BIOA02H3 Lecture Notes - Lecture 11: Humus, Bioavailability, Meristem

• School: UTSC
• Department: Biological Sciences
• Course: BIOA02H3
• Professor: Ivana Stehlik

Document Summary

Carbon, oxygen, and hydrogen comprise 95% of plant dry mass. Macronutrients: required in relatively large amounts (n,p,ca, mg, p,s, si) Not having essential nutrients inhibits plant from completing its life cycle. Is the essential building block for life has bioavailability through nitrogen fixing bacteria. Young soils are ones that have limited nitrogen levels (eg. sand dunes, newly deglaciated areas, volcanic islands) Nitrogen use: photosynthesis, atp, nadp, nucleic acids. Athmopshere is major nitrogen source n2 becomes available in soil w/o bacteria through lightning strikes makes nitrate (the bio- accessible form of nitrogen) Promotes early plant growth and root formation -> role in cell division (for meristem tissue) Low bioavailability in soils: p is highly reactive and precipitates easily. Important in process of sugar and starch production (after photosynthesis) Increase plant diseases resistance, assists in enzyme activation and photosynthesis. Bioavailbility: relatively immobile in soils (tied to soil particles) Soils high in clay/humus have lots of vely charged.