Chapter 37: Soil and Plant Nutrition Flashcards
Soil is created by an interaction of ____ and ____ factors.
biotic, abiotic
Topsoil
a mixture of particles from rock, living organisms, and humus
contains macronutrients, micronutrients, and water
Plants are made of 80-90%….
Water
Carbohydrates
composed of C, H, O in a ratio of 1:2:1
Example: glucose, fructose
Lipids
composed of C, H, O but have fewer O than carbohydrates.
Example: steroids, fats
Proteins
composed of C, H, O and N (nitrogen)
Example: hemoglobin, enzymes
Nucleic acids
composed of C, H, O, N, and P (phosphorus)
Example: DNA, RNA
Macronutrients
nutrients that plants require in large quantities in order to survive including C, O, H, N, P, S, K, Ca, Mg
Micronutrients
nutrients that plants require in small quantities in order to survive including Cl, Fe, Mn, Bo, Zn, Cu, Ni, Mb
*Micronutrients are not broken down, but instead are used intact and are required for enzyme functioning or the synthesis of specific proteins
Essential elements
any chemical element that is required by plants to survive; includes both macronutrients and micronutrients
Nitrogen
Key nutrient for leaf growth
Phosphorus
Favors development of flowers and fruits
Potassium
Increases stress tolerance and builds strong roots
Humus
partially decayed organic matter in soil
Loam
soils with sand, silt and clay particles all present in intermediate amounts
Cation exchange
the process by which positively charged ions (cations) are replaced on the surfaces of soil particles
by H+ thereby making those ions available for uptake by plants
2 forms of nitrogen that plants can use
ammonium & nitrate
Rhizobium bacteria
move into the cells of the root cortex, causing the cells of the root to begin dividing and producing a knob or nodule round the site of infection
Symbiotic Rhizobium Bacteria environment must be…
anaerobic
2 types of Symbiotic Fungi
Ectomycorrhizae & Endomycorrhizae
Benefit to the plant in Symbiotic Rhizobium Bacteria
ammonium produced by the rhizobium is converted into amino acids in the root cortex and exported to the rest of the plant body
Benefit to the rhizobium in Symbiotic Rhizobium Bacteria
carbohydrates produced by the photosynthesizing plant are needed by the bacteria to carryout energetically expensive N-fixation
Benefit to the plant (mycorrhizae)
increased rate of uptake of soil resources, especially P
Benefit to the fungi (mycorrhizae)
carbohydrates produced by the photosynthesizing plant