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Hery Purnobasuki
 2008
• A variety of physical processes of transportation in plant
– Are involved in the different types of transport
4 Through stomata, leaves
take in CO2 and expel O2.
The CO2 provides carbon for
photosynthesis. Some O2
produced by photosynthesis
is used in cellular respiration.
CO2
O2
5 Sugars are produced by
photosynthesis in the leaves.
Light
H2O
Sugar
3 Transpiration, the loss of water
from leaves (mostly through
stomata), creates a force within
leaves that pulls xylem sap upward.
6 Sugars are transported as
phloem sap to roots and other
parts of the plant.
2 Water and minerals are
transported upward from
roots to shoots as xylem sap.
1 Roots absorb water
and dissolved minerals
from the soil.
O2
H2O
Minerals
CO2
7 Roots exchange gases
with the air spaces of soil,
taking in O2 and discharging
CO2. In cellular respiration,
O2 supports the breakdown
of sugars.
6.9
Casparian strip
Lateral transport
of minerals and
water in roots
1
Endodermal cell
Pathway along
apoplast
Pathway
through
symplast
Uptake of soil solution by the
hydrophilic walls of root hairs
provides access to the apoplast.
Water and minerals can then
soak into the cortex along
this matrix of walls.
Casparian strip
2 Minerals and water that cross
the plasma membranes of root
hairs enter the symplast.
1
Plasma
membrane
Apoplastic
route
Vessels
(xylem)
2
3
As soil solution moves along
the apoplast, some water and
minerals are transported into
the protoplasts of cells of the
epidermis and cortex and then
move inward via the symplast.
Symplastic
route
Root
hair
Epidermis
4
5
Within the transverse and radial walls of each endodermal cell is the
Casparian strip, a belt of waxy material (purple band) that blocks the
passage of water and dissolved minerals. Only minerals already in
the symplast or entering that pathway by crossing the plasma
membrane of an endodermal cell can detour around the Casparian
strip and pass into the vascular cylinder.
Cortex
Endodermis
Vascular cylinder
Endodermal cells and also parenchyma cells within the
vascular cylinder discharge water and minerals into their
walls (apoplast). The xylem vessels transport the water
and minerals upward into the shoot system.
• Water and minerals can travel through a
plant by one of three routes
– Out of one cell, across a cell wall, and into
another cell
Key
– Via the symplast
Symplast
– Along the apoplast
Apoplast
Transmembrane route
The symplast is the
continuum of
cytosol connected
by plasmodesmata.
Symplastic route
Apoplast
Symplast
The apoplast is
the continuum
of cell walls and
extracellular
spaces.
Apoplastic route
Transport routes between cells. At the tissue level, there are three
(b) passages:
the transmembrane, symplastic, and apoplastic routes. Substances
may transfer
from one route to another.
Figure 36.8b
Teori tentang
transport air
dalam
tanaman
1. Teori vital
2. Tekanan akar
3. Hukum kapilaritas
4. Teori kohesi
5. Transpirasi
Transpiration
• Transpiration is the loss of water from a plant by
evaporation
• Water can only evaporate from the plant if the
water potential is lower in the air surrounding the
plant
• Most transpiration occurs via the leaves
• Most of this transpiration is via the stomata.
Ψtanah > Ψakar > Ψbatang > Ψdaun > Ψudara
PENGUKURAN TRANSPIRASI
1. Kertas Cobalt Chlorida
2. Fotometer
3. Pengumpulan uap air
4. Penimbangan Langsung
Pengukuran transpirasi menurut
Salisbury & Ross (1991)
Lysimeter / Gravimetric Method
- Pengukuran langsung
Gas exchange / Cuvette Method
- Pengukuran uap air
Stem-Flow Methods
How Transpiration is Measured
Water evaporates
from the plant
A Simple
Potometer
Leafy shoot cut
under water
Air tight seals
Capillary tube
Plastic tubing
1’’’’’’’’2’’’’’’’’3’’’’’’’’4’’’’’’’’5’’’’’’’’6’’’’’’’’7’’’’’’’’8’’’’’’’’9’’’’’’’’10’’’’’’’’11’’’’’’’’12’’’’’’’’13’’’’
Graduated scale
Movement of meniscus is
measured over time
The rate of water loss
from the shoot can be
measured under different
environmental conditions
Water is pulled up
through the plant
volume of water taken up
in given time
Limitations
•measures water uptake
1’’’’’’’’2’’’’’’’’3’’’’’’’’4’’’’’’’’5’’’’’’’’6’’’’’’’’7’’’’’’’’8’’’’’’’’9’’’’’’’’10’’’’’’’’11’’’’’’’’12’’’’’’’’13’’’’
•cutting plant shoot may damage plant
•plant has no roots so no resistance to water being pulled up
Tipe transpirasi:
1. Transpirasi
kutikula
- 10% atau kurang dari
jumlah air yang hilang
2. Transpirasi stomata
3. Transpirasi lentisel
Water and Mineral
Movement
• Regulation of transpiration
– Stomata open and close due to
changes in turgor pressure of
guard cells.
• Turgor results from active uptake of
potassium (K+) ions.
– Increase in K+ concentration creates a
water potential that causes water to
enter osmotically, guard cells to
become turgid, and stomata to open.
The guard cells control the opening and
closing of the stomata
Guard cells flaccid
Guard cells turgid
Thin outer wall
Thick inner wall
Stoma closed
Stoma open
Regulating Stomatal Opening:-the
potassium ion pump hypothesis
Guard cells flaccid
K+
K+ ions have the same
concentration in guard cells
and epidermal cells
K+
K+
K+
K+
K+
K+
K+
K+
K+
Stoma closed
K+
K+
Light activates K+ pumps
which actively transport K+
from the epidermal cells
into the guard cells
Regulating Stomatal Opening:-the
potassium ion pump hypothesis
H2O
H2O
K+
H2O
K+
K+
K+
H2O
K+
K+
Increased concentration
of K+ in guard cells
K+
K+
H2O
K+
K+
K+
K+
Lowers the  in the
guard cells
Water moves in by
osmosis, down  gradient
Guard cells turgid
H2O
K+
K+
H O
2
K+
K+
H2O
K+
Increased concentration of K+
in guard cells
H2O
K+
K+
Lowers the  in the guard
cells
H2O
K+
K+
H2O
K+
Stoma open
K+
K+
Water moves in by osmosis,
down  gradient
Some other facts about the
stomata
• Open in the day and closed at night - need
carbon dioxide in the daylight for
photosynthesis
• When water is scarce, plant wilts and guard
cells become flacid
• Abscisic acid - plant hormone that causes K+ to
pass out of cells and guard cells become flacid
• High levels of CO2 cause guard cells to become
flacid
• Leaves lost when water is scarce
6 Environmental Factors Affecting Transpiration
1. Relative humidity:- air inside leaf is saturated (RH=100%).
The lower the relative humidity outside the leaf the faster the
rate of transpiration as the  gradient is steeper
2. Air Movement:- increase air movement increases the rate of
transpiration as it moves the saturated air from around the leaf
so the  gradient is steeper.
3. Temperature:- increase in temperature increases the rate of
transpiration as higher temperature
– Provides the latent heat of vaporisation
– Increases the kinetic energy so faster diffusion
– Warms the air so lowers the  of the air, so  gradient is
steeper
4. Atmospheric pressure:- decrease in atmospheric pressure increases the rate of
transpiration.
5. Water supply:- transpiration rate is lower if there is little water available as
transpiration depends on the mesophyll cell walls being wet (dry cell walls have a
lower ). When cells are flaccid the stomata close.
6. Light intensity :- greater light intensity increases the rate of transpiration because
it causes the stomata to open, so increasing evaporation through the stomata.
Intrinsic Factors Affecting the
Rate of Transpiration.
1. Leaf surface area
2. Thickness of epidermis
and cuticle
3. Stomatal frequency
4. Stomatal size
5. Stomatal position
Nama Tanaman
Banyaknya stoma per mm2
pada permukaan
atas
bawah
Polypodium nidus (Paku Pandan)
0
85
Gnetum gnemon
0
335
Rhoeo discolor
0
30
Gloriosa superba
0-1
120
Zephyranthes rosea
70
50
Typha domingensis
350
560
0
250
Imperata cylindrical
320
340
Alpenia galangal (Lengkuas)
0-2
200
Phalaenopsis amabilis
10
30
Ficus elastica
0
200
Helianthus annuus
210
250
Lycopersicum esculentum
130
2E
Zea mays
68
52 E
Solanum tuberosum
161
51 M
Begonia coccinea
40
0E
Coleus blumei
141
0E
Pelargonium domesticum
59
19 E
Areca catecha
Jenis tanaman berdasarkan kondisi air di habitatnya:
1. Tanaman air (hidrofit)
2. Tanaman daerah basah (higrofit)
3. Tanaman daerah sedang (mesofit)
4. Tanaman daerah tropis (tropofit)
5. Tanaman daerah kering (xerofit)
Jenis tanaman pada tanah yang kurang air
1. Efemera
Tumbuh sebentar, di gurun-gurun
2. Sukulenta
Berdaun tebal, berlapis lilin, sedikit stoma, stoma tersembunyi,
banyak akar
Cactaceae, Euphorbiaceae, Liliaceae, Amaryllidaceae,
Crassulaceae dan Aizoaceae
3. Xerofit
Tahan kekeringn dan akar panjang (+30 m)
Adaptations to reduce transpiration loss in plants growing in dry
conditions (xerophytes)
Thick cuticles - prevent water loss from epidermal cells
Succulent (thick) leaves - store water
Loss of leaves/reduction of leaves to form spines - light is not limiting, so
photosynthesis can be carried out by the shoot. What type of plant am I describing?
White leaves/spines - light colors reflect light and heat, thereby cooling the plant
Trichomes (hairs) - create a more humid microenvironment to reduce evaporative
water loss
Sunken stomates - like trichomes, a more humid microenvironment is created
CAM photosynthesis - stomates open during the night (when it is cooler) and fix
CO2 into four-carbon acids
The light reaction occurs during the day, generating NADPH and ATP
Rolled leaves:- this reduces the area exposed to the air and keeps the stomata on the
inside so increasing the water vapour inside the roll
Peranan Transpirasi
Merupakan proses pendinginan (daun)
Pemindahan panas
Mempengaruhi keadaan sekitar
Bagian dari siklus air
Contoh perubahan energi dalam ekosistem:
Padang Pasir
Suhu , radiasi , kelembaban , air 
Mengatur kelembaban dan menjaga suhu rendah daun
Daun kecil, lapisan pembatas sel tipis, transfer panas efektif
Alpine Tundra
Dingin, cukup lembab, radiasi , air cukup
Rata-rata suhu daun 30oC (> suhu udara)
Transpirasi tak bermanfaat
Catatan: rumus-rumus keseimbangan panas pada daun dapat dibaca di Salisbury &
Ross (1991), Plant Physiology.
Jenis air dalam tanah:
1. Air kimia
2. Air higroskopik / hidrasi
3. Air gravitasi
4. Air kapiler
GUTASI
Penetesan /pengeluaran
air melalui lubang-lubang
di tepi daun
Berlangsung pada malam
hari
Lubang-lubang tersebut 
hidatoda (emisaria)
dimana terdapat jaringan
epitema di dalamnya
Terjadi karena adanya tekanan akar dan faktor
lainnya
Aktifitas
pengukuran laju
transpirasi pada
tanaman
SOAL
1. Apakah pengaruh transpirasi pada peresapan air oleh akar?
2. Bagaimana cara kita membuktikan bahwa lalu lintas dalam pembuluh kayu
(xilem) itu tidak satu jurusan saja?
3. Bagaimana teori kohesi mendukung transport air dalam tanaman? Dan
bagaimana hubungannya dengan transpirasi?
4. Mengapa transpirasi melalui kutikula lebih sedikit dibandingkan dengan
stomata? Bagaimana cara membuktikannya?
5. Jelaskan faktor-faktor yang dapat mempengaruhi proses transpirasi?
6. Jelaskan faktor-faktor yang dapat mempengaruhi proses gutasi? Dan
apakah perbedaan gutasi dan transpirasi?