Bio 1150 1st Edition Lecture 25Current LectureTopic Discussed: Soil and Plant NutritionPlant nutrients= minerals- iron, nitrogen, etc.Soil is separated into horizons- Topsoil (A horizon) -organic humus- Loams -most fertile, equal mixture of sand, silt and clay- Deeper soil= less nutritions (lighter color)Roots use cation exchange to release nutrients- Ions vary in their degree of attraction to soil particlesSoil- composed of dirt, animals, fungi, microbes and insectsPlants require essential elements to complete their life cycle- Macronutrients- needed in large amountso C, O, H, N, P, S, K, Ca, Mg- Micronutrients -needed in small amountso CL, Fe, Mn, Bo, Zn, Cu, Ni, Mo and sometimes Nao Are cofactors or catalysts in biochemical reactionsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.o K is important for osmoregulationHydroponics- used for studying nutrient deficiency- Roots have to be oxygenatedHealthy leaf- green- Phosphate deficient leaf- purple- Potassium deficient- yellow/ brown edges- Nitrogen deficient- yellow/ brown tipBacteria and nitrogen- Nitrogen is in the air, but is highly oxidized- Nitrogen fixing bacteria- can break the nitrogen-nitrogen triple bond- Ammonifying bacteria- takes organic material and make NH3 with nitrogen fixing bacteria- An H+ is added and turns NH3 into NH4- Nitrifying bacteria makes NO3-- Plants use NO3 - Denitrifying bacteria turns the remainder into N2Rhizobium forms an association with legume plants, forming nodulesFlavonoids- group of compounds, made by plantsNod factor- signals, sent by bacteria Leghemoglobin- binds oxygen, and keeps it away from enzymatic reactionsMycorrhizal fungi- mutualism between plants and fungiEctomycorrhizae- in trees, like pine, oak, walnutEndomycorrhizae-- Most common; in 85% of all plant species- Arbuscular mycorrhizae- arbuscules are growths in plants- look like a tree- Mostly beneficialPlants that do not rely on mycorrhizae- Mustards, broccoli, kale, cabbageEpiphytes - absorb water and nutrients from rain through leaves, no roots, “air” plantsParasitic Plants- mistletoe, dodder, indian pipe- Haustoria ( in mistletoe and dodder)- how they attach to host plants- Indian pipe- taps into mycorrhizae of plantsCarnivorous Plants- Pitcher plants- drown insects- Sundews- produce very sticky substance that looks like nectar- Venus flytrap- All of these are leaf
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