal pellets are a highly concentrated nutrient resource, and
are a mixture of the organic and inorganic substances required for growth of bacteria and fungi. In many soils,
aggregates between 1/10,000 and 1/10 of an inch (0.0025mm and 2.5mm) are actually fecal pellets.
LIANG-LIANG NYA.
Relatively few arthropod species burrow through the soil. Yet, within any soil community, burrowing
arthropods and earthworms exert an enormous influence on the composition of the total fauna by
shaping habitat. Burrowing changes the physical properties of soil, including porosity, waterinfiltration rate, and bulk density.
Menstimulir Suksesi Spesies.
A dizzying array of natural bio-organic chemicals permeates the soil. Complete digestion of these chemicals requires a
series of many types of bacteria, fungi, and other organisms with different enzymes. At any time, only a small subset of
species is metabolically active – only those capable of using the resources currently available. Soil arthropods consume
the dominant organisms and permit other species to move in and take their place, thus facilitating the progressive
breakdown of soil organic matter.
and diverse food web.
Diunduh dari: http://soils.usda.gov/sqi/concepts/soil_biology/bacteria.html …………. 20/3/2013
APA KERJA ARTHROPODA TANAH ?
Pengendalian Hama.
Some arthropods can be damaging to crop yields, but many others that are present in all
soils eat or compete with various root- and foliage-feeders. Some (the specialists) feed on
only a single type of prey species.
Other arthropods (the generalists), such as many species of centipedes, spiders, groundbeetles, rove-beetles, and gamasid mites, feed on a broad range of prey.
Kalau ada populasi yg sehat predator generalis, mereka akan mampu mengendalikan
berbagai gangguan ledakan hama.
Populasi predator hanya dapat dipertahankan di antara outbreaks hama, kalau tersedia
sumber makanan berupa mangsa non-hama. Sehingga harus ada jaring-jaring makanan
yang sehat dan beragam.
Diunduh dari: http://soils.usda.gov/sqi/concepts/soil_biology/bacteria.html …………. 20/3/2013
DIMANA ARTHROPODA TANAH ?
Kelimpahan dan diversitas fauna tanah menurun signifikan dengan kedalaman tanah.
Sebagian besar organisme tanah jenis ini hidup dalam tanah lapisan atas setebal tiga inchi.
Kebanyakan dari mereka ini mobilitasnya sangat terbatas, dan mungkin mampu
melakukan “cryptobiosis,” suatu kondisi “suspended animation” yg membantunya untuk
bertahan pada kondisi suhu ekstrim, kebasahan, atau kekeringan yang dapat
mematikannya.
As a general rule, larger species are active on the soil surface, seeking temporary refuge
under vegetation, plant residue, wood, or rocks. Many of these arthropods commute daily to
forage within herbaceous vegetation above, or even high in the canopy of trees. (For
instance, one of these tree-climbers is the caterpillar-searcher used by foresters to control
gypsy moth). Some large species capable of true burrowing live within the deeper layers of
the soil.
Below about two inches in the soil, fauna are generally small – 1/250 to 1/10 of an inch.
(Twenty-five of the smallest of these would fit in a period on this page.)
These species are usually blind and lack prominent coloration. They are capable of
squeezing through minute pore spaces and along root channels. Sub-surface soil dwellers
are associated primarily with the rhizosphere (the soil volume immediately adjacent to
roots).
Diunduh dari: http://soils.usda.gov/sqi/concepts/soil_biology/bacteria.html …………. 20/3/2013
CACING TANAH
DARI semua anggota jaring-jaring makanan tanah, cacing tanah paling dikenal. Banyak
orang telah mengenal cacing-tanah yang tubuhnya lunak, berlendir, invertebrata.. Cacing
tanah bersifat hermaphrodit , menunjukkan karakteristik betina dan jantan.
They are major decomposers of dead and decomposing organic matter, and derive their
nutrition from the bacteria and fungi that grow upon these materials. They fragment
organic matter and make major contributions to recycling the nutrients it contains.
Earthworms occur in most temperate soils and many tropical soils. They are divided into 23
families, more than 700 genera, and more than 7,000 species. They range from an inch to
two yards in length and are found seasonally at all depths in the soil.
Dalam hal biomassa dan aktivitasnya, cacing-tanah mendominasi dunia invertebrata tanah,
termasuk arthropoda.
Diunduh dari: http://soils.usda.gov/sqi/concepts/soil_biology/bacteria.html …………. 20/3/2013
CACING TANAH
Cacing tanah
menghasilkan kotorannya
(castcing) berton-ton per
hektar per tahun, mampu
mengubah struktur tanah
secara dramatis.
Credit: Clive A. Edwards, The
Ohio State University, Columbus.
Soil and Water Conservation
Society at [email protected] for
assistance with copyrighted
(credited) images.
Diunduh dari: http://soils.usda.gov/sqi/concepts/soil_biology/bacteria.html …………. 20/3/2013
APA KERJANYA CACING TANAH
Earthworms dramatically alter soil structure, water movement, nutrient dynamics, and
plant growth. They are not essential to all healthy soil systems, but their presence is usually
an indicator of a healthy system.
Earthworms perform several beneficial functions:
1. Menstimulir aktivitas mikroba. Although earthworms derive their nutrition from
microorganisms, many more microorganisms are present in their feces or casts than in
the organic matter that they consume. As organic matter passes through their intestines,
it is fragmented and inoculated with microorganisms. Increased microbial activity
facilitates the cycling of nutrients from organic matter and their conversion into forms
readily taken up by plants.
2. Mencampur dan mengagregasi tanah. As they consume organic matter and mineral
particles, earthworms excrete wastes in the form of casts, a type of soil aggregate.
Charles Darwin calculated that earthworms can move large amounts of soil from the
lower strata to the surface and also carry organic matter down into deeper soil layers. A
large proportion of soil passes through the guts of earthworms, and they can turn over
the top six inches (15 cm) of soil in ten to twenty years.
Diunduh dari:
…………. 20/3/2013
APA KERJANYA CACING TANAH
1. Meningkatkan infiltrasi. Earthworms enhance porosity as they move through the soil.
Some species make permanent burrows deep into the soil. These burrows can persist
long after the inhabitant has died, and can be a major conduit for soil drainage,
particularly under heavy rainfall. At the same time, the burrows minimize surface water
erosion. The horizontal burrowing of other species in the top several inches of soil
increases overall porosity and drainage.
2. Memperbaiki kapasitas simpanan air tanah. By fragmenting organic matter, and
increasing soil porosity and aggregation, earthworms can significantly increase the
water-holding capacity of soils.
3. Menyediakan rongga/saluran bagi pertumbuhan akar. The channels made by deepburrowing earthworms are lined with readily available nutrients and make it easier for
roots to penetrate deep into the soil.
4. Mengubur dan menghancurkan residu tumbuhan. Plant and crop residue are gradually
buried by cast material deposited on the surface and as earthworms pull surface residue
into their burrows.
Diunduh dari:
…………. 20/3/2013
CACING TANAH
Campuran tanah dan
bahan organik di dalam
liang cacing –tanah.
Cacing-tanah
memasukkan banyak
bahan organik ke dalam
tanah.
Credit: Clive A. Edwards, The
Ohio State University,
Columbus.
The Soil and Water
Conservation Society at
[email protected] for assistance
with copyrighted (credited)
images.
Diunduh dari: http://soils.usda.gov/sqi/concepts/soil_biology/bacteria.html …………. 20/3/2013
CACING TANAH
Beberapa jenis cacing hidup dalam
liang vertikal yang permanen.
Jenis lainnya mempunyai liang
horisontal di dekat permukaan
tanah, mengisi liangnya dengan
kotoran (castcing) kalau
ditinggalkannya.
Credit: North Appalachian Experimental
Watershed, USDA-Agricultural Research Service,
Coshocton, Ohio. Please contact the Soil and Water
Conservation Society at [email protected] for
assistance with copyrighted (credited) images.
Diunduh dari: http://soils.usda.gov/sqi/concepts/soil_biology/bacteria.html …………. 20/3/2013
DIMANA CACING TANAH ?
Berbagai species cacing-tanah menghuni berbagai bagian tanah dan mempunyai strategi makan yang
spesifik. Mereka ini dapat dikelompokkan menjadi tiga kelompok ekmologis berdasarkan perilaku
makannya dan caranya membuat liang. Kesemua kelompok ini sangat terkenal dan dapat
memperbaiki struktur tanah.
1. Spesies Epigeik: Surface soil and litter species. These species live in or near surface plant litter.
They are typically small and are adapted to the highly variable moisture and temperature
conditions at the soil surface. The worms found in compost piles are epigeic and are unlikely to
survive in the low organic matter environment of soil.
2. Spesies Endogeik: Upper soil species. Some species move and live in the upper soil strata and feed
primarily on soil and associated organic matter (geophages). They do not have permanent burrows,
and their temporary channels become filled with cast material as they move through the soil,
progressively passing it through their intestines.
3. Spesies Anesik: Deep-burrowing species. These earthworms, which are typified by the “night
crawler,” Lumbricus terrestris, inhabit more or less permanent burrow systems that may extend
several meters into the soil. They feed mainly on surface litter that they pull into their burrows.
They may leave plugs, organic matter, or cast (excreted soil and mineral particles) blocking the
mouth of their burrows.
Diunduh dari: http://soils.usda.gov/sqi/concepts/soil_biology/bacteria.html …………. 20/3/2013
KELIMPAHAN & DISTRIBUSI CACING TANAH
The majority of temperate and many tropical soils support significant earthworm
populations. A square yard of cropland can contain from 50-300 earthworms, or even larger
populations in highly organic soils. A similar area of grassland or temperate woodlands will
have from 100-500 earthworms. Based on their total biomass, earthworms are the
predominant group of soil invertebrates in most soils.
The family of earthworms that is most important in enhancing agricultural soil is
Lumbricidae, which includes the genuses Lumbricus, Aporrectodea, and several others.
Cacing tanah lebih banyak dalam tanah lempung , lempung liat, dan tanah berdebu; lebih
sedikit dalam tanah berpasir dan tanah liat berat.
Populasi cacing-tanah meningkat dalam tanah irigasi.
Populasi cenderung meningkat dengan kandungan bahan organik tanah dan menurun
dengan adanya gangguan tanah, seperti pengolahan tanah dan bahan kimia berbahaya.
Diunduh dari: http://soils.usda.gov/sqi/concepts/soil_biology/bacteria.html …………. 20/3/2013
CACING TANAH & KUALITAS AIR
Earthworms improve water infiltration and water holding capacity because their shredding, mixing,
and defecating enhances soil structure. In addition, burrows provide quick entry for water into and
through soil. High infiltration rates help prevent pollution by minimizing runoff, erosion, and chemical
transport to surface waters.
There is concern that burrows may increase the transport of pollutants, such as nitrates or pesticides,
into groundwater. However, the movement of potential pollutants through soil is not a straightforward
process and it is not clear when earthworm activity will or will not have a negative impact on
groundwater quality.
Whether pollutants reach groundwater depends on a number of factors, including the location of
pollutants on the surface or within soil, the quantity and intensity of rain, how well water moves into
and through other parts of the soil, and characteristics of the burrows. The horizontal burrows of
endogeic earthworms (such as Aporrectodea tuberculata, which are common in Midwestern fields) do
not transport water and solutes as deeply as the vertical burrows of night crawlers (L. terrestris) and
other anecic species. Even vertical burrows, however, are not direct channels for water movement.
They have bends and turns and are lined with organic matter that adsorbs many potential pollutants
from the water.
Cacing tanah juga membantu meminimumkan pencemaran air permukaan, melalui aktivitasnya yang
dapat memperbaiki laju infiltrasi dan mengurangi runoff.
Diunduh dari: http://soils.usda.gov/sqi/concepts/soil_biology/bacteria.html …………. 20/3/2013
CACING TANAH
Timbunan bahan organik disingkap
menepi untuk membuka lubang
masuk ke liang cacing-tanah.
L. terrestris akan cepat menutupi
kembali liangnya kalau penutup
liangnya tersingkap.
Credit: North Appalachian Experimental
Watershed, USDA-Agricultural Research
Service, Coshocton, Ohio. Please contact the Soil
and Water Conservation Society at
[email protected] for assistance with copyrighted
(credited) images.
Diunduh dari: http://soils.usda.gov/sqi/concepts/soil_biology/bacteria.html …………. 20/3/2013
CACING TANAH
Lubang cacing tanah
membuka, kalau tidak
ada cacing maka
permukaan tanah akan
tertutup oleh kerak
permukaan.
Credit: Clive A. Edwards, The
Ohio State University,
Columbus. Please contact the
Soil and Water Conservation
Society at [email protected] for
assistance with copyrighted
(credited) images.
Diunduh dari: http://soils.usda.gov/sqi/concepts/soil_biology/bacteria.html …………. 20/3/2013
MIKO-RHIZA
Jamur Akar
MIKO-RHIZA
Mycorrhizas are symbiotic associations essential for one or both partners, between a fungus
(specialised for life in soils and plants) and a root (or other substrate-contacting organ) of a
living plant, that is primarily responsible for nutrient transfer. Mycorrhizas occur in a
specialised plant organ where intimate contact results from synchronised plant-fungus
development.
Mycorrhiza merupakan hubungan simbiotik (menguntungkan kedua belah pihak) antara
fungi tanah dan akar tumbuhan.
Two major types of mycorrhiza occur in Nature - endomycorrhiza (common in more than
80 % of terrestrial plant species) and ectomycorrhiza (specific to conifers and some
broadleaved woody species). Endomycorrhizal fungi develop mainly microscopic spores in
the soil whereas most of ectomycorrhizal fungal symbionts develop aboveground fruit
bodies (mushrooms) in the vicinity of trees.
Prinsip dasarnya adalah serupa untuk semua tumbuhan ber-mikorhiza. Kalau akar
tanaman baru sampai kontak dengan inokulum mikorhiza, maka akarnya akan
dikolonisasi dengan hifa fungi dan setelah beberapa minggu tumbuh miselium eksternal yg
meluas ke dalam tanah.
Diunduh dari:
http://www.plantaglobe.com/html/body_types_of_mycorrhizal_symbiosis.HTM
…………. 20/3/2013
MIKO-RHIZA
Apa efek simbiosis mikorhiza terhadap sistem tanah-tanaman?
Increased efficacy of nutrient acquisition, plant growth, flower formation and crop yield.
Enhanced resistance to drought, environmental stress and some root pathogens.
Reduced plant mortality after transplantation.
Improved plant fitness in stressed environment.
Efeknya positif terhadap agregasi tanah dan stabilitas agregat, serta kemampuan tanah
menyimpan air.
Apa keuntungan Mikorhiza?
Sekali aplikasi berfungsi selama siklus bhidupnya tumbuhan.
Mengurangi aplikasi pupuk, biaya pengairan dan biasa pengelolaan
tanaman.
It is compatible with commonly used herbicides and insecticides;
Mycorrhizal plants exploit sources of nutrients in soils at maximum
making it a sustainable approach of cultivation and production
systems when using a minimum of agrochemicals.
Diunduh dari:
http://www.plantaglobe.com/html/body_types_of_mycorrhizal_symbiosis.HTM …………. 20/3/2013
MIKO-RHIZA
Apa nilai komersial dari mycorrhiza?
Mycorrhizas are natural for healthy plants and are rare in disturbed, desertified and
stressed environments. Thus, artificial inoculation with mycorrhizal fungi brings
mycorrhiza to new planted plants and trees in such environments to help them in their
establishment, growth and survival rate.
Suatu tanaman atau pohon yang ber-mycorrhiza mempunyai kapabilitas lebih tinggi untuk
bertahan hidup lebih lama.
Ini merupakan jaminan bagi kesehatan tanaman - sekali perlakuan akan dapat tumbuh
bersama tanaman.
Apakah kendali erosi tanah yang dapat dimediasi oleh mycorrhiza?
Miselum dari jamur mycorrhiza menyebabkan agregasi dan stabilisasi agregat tanah.
Diunduh dari:
http://www.plantaglobe.com/html/body_types_of_mycorrhizal_symbiosis.HTM …………. 20/3/2013
.
Simbiosis Tanaman-Fungi
Mycorrhizas are the most important type of symbiotic plant-fungus associations, but there are a wide
diversity of other associations between plants and fungi, as illustrated in the diagram below. The
relationship between mycorrhizas and other types of plant-fungus associations, such as parasitic or
endophytic associations, are also shown below.
This diagram compares types of plantfungus interactions and each is explained
separately below (after Brundrett 2004).
Mutualistic associations occupy the mutual
benefit (+ +) quadrant in diagrams
contrasting the relative benefits (+) or harm
(-) to two interacting organisms (Boucher
1985, Lewis 1985).
This is a phase plane diagram that describes
biological interactions according to a costbenefit model, where mutualism is an
isocline showing both partners are more
successful together than they are alone
(Boucher 1985, Lewis 1985, Tuomi et al.
2001).
Diunduh dari: http://mycorrhizas.info/#intro…………. 20/3/2013
MIKO-RHIZA
Struktur dan perkembangan hifa mikorhiza mengalami perubahan kalau ada
akar tumbuhan hostnya. Hifa-hifa akar ini bebreda dnegan hifa yang khusus
untuk tumbuh dalam tanah.
All mycorrhizas have intimate contact between hyphae and plant cells in an
interface where nutrient exchange occurs.
The primary role of mycorrhizas is the transfer of mineral nutrients from fungus
to plant. In most cases there also is substantial transfer of metabolites from the
plant to fungus.
Mycorrhizas require synchronised plant-fungus development, since hyphae only
colonise young roots (except orchid mycorrhizas and exploitative VAM).
Tumbuhan mengendalikan intensitas mikorhiza melalui pertumbuhan akarnya,
“mencerna” hifa tua dalam sel-sel tumbuhan (AM, orchid), atau mengubah
bentuk sistem akar (ECM).
Akar-akar berkembang menjadi habitat bagi fungi mikorhiza .
Mycorrhiza biasanya terdapat di akar, tetapi dapat juga host-nya dalam batang
(mis. Beberapa jenis anggrek).
Diunduh dari: http://mycorrhizas.info/#intro…………. 20/3/2013
KATEGORI MIKO-RHIZA
Asosiasi
Kategori
Tipe Morfologi
Asosiasi Mikorhiza
Arbuscular
Asosiasi
Ektomikorhiza
Diunduh dari: http://mycorrhizas.info/#intro…………. 20/3/2013
ARBUSCULAR MYCORRHIZA
Mycorrhizal associations produced by Glomeromycotan fungi are known as
arbuscular mycorrhizas, or vesicular-arbuscular mycorrhizas (formerly also
endomycorrhizas, or endotrophic mycorrhizas) and are abbreviated as VAM here.
There is disagreement about whether arbuscular mycorrhizas or vesiculararbuscular mycorrhizas is the most appropriate name to, because some fungi do
not produce vesicles, but arbuscules are not consistently used to identify
associations (i.e. they are absent in myco-heterotrophs and older roots).
Asosiasi ini melibatkan fungi primitif dalam Glomeromycota dan berbagai jenis
tumbuhan.
Diunduh dari: http://mycorrhizas.info/#intro…………. 20/3/2013
ARBUSCULAR MYCORRHIZA
Struktur dalam Tanah
Hifa
A network of hyphae forms in the soil with thicker
hyphae which function as conduits.
Hifa absorptif
Thin highly branched hyphae which are thought to
absorb nutrients.
Spores Large (for a fungus) asexual spherical
structures (20-1000+ µm diameter) formed on
hyphae in soil, or in roots.
Struktur dalam akar
Hifa : tidak bersekat ketika muda dan tumbuhkembang di dalam korteks.
Arbuscula: Haustoria bercabang-cabang halus
dalam sel-sel korteks akar.
Vesikula: struktur penyimpan yang dibentuk oleh
banyak fungi.
Diunduh dari: http://mycorrhizas.info/#intro…………. 20/3/2013
ARBUSCULAR MYCORRHIZA
Akar mikorhiza dan
hifa-hifanya
merupakan
komponen penting
dalam tanah, tetapi
biasanya tidak dapat
dilihat dengan mata
telanjang.
(they are greatly
exaggerated in this
diagram and soil is
omitted).
Diunduh dari: http://mycorrhizas.info/#intro…………. 20/3/2013
ARBUSCULAR MYCORRHIZA
Hifa Tanah
Asosiasi Mycorrhiza dapat dimulai oleh perkecambahan spora. Hifa juga dapat berasal dari fragmenfragmen akar. In many cases there already is a pre-existing network of hyphae resulting from previous
root activity. Hyphae resulting from spore germination have a limited capacity to grow and will die if
they do not encounter a susceptible root within a week or so. Hyphae emerge from a germination shield
within the spore in Scutellospora and Acaulospora species.
Kecambah hifa yg muncul
beberapa hari setelah spora
diekstraks dari tanah kering.
These spores are of
Gigaspora decipiens (left) and
Scutellospora cerradensis
(right).
Diunduh dari: http://mycorrhizas.info/#intro…………. 20/3/2013
ARBUSCULAR MYCORRHIZA
Soil hyphae, also known as extraradical or
external hyphae, are filamentous fungal
structures which ramify through the soil. They
are responsible for nutrient acquisition,
propagation of the association, spore
formation, etc.
VAM fungi produce different types of soil
hyphae including thick "runner" or
"distributive" hyphae as well as thin
"absorptive" hyphae (Friese & Allen 1991).
Hifa yang halus dapat menghasilkan
"branched absorptive structures" (BAS)
dimana hifa halus tumbuh banyak sekali
(Bago et al., 1998).
Hifa dari spesies Scutellospora dan Gigaspora
menghasilkan “clustered swellings” dengan
duri atau knobs yang disebut sel-sel pengiring.
Diunduh dari: http://mycorrhizas.info/#intro…………. 20/3/2013
ARBUSCULAR MYCORRHIZA
Mycorrhiza yang dibentuk oleh species
Glomus :
1. Relatively straight hyphae ramify
along the root cortex (if root anatomy
permits), often producing "H"
branches which result in simultaneous
growth in 2 directions. Staining of
these hyphae is usually relatively
dark.
2. Arbuscules dapat rtapat dan kompak.
3. Vesikula Oval, yg biasanya terbentuk
di antara sel-sel korteks akar.
Vesikula ini ada dalam akar dan
seringkali mempunyai dinding yg
tebal dan /atau multi-lapisan.
Diunduh dari: http://mycorrhizas.info/#intro…………. 20/3/2013
ARBUSCULAR MYCORRHIZA
Mycorrhiza yg dihasilkan oleh spesies
Scutellospora dan Gigaspora
1. In Scutellospora VAM looping hyphae are
often present near entry points. This genus
has similar root colonisation patterns to
Acaulospora, but hyphae in the cortex are
generally thick-walled and stain darkly.
2. Vesikula Internal tidak ada.
3. Arbuscular trunk hyphae normally are
much longer and thicker than those of
Glomus. Arbuscules appear wispy due to
relatively long curving branches.
4. Pola kolonisasi akar untuk Gigaspora
sangat mirip dengan Scutellospora, hifanya
lebar.
Diunduh dari: http://mycorrhizas.info/#intro…………. 20/3/2013
BAKTERI
RHIZOBIUM
Simbiosis Rhizobium - Legume
Genus Rhizobium, Bradyrhizobium dan Azorhizobium termasuk
famili Rhizobiaceae. Bacteria dari famili ini bersifat Gram-negatif,
aerobik, dan berbentuk batang-motile.
Tumbuhan legume termausk famili Fabaceae. Ini merupakan famili
yang disebut sebagai tumbuhan yang bijinya ada di dalam polong.
N2-fixation by rhizobium occur when the bacteria live symbiotically
in nodules on roots of the leguminous host plant.
Diunduh dari: http://www.vaxteko.nu/html/sll/slu/rapport_mikrobiologi/RMB65/RMB65.HTM …………. 20/3/2013
Bakteri simbiotik Bintil-akar
Rhizobium membentuk bintil dan bekerja dalam fiksasi nitrogen secara
simbiotik.
The rod – shaped bacteria, utilize organic acid salts as carbon source without gas
formation; while the cellulose and starch are not utilised.
The growth is optimum at 27˚C (pH 6.8) and colonies appeared as circular convex
semitranslucent, raised and mucilagenous, usually 2-4 mm in diameter. Production
of an acid reaction occurs in mineral salt medium.
Some strains of rhizobia and agrobacteria show a close relationship in D.N.A. base
composition. All species (except Agrobacterium radiobacter ) incite hypertrophies
on plant roots.
Nodules are incited by strains of rhizobia on roots of leguminous palnts and leaves
of certain plants in the families Myristicaceae and Rubiaceae by strains of
Phyllobacteria.
Diunduh dari:
http://dushyantraj.wordpress.com/2008/10/30/nitrogen-fixation/…………. 20/3/2013
Asosiasi Rhizobium-Tanaman (van Rhijn & Vanderleyden 1993).
Rhizobium
Host plant(s)
Rhizobium meliloti
Medicago, Melilotus and Trigonella spp.
Rhizobiumle guminosarum
bv. viciae
bv. trifolii
bv. phaseoli
Rhizobium loti
Rhizobium haukuii
Rhizobium ciceri
Pisum, Vicia, Lathyrus and Lens spp.
Trifolium spp.
Phaseolus vulgaris
Lotus spp.
Astragalus sinicus
Cicer arietinum
Rhizobium tropici
Phaseolus vulgaris, Leucaena spp., Macroptilium spp.
Rhizobium etli
Rhizobium galegae
Phaseolus vulgaris
Galega officinalis, G. orientalis
Rhizobium fredii
Glycine max, G. soja and other legumes
Bradyrhizobium japonicum
Glycine max, G. soja and other legumes
Bradyrhizobium elkanii
Glycine max, G. soja and other legumes
Bradyrhizobium sp. strain
Parasponia
Azorhizobium caulinodans
Parasponia. spp.
Sesbania spp. (stem nodulating)
Diunduh dari: http://www.vaxteko.nu/html/sll/slu/rapport_mikrobiologi/RMB65/RMB65.HTM…………. 20/3/2013
Tahapan dalam proses infeksi oleh bakteri Rhizobium. Molecules possibly involved in the various steps
are indicated. The order in which the steps are drawn is not necessarily the order in the nodulation
process. (Smit et al. 1992.) .
Infeksi Bakteri dan Perkembangan Bintil
The nodulation process is controlled by genetic
information from both symbionts. The infection
and development of root nodules can be divided
into several steps .
First there is a recognition of both symbionts,
then the bacterium attaches to the root hair. The
root hair is curled to facilitate the bacterium´s
entry into the root hair. There is a formation of
an infection tread in which the bacterium moves
towards the main root. The nodule is initiated
and vegetative bacterial cells are transformed to
enlarged pleomorphic forms called bacteroids
which fix N.
Tanaman menghasilkan leghaemoglobin untuk
melindungi ensim fiksasi N2 enzyme,
nitrogenase, yg sangat peka terhadap oksigen.
Adanya leghaemoglobin menimbuylkan bintil
warna merahmuda (Sprent & Sprent 1990, van
Rhijn & Vanderleyden 1995).
Diunduh dari: http://www.vaxteko.nu/html/sll/slu/rapport_mikrobiologi/RMB65/RMB65.HTM…………. 20/3/2013
Fiksasi N2 dan Aktivitas Nitrogenase
Diagram interaksi antara fiksasi
N2, NO3- dan reduksi NO2-, dan
asimilasi NH4+ dalam bintil akar
legume.
Garis putus-putus menyatakan
tahapan yg tidak penting.
Ensim dalam bacteroids:
(1) N2-ase, (2) NR, (3) NiR, (4)
NO-reductase and (5) N2Oreductase.
Ensim dalam biltil fraksi
tumbuhan: (6) NR, (7) NiR, (8)
glutamine synthetase (GS), and
(9) glutamate synthase (GOGAT).
(Becana & Sprent 1987.)
Diunduh dari: http://www.vaxteko.nu/html/sll/slu/rapport_mikrobiologi/RMB65/RMB65.HTM…………. 20/3/2013
Infeksi legume oleh Rhizobium leguminosarum.
a. Fase awal
infeksi bulu akar
oleh rhizobia dan
pertumbuhan
bintil pada akar.
Diunduh dari: http://www.nature.com/nrm/journal/v5/n7/fig_tab/nrm1424_F1.html…………. 20/3/2013
Interaksi antara Legume dengan Rhizobia.
Legume plants form
nitrogen-fixing nodules in
the symbiosis with soil
bacteria of the genera
Rhizobium,
Bradyrhizobium,
Azorhizobium,
Mesorhizobium and
Sinorhizobium.
Inisiasi proses pembentukan
bintil:
Deformasi bulu akar
Pembentukan benang infeksi
Pembelahan sel korteks
Interaksi bakteri
rhizobium dengan
tumbuhan legume
dikendalikan oleh
keunikan tumbuhan
hostnya.
Tumbuhan inang (host)
Diunduh dari: http://www.glycoforum.gr.jp/science/word/saccharide/SA-A02E.html…………. 20/3/2013
Membran luar Rhizobium dan Simbiosis dengan tanaman
Pengenalan bahan
kimia
Legume menyediakan
sumber C bagi Rhizobia.
Rhizobia menyediakan
NH4+ bagi legume
Deformasi bulu akar
dan pembelahan sel
akar
Pembentukan benang
infeksi
Pembentukan jaringan bintil
dan diferensiasi bakteroid.
Sintesis nitrogenase dan
leghemoglobin
Bakteri Gram-negatif,
seperti Rhizobium etli dan
Rhizobium
leguminosarum, termasuk
pada famili mikroba yang
memfiksasi nitrogen
selama simbiosis di dalam
akar tumbuhan legume.
Stages in the biology of the
nodulation process.
Mutants of R. etli and R.
leguminosarum lacking Oantigen are arrested in the
late steps of nodule
development.
Diunduh dari: http://www.biochem.duke.edu/modules/biochem_raetz_lab/print.php?id=6…………. 20/3/2013
Membran luar Rhizobium dan symbiosis dg tumbuhan.
Topografi membran
symbiosome.
The intimate contact of the
Rhizobium outer membrane
with the plant peri-bacteroid
membrane could involve
remodeling of specific
membrane proteins and lipids.
Diagram adapted from Whitehead
and Day, Physiologia Plantarum
100, 30-44, 1997.
Diunduh dari: http://www.biochem.duke.edu/modules/biochem_raetz_lab/print.php?id=6…………. 20/3/2013
Kekhususan Rhizobia untuk keberhasilan nodulasi legume tertentu.
Diunduh dari: http://www.ctahr.hawaii.edu/mauisoil/c_nutrients01.aspx…………. 20/3/2013
Pengukuran fiksasi nitrogen secara biologis oleh berbagai jenis legume
Diunduh dari: http://www.ctahr.hawaii.edu/mauisoil/c_nutrients01.aspx…………. 20/3/2013
Bintil akar yg mengandung Rhizobium.
Bintil akar berisi bakteri Rhizobium
http://www.mokkka.hu/drupal/en/node/2901
Diunduh dari:
http://faculty.ksu.edu.sa/shoeib/Pictures%20Library/Forms/DispF
orm.aspx?ID=447&RootFolder=%2Fshoeib%2FPictures%20Libr
ary%2Frhizobium…………. 20/3/2013
Proses pembentukan bintil akar
‘rhizobia’ hidup bebas dalam tanah, dan segera setelah kontak dengan host yang sesuai, ia memulai
proses infeksi. Ada kontak initial antara bacteria dan host , tergantung pada pengenalannya.
Bulu akar normal
↓
Exudation of organic substances by
roots
↓
Accumulation of ‘rhizobia’ in the
rhizosphere
↓
Conversion of tryptophan to IAA
↓
Bulu akar melengkung dan berubah
bentuk
Infeksi bulu akar untuk pembentukan bintil
(nodul)
Diunduh dari:
http://dushyantraj.wordpress.com/2008/10/30/nitrogen-fixation/…………. 20/3/2013
BINTIL AKAR
The nitrogen-fixing
nodule hosts symbiotic
Rhizobium bacteroids,
which function as
specialized nitrogen
fixing organelles that
exchange fixed
nitrogen for
photosynthates.
Diunduh dari:
…………. 20/3/2013
….. dan selanjutnya ………..
Foto: smno.tanahsawah.caruban.nop2012