Download Chapter 38 Plant Nutrition - Tri

Chapter 37 Plant Nutrition
Biology 102
Tri-County Technical College
Pendleton, SC
Macro versus Micronutrients
Macronutrient is nutrient required by plant in
large amounts
Micronutrient is nutrient required by plant in
small amounts
Micronutrients:
Carbon (CO2)-major component of plant’s
organic compounds
Oxygen (CO2)-major component of plant’s
organic compounds
Macronutrients, cont.
Hydrogen (H2O)-major component of
plant’s organic compounds
Nitrogen (NO3-; NH4+)-component of
nucleic acids, proteins, hormones, and
coenzymes
Sulfur (SO42-)-component of proteins &
coenzymes
Macronutrients, cont.
Phosphorous (H2PO4-; HPO42-)-component of
nucleic acids, phospholipids, ATP, & several
coenzymes
Potassium (K+)-cofactor that functions in
protein synthesis, major solute functioning in
water balance, & operation of stomata
Calcium (Ca2+)-formation and stability of cell
walls, maintenance of membrane structure
and permeability, activates some enzymes,
regulates many responses of cells to stimuli
Macro and Micro
Magnesium (Mg2+)-component of
chlorophyll, activates many enzymes
MICRONUTRIENTS:
Chlorine (Cl-)-required for watersplitting step of photosynthesis,
functions in water balance
Iron (Fe3+; Fe2+)-component of
cytochromes, activates some enzymes
Micronutrients, cont.
Boron (H2BO3-)-cofactor in chlorophyll
synthesis, may be involved in carbohydrate
transport and nucleic acid synthesis
Manganese (Mn2+)-active in formation of
amino acids, activates some enzymes,
required for water-splitting step of
photosynthesis
Zinc (Zn2+)-active in formation of chlorophyll
and activates some enzymes
Micronutrients, cont.
Copper (Cu+; Cu2+)-component of many
redox and lignin-biosynthetic enzymes
Molybdenum (MoO42-)-essential in
nitrogen fixation and cofactor that
functions in nitrate reduction
Nickel (Ni2+)-cofactor for enzyme
functioning in nitrogen metabolism
Micronutrient Why’s?
Most micronutrients function as
cofactors of enzymatic reactions
Because micronutrients generally play
catalytic roles that plants need only
minute quantities of these elements
Example: only 1 molybdenum atom for
each 16 million atoms of hydrogen in
dried plant material
Plants and Nitrogen
Plants require nitrogen to produce proteins,
nucleic acids, and other organic molecules
They CANNOT use nitrogen in gaseous form
(N2)
To be used, must be in form of ammonium
(NH4+) or nitrate (NO3-)
Plants acquire most of their nitrogen in the
form of nitrate (NO3-)
Plants and Nitrogen, cont.
Nitrate produced in soil by nitrifying
bacteria

They oxidize ammonia/ammonium
Other species of nitrogen fixing bacteria
live in plant roots (mutualistic symbiotic
relationship)
Nitrogen absorbed by plant is
incorporated into organic compounds
Nitrogen Cycle Visual
Miracle Grow or thereabouts…
Ever purchase a bag of triple 13?
No, how about triple 10?
13-13-13 or 10-10-10

Not brain surgery…is by weight so close
Lists contents in order of: Nitrogen,
phosphorous, and potassium
N-P-K
21-0-0 (Oh yeah…but….)
Nitrogen Fixation
Few species of bacteria possess enzyme that
will convert nitrogen gas to ammonia (N2
NH3)


Essential to life on this planet
Cyanobacteria and Rhizobium
Rhizobium “infects” roots of plants causing
nodulation

These nodes are site of bacteria nitrogen fixing
Knowing the Nodes
Nitrogen Fixation Visual
Bits and Pieces…
Mutualistic symbiotic relationship
Mycorrhizae is mutualistic relationship
between fungus and plant roots
Increases absorption of water and
minerals (especially phosphorus)
Can be ECTO or ENDO
(This should be a review from Bio 101)
Heterotrophic/Carnivorous
Plants
Some plants have lost ability to sustain
themselves by photosynthesis



Mistletoes, dodders, and Indian pipe
Kind of ify for mistletoe but….
Extract nutrients from hosts by absorptive
organs called haustoria
Approximately 450 plant species are
carnivorious
H/C Plants, cont.
Do not live by photosynthesis alone

Venus fly trap, sundews, & pitcher plants
Most live in acidic environments


Difficult for decay-causing organisms to break
down bodies of dead organisms
Hence, not much recycling
These plants evolved way to supply their
nitrogen (and phosphorous) needs by “eating
protein”