lecture 10: Plant Physiology Flashcards
(40 cards)
1
Q
What are the two systems in plants
A
root system & shoot system
2
Q
describe the root system
A
- below ground
- absorption
- bringing water in
- stability
3
Q
describe the shoot system
A
- above ground
- stems, leaves, flowers, and fruit
- photosynthesis, reproductive structures
4
Q
what is the hierarchical orginization of plants
A
- cells
- tissues
- tissue system
- organs
- roots
- stems
- leaves
5
Q
describe roots
A
- underground in soil
- anchor to ground
6
Q
what are the functions of roots
A
- absorb minerals and water
- store carbs, sugar, starches, and other reserves, vegetables
7
Q
what are root hairs
A
- thin extensions of root epidermal cells
- where water enters ( osmosis)
- primarily near tip of elongated roots
8
Q
describe the stems
A
- plant organs bearing leaves and buds
- elongate and orient shoot to maximize photosynthesis
- elevate reproductive structures - increase pollen and seed dispersal
- photosynthesis, sometimes
9
Q
describe the leaves
A
- main photosynthetic organ in vascualr plants
- capture light, gas exchange ( wide surface area, thin so light can pentrate hit chloroplasts, spines in cacti are defensive)
- photosynthesis
- may help attract pollinators
10
Q
what is the dermal tissue system
A
- outer protective covering
- nonwoody plants ( epidermis, cuticle)
- wood plants ( periderm)
11
Q
epidermis
A
single layer of tightly packed cells ( green non-woody plant)
12
Q
cuticle
A
waxy coating- prevent water loss/ desiccation ( all land plants, not cells, layer of wax) -> protects against sun damage, herbavores)
13
Q
periderm
A
- (bark) replaces epidermis, all plant epidermis, only some plants bark,
14
Q
what are the functions of the dermal tissue
A
- defence, absorbtion
- reduce water loss, reflect sunlight, protect
- roots: absorption of water, minerals at root hairs
- leaves,stem: gaurd cells- specialized cells in shoots - gas exchange - open and close stomata, protection
15
Q
ground tissue system
A
- most of plant ( mesoderm of plant)
- anything not vascualr or dermal
- between outside and transport parts
16
Q
the ground tissue system included cells specialized for
A
- storage
- photosynthesis
- support
- short distance transport
-metabolism - ## storage
17
Q
Vascular tissue system
A
- transports materials throughout plant body
- long distance transport: water, sugar, hormones, minerals
- xylem cells: strong, structural support ( looks like straws)
18
Q
xylem
A
- conducts H20, dissolved minerals upwards from roots into atmosphere
- water and minerals: from roots -> sky
19
Q
phloem
A
- transport sugars from where made (mostly leaves) to where needed ( usually roots and sited of growth)
- sugar and hormones around plant
20
Q
water movement through xylem
A
- atmosphere
- stomata
- leaf mesophyll
- leaf xylem
- stem xylem
- root xylem
- root tissue
- soil
21
Q
cohesion-tension hypothesis
A
- during photosynthesis, stomata open H20 leaves
- sun rises -> photosynthesis + evaporation _> stomata open -> transpiration
- water is pulled upwards
22
Q
transpiration
A
- water leaving the plant, loss of water through evaopartion at the leaf surface
- negative pressure pulls water up
- passive process- No ATP involved
- plant can control this: opening and closing of stomata ( gaurd cells in epidermis regulate how fast water is moving)
23
Q
cohesion
A
H20 sticks with H bonds
24
Q
adhesion
A
H20 sticks to other things with H bonds (xylem is polar, water is polar)
25
describe cohesion tension
1. h20 in stem xylem pulled into leaves
2. h20 in root xylem pulled into stem
3. creates a void, area of low pressure
4. pulling, negative pressure
5. cohesion, pulling water molecules- high pressure -> low pressure (adhesion between water and plant)
26
Phloem conducts dissolved sugar
- bidirectional movement - translocation (mechanism)
- moves source (surplus) -> sink (net demand)
- not constabt, always move
- phloem eating enscets are devestiating to plant, increase pressure, rob plant of suagar
27
sink
area of storage or metabloism
28
source
area with excess sugar
29
pressure- flow - hypothesis
- explanation for movements of sugars in pholem
- suggests translocation occurs via pressure gradient
- at source - high pressure - sugar loaded into phloem
- at sink - low pressure - sugar removed from phloem
30
plasmodesmata
- cytoplasmic connections
- allows molecules, ions to pass between cells, without PM or cell wall
- important for plant transplant
- no energy costs across membrane
31
indeterminate growth
1. occurs throughout life of plant
2. due to perpetually dividing unspecialized tissue
3. depends on situation, not final form
4. grow only at apical meristems ( at the tip)
32
1 degree growth
- increase length by adding more cells ( result of growth at the meristem)
- all plants have 1 degree growth
33
seq 1 degree growth
- plants grow up and down from tips
- enlogation
- bike tree
34
2nd degree growth
- increases girth (circumference) of plant
- lateral meristems - vascular and growth tissue , gain width
- only woody plants have 2 degree growth
35
hormones
internal chemical signal
36
plant hormone
growth regulators, may have multiple effects, stress ( no water no sunlight
37
what are auxins
1st planthormone discovered - affects phototropism
38
what are tropisms
directional growht responce to environmental stimulus - often due to hormones `
39
what are the directions of tropisms
positive - growth towards stimulus ( leads grow towardss light)
negative - grows away from stimulus ( root grows away from light)
40
seq phototropism
1. light exposed - auxins produced
2. triggers enlogation
3. shade side enlogates -> plant bends towardss light
4. light side- not effected
