Plant Nutrition Flashcards
Plants require macronutrients and micronutrients for what?
Their metabolism.
Why are essential elements important?
- necessary for normal growth and development
- cannot be functionally replaced by a different element
- has one or more roles in plant metabolism
What are the nine essential macronutrients?
C, H, O, N, Ca, Mg, K, P, S
What percent of dry mass comes from air and water?
roughly 96%
Micronutrients are essential in what trace quantity?
<200 ppm
What are the micronutrients?
Ni, Cu, Mo, Mn, Zn, Fe, Cl, B
What is chlorosis?
Loss of green colouration
Roots also secreting substances into the soil helps us understand what?
How plants adapted to obtain nutrients and fight disease
Mycorrhizae and nitrogen-fixing bacteria are both…
Adaptive interactions that increase plant access to scarce nutrients.
Characteristics of roots:
- Makeup 20-50% of total plant mass
– Roots grow continuously
Roots mechanisms to increase uptake
- Root hairs
– Membrane transporters
– Mycorrhizae
Is transpiration active or passive?
Passive
Some mineral ions enter root cells immediately through this route…
Symplastic route
Some minerals travel between cells until they meet the endodermis…
apoplastic route
inside most cells minerals enter:
vacuoles or cell cytoplasm
some ions move through:
the phloem
Nitrogen is:
– Abundant element in air, most limiting to plant
– Triple bond requires nitrogenase enzyme
– Nitrogen cycle provides soil nitrogen
Nitrogen fixation does what?
incorporates atmospheric N2 into plant-available compounds (ammonum)
What is the Haber-Bosch Process?
an industrial process for producing ammonia from nitrogen and hydrogen, using an iron catalyst at high temperature and pressure.
What does the Haber-Bosch process depend on?
Petroleum
By what percent did the Haber Bosch process increase the population?
40%
Most nitrogen is fixed by what?
plant symbioses with bacteria
How are plants and bacteria mutally beneficial?
Plant provides organic molecules for
respiration energy, bacteria provide NH4+
Legumes form root nodules with:
Rhizobium or
Bradyrhizobium
How are bacterial nod genes expressed?
with flavonoid signal from plants
Infection thread allows for what?
Bacterial invasion
Bacteroids are…
enclosed in nodule and are integrated into the root system
Examples of atypical nutrient aquisision:
Cobra lily, Dodder, Snow plant, Lady-of-the-night orchid
What take only physical support from host plants?
Epiphytes
