BIOA02H3 Lecture Notes - Lecture 10: Stoma, Biogenic Substance, Dune
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January 7th~Feb1 2013
Midterm date: Monday Febuary 4th 2013. 5-7pm
Module 2: Begins on Tuesday Feb 5th.
Total: 12 lectures
1-2: Tree of life-plants
3-4 Plant cells and plant tissues
5-6. From seed to tree
7-8. From tree to seed
9. Transport in plants
10. Plant nutrition and soils
11. Plant defense
12. Plant life on the edge.
Lecture 10 notes (Plant nutrition & soils)
A) Nutrients necessary for plant life
Sugar: carbon dioxide & light & water
Water & oxygen
From high elements needed to low elements needed
then macronutrient:N>K>Ca>Mg>P>S>Si. Required in large amounts
Then micronutrient: Cl>Fe>B>Mn>Na>Zn>Cu>Ni>Molybdenum(mo)
required in smaller amounts
Absence prevents plant from completing its life cycle
Most limiting under average condition: N,P,K
Dunes lack N=no plant growth
When ice melt, there is no bacteria in the sugar=no N=no plant growth
Essential building block for life, basic metabolism, photosynthesis
Atmospheric overabundance (78% nitrogen gas)
Bioavailability through bacteria.
Young soils (dune, volcanic soil, ice glaciers) limit N until bacteria build up.
Building blocks of life: amino acid into protein
Glycine, Alanine, Serine, Threonine, Cysteine, valine, leucine, isoleucine, methionine,
proline, phenylalanine, tyrosine, tryptophan, apsartic acid, glutamic acid,
asparagine, glutamime. Histidine, lysine, arginine. (C,H,O,N elements)
N present in:
Photosynthesis: chlorophyll A-H3C. chlorophyll B: COOH
Energy currency: NADP
Inheritance: nucliec acids. ATCG
so let’s start with
atmosphere nitrogen gas. Nitrogen gas has 3 ways to turn into reactive nitrogen.
Path 1: N2 > lightning> into soil> nitrate
Path 2: N2> Nitrogen fixation soil bacteria>decomposition>amino
Path 3: N3> Nitrogen fixation symbionts rhizobia in plants>plant is consumed by
animal>animal excretion into soil>uric acid & urea> ammonia>nitrite>nitrat
Now let’s see how nitrate turns back into unreactive nitrogen gas
Path 1: Nitrate>denitrifying bacteria>N2
Path 2: Nitrate> absorbed by plants>path 3 .
Remember, 78% of nitrogen gas!
There is not a lot of nitrate in soil because of competition.
Nitrate is a bio accessible form