PLANTS

What's in a name? That which we call a rose
By any other name would smell as sweet.
--William Shakespeare, Romeo and Juliet

on this outline:
Plant structure and growth Campbell and Reece Chapter 35
Transport in plants Campbell and Reece Chap 36
Plant nutrition Campbell and Reece Chap 37
Integrative systems in plants Campbell and Reece Chapter 39

(plant reproduction, chapter 38, is in a separate outline)

Tree trunk TRANSPARENCY Fig. 35.23 - (***see also below) heartwood (old secondary xylem - resins clog)
and sapwood (functional secondary xylem, vascular cambium,
young secondary phloem and cork cambium)
annual growth rings - spring wood and summer wood
(stem TRANSPARENCY Fig. 35.21)
this is secondary xylem

TRANSPARENCY (Fig 35.13) winter twig shows primary growth for contrast

Annual, biennial, perennial

Flowering plants (angiosperms) monocots and dicots TRANSPARENCY Fig. 35.1 (+++see also below)

monocot, parallel veins, complex vascular bundles (in stems vs roots), fibrous roots, 3x flowers (corn)
dicot, net veins, vascular bundles in ring (in stem vs root), tap root, 4x or 5x flowers (bean)

Cell growth by size mostly of vacuole TRANSPARENCIES 7.8, 7.15 review
Development is continuous in plants - meristems
TRANSPARENCY Fig. 35.12 in book Meristems: Shoot apical, lateral and root
plant growth - indeterminant - meristems
stem node, internode, bud, terminal bud TRANSPARENCY Fig. 35.2
apical meristems - primary growth
also from apical meristem of roots TRANSPARENCY Fig. 35.14
lateral meristems - secondary
TRANSPARENCY Fig. 35.21 in book Anatomy of a woody dicot stem
not in most monocots, amazingly not in palm TRANSPARENCY Figure from another book.
Compare with TRANSPARENCY Fig. 35.18b in book monocot young stem
lateral meristem is vascular cambium recall (*** see also above) (again) TRANSPARENCY Fig. 35.23
makes vascular tissues, xylem and phloem
later become
bark - cork cambium and cells it makes

Plant cells and tissues
Review leaf TRANSPARENCIES 7.18, 10.2, 35.19
Parenchyma cell, generic TRANSPARENCY Fig. 35.11
stem, root plastids with starch
flesh of fruit
Collenchyma - support
Sclerenchyma - strong support (cell walls so important in plants)
Vascular
review cell structure - cell wall, vacuole TRANSPARENCY 7.28, 5.8
Xylem - water transport (root, stem, leaf)
tracheids long thin, strong, connect at tapered ends
TRANSPARENCY Fig. 30.12 and 35.8
and vessel elements (evolved later) end to end
at maturity - empty (no protoplasm) cell wall
connected by pits with, e.g., plasmodesmata
TRANSPARENCY (Fig. 35.9) phloem's sieve-tube members and companion cells

Water transport

Thanks to the comment from a perceptive student, I fixed incorrect wording here between the 1/17 and 1/31 versions of this outline:

Osmosis - water moves passively from where water is at a higher concentration (for instance pure water) to where water is at a lower concentration (where organic chemicals are dissolved in it) through a semipermeable membrane (i.e. a membrane which passes water but not the organic molecules).

In root: water is extracellular to endodermis where Casparian strip makes barrier (TRANSPARENCY Fig. 36.7) which forces water to move to intracellular
Minerals (like K+) by active transport (ATP and H+ pump)
very little "push" from roots Guttation
pump can lift water 34 feet, atmospheric pressure pushes
TRANSPARENCY Fig. 36.1 (in general, water goes up and sugar goes down, simple)
TRANSPARENCY Fig. 36.11 water adhesion (to xylem), cohesion, capillary action
pulled by transpiration
transpiration up to 97% of water use
Adaptations for avoiding water loss
C4 photosynthesis
CAM (crassulacean acid metabolism) take in CO2 at night
TRANSPARENCY (stomata Fig. 36.13, leaf Fig. 36.10)
corn 2 liters per day
maple tree 200 l / hr in summer
help to cool

Phloem - sugar transport - sieve tubes and companion cells
from leaves (source) to roots (sink)
seasonal sap flow

Recall TRANSPARENCY (again) Fig. 35.1 (+++see also above) variations
big vascular bundles, phloem outside in radial array:
dicot
small vascular bundles throughout monocot

Roots - taproot in dicot, fibrous in monocot
very branchy - 1 rye grass 4000 sq ft - root hairs extensive)
Osmosis
Root - epidermis & hairs
cortex (water around cell walls)
endodermis (casparian strip makes water thru cell)
regulate minerals
pericycle (root hair and secondary dev)
vascular bundles as one steele (vs in bundles in branch)
TRANSPARENCY Figs. 35.15
Mycorrhizae- fungus help nutrient uptake
see also TRANSPARENCY Figure from another book (like Fig. 36.8) that shows amazing extent
also root nodules (for nitrogen fixation, I'll show a slide later)
Unusual stems (TRANSPARENCY Fig. 35.64)-
stolon (strawberry)
rhizomes- iris, fern
tubers- potatoes - swelling in rhizome, Jerusalem artichoke
bulb - onion (modified leaves)
Parasitic plants like mistletoe tap into oak
vs. epiphytes like staghorn fern just use plant as substrate

Roots into "soil" - clay, sand, humus
problems of water retention and loss and compaction (aeration)
"no - till" agriculture
erosion
all nutrients except CO2
CO2 into carbohydrate, H2O split and only H2 into Carbohydrate
Chap 10 - carbon fixation - Calvin cycle
light reactions of photosynthesis split water

5 - 10 - 5 or 12 - 12 - 12
Nitrogen (guano), phosphorus (phosphate), potassium (potash)
NO3- nitrate, NH4+ ammonium, H2PO4- phosphate
root nodules of Rhizobium TRANSPARENCIES 37.9, 37.11
See root nodules on clover
also others, remember plants are "primary producers"
Be sure to look at table 37.1
Macronutrients
Magnesium in chlorophyll (epsom salt, magamp)
Sulfur in amino acids
Micronutrients
Iron in cytochromes (chelated iron)
Chlorosis if missing several nutrients, iron poor soil for evergreens
miracid

Integrative systems in plants Campbell and Reece Chapter 39

"motor" movements - fast, action potentials
fast movements-turgor changes-Mimosa Fig. 39.27
also Venus fly trap (Fig. 37.16)
also not so fast, introduce "tropism"
also "sensory"
statoliths in cells Fig. 39.25
geotropism (gravitropism) Fig. 39.25

TRANSPARENCY (Fig. 39.2) shows general hormonal mechanism
TRANSPARENCY Table 39.1 hormones
TRANSPARENCY (Fig. 39.17) growth mediated by blue light, cryptochromes and others
Auxins indole (3 acetic acid)
phototropism - Darwin expts.communication with tip for grass to grow to light
TRANSPARENCY Fig. 39.4 the early experiments
Went 1927 agar expts TRANSPARENCY Fig. 39.5
make cells grow more
apical dominance (pinch back flowers)
polar transport (active) from apical meristem of terminal bud
rooting hormones
weed-be -gone, ortho, scotts plus 2, 2,4-D; 2,4,5-T dioxin weed and feed
monocots resist, works on dicots, broad leafed
deadly agent orange

Ethylene - ripen fruit - kerosene heaters, blueberies, fruit rots
dropping of leaves in deciduous perennials
TRANSPARENCY (Fig. 39.15) quite a bit of work including isolation of ethylene mutants
Cytokinins - contain adenine coconut milk- cell division
Miller expts on aged herring sperm - degraded DNA
interact with auxin in callus vs. root
" " " in apical dominance
Gibberellins - cell elongation - dwarf corn and peas lack
foolish [rice] seedling disease fungus
flower earlier, better Thompson seedless grapes
barley (cereal) seed germination - break dormancy
mRNA for a-amylase act through 2nd messenger
involved in "bolting" with huge internode
Abscisic acid - inhibit growth prepare for winter
rain washes out of desert seed thus germinate
Phytochrome - photodormant lettuce seeds germinate after 660,
not 730 - also photomorphogenesis
photoperiodism - dark period important
Pr->Pfr
daylight hits red, slow reconversion TRANSPARENCY Fig. 39.20
TRANSPARENCY (Fig. 39.22) short-day (long night) plants and long day (short night) plants
TRANSPARENCY Fig. 39.23 red and far red in flowering
TRANSPARENCY (Fig. 39.3) mechanism involves signal transduction (see chapter 11)
Florigen - timing of flowers in short and long day plants

SLIDES (and hyperlinks) to review major points:
SLIDE root nodules of Rhizobium See root nodules on clover
SLIDE - mum - pinch off buds (that inhibit branching by apical dominance) early and the plant gets fuller
SLIDE sunflower usually has flower at top, but here, the top got broken off in a wind storm and the flower is on a side branch

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this page was last updated 1/31/03