January 7 ~Feb1 2013
Midterm date: Monday Febuary 4 2013. 5-7pm
Module 2: Begins on Tuesday Feb 5 . th
Total: 12 lectures
1-2: Tree of life-plants
3-4 Plant cells and plant tissues
5-6. From seed to tree
7-8. Freom tree to seed
9. Transport in plants
10. Plant nutrition and soils
11. Plant defense
12. Plant life on the edge.
Lecture 3 notes (Plant cells and plant tissues)
A) Undifferentiated cells: meristems
Plants have indeterminate growth because plants need meristem.
Limiting factors: soil nutrieds, bug, weather
Humans have determinate growth because they have stem cells.
Limiting factors: number of cells.
By dividing, meristematic cells give rise to more meristematic cells and specialized
& differntiated cells.
Primary meristematic cells: shoot apical meristem (SAM) and root apical
Secondary meristem: many different ones, different locations.
o Axillary meristem, Lateral meristem, Adventitous meristem, Vascular
cambium, cork cambium. Shoot apical mersitem
Leaf primordia protects shoot apical meristem.
From inside to outside: apical meristem>young leaves (leaf
primordia)>rudimentary leaf>latueral, auxillary bud.
Root apical meristem
3 sections from top to bottom: zone of cell differentiation>zone of cell
elongation> zone of cell division.
Apical meristem and root cap
B) Differentiated cells
Simple tissue: tissue made of one cell type
Complex tissue: tissue made of more than one cell type
i) Simple plant tissues
a) Parenchyma cells- most common cell types. Alive. Thin-walled, least specialized,
main functions: space filler in vascular bundles , photosynthesis (cholorenchyma –
parenchyma with chloroplast) , storage of water and nutrients in roots, leaves,
seeds, fruits (protein and starch).
b) Collenchyma: alive, elongated, thickened in cell corners.
Main functions: flexible storage in young stems, roots, petioles or around vascular
Typically located nearby vascular bundles.
c) Sclerenchyma- dead at maturity, cell interior almost completely filled.
Main functions: structural length.
Expeinsive to produce.
Two types: sclereids-often short cell,branched, in single or aggregated (e.g. hard
seed coats, shells of nuts, pear flesh) & fibers-flax plants (