Plants Theme 4 Flashcards
Homeostasis
Dynamic process compensating for changes in the internal and external environment
What are the essential elements for plants?
Nucleic acids (N & P), amino acids (N & S), enzyme cofactors (Ca), photosynthesis (Mg, Fe), regulation of osmosis (K)
How many essential elements are there for plants?
17
What are the essential macronutrients for plants
C, H, O (from water), N, P, K, Ca, Mg (mineral nutrients, must be dissolved in water)
What are the essential micronutrients for plants
Cu, Cl, Ni (trace quantities)
How much of the atmosphere is composed of nitrogen
78%
incorporates atmospheric N into plant available compounds NH4
nitrogen fixation
What happens in ammonification?
Bacteria breaks down decaying organic N into NH4
Which type of N is prefered by plants
NO3, but can take up NH4
What is the process of oxidizing NH4 into NO3
nitrification
Which form of nitrogen is moved via xylem in shoot system
NH4
Who was credited with saving a billion lives from starvation
Borlaug, green revolution
What is Eutrophication?
Enrichment of an ecosystem with chemical nutrients with N & P, caused by fertilizer runnoff
What is chlorosis?
Yellowing of plant tissue due to lack of chlorophyll
What does Humus do?
decomposing organics, holding water and nutrients in the top soil
What is the cation exchange?
mineral cations (Mg, Ca, K) adsorb to negative soil particles
What are the two cation exchange processes?
cellular respiration, where H from carbonic acid replaces mineral cations in soil.
Root hair, where H from the root hairs replaces mineral cations in soil.
Both allow for the uptake of minerals (Ca, K, Mg)
How do plants take in iron
extracted from the soil
What is the rough pH and charge of clay
Alkaline (basic-high pH) and negatively charged
Alkaline soils
anions leach out easily
acidic soils
cations leach out easily
Passive transport
No energy, down/with a concentration gradient
Active transport
requires energy, against gradient
What is Mycorrhizae
The symbiotic association between fungus and plants roots
What increases the plants’ supply of soil nutrients and what is the main nutrient
fungus, P
What do root nodule bacteria do?
nitrogen fixation
What are the conditions required for iron to be taken up by plants?
lower pH and made soluble
What is the water potential of solutes?
always negative
What is the water potential of pure water
0 Mpa