Midterm 2 - How Plants Work Flashcards
1
Q
dormancy
A
- period of no growth and slow metabolic processes
2
Q
abscisic acid
A
- induces dormancy
3
Q
dormancy-breaking stimuli
A
- water
- warm temps
- light
4
Q
phytochrome
A
- plant pigment protein
- 2 reversible forms: Pr and Pfr
- mediates changes in response to light
4
Q
Pr, Pfr
A
- Pr: absorbs red light, becomes Pfr
- Pfr: absorbs far red light, becomes Pr
5
Q
auxin
A
- plant hormone
- influences cell elongation, gravitropsim, apical dominance, and root growth
6
Q
cytokinin
A
- plant hormone
- promotes cell division
7
Q
root-shoot balance
A
- too much of either is a disadvantage
- too much root: root bound, stunted growth, death
- too much shoot: can’t receive chemical signals
8
Q
suction
A
- draws water upward from roots to leaves
8
Q
capillarity
A
- movement of liquid through a narrow space
9
Q
root pressure
A
- helps drive fluid upward from soil into water-conducting xylem vessels
10
Q
water potential
A
- potential energy of a water solution per unit volume
11
Q
pressure potential
A
- positive or negative
- higher pressure = greater potential energy
12
Q
solute potential
A
- osmotic potential
- negative in plant cell, 0 in distilled water
13
Q
matric potential
A
- amount of water bound to the matrix or a plant via hydrogen bonds
- negative to 0
14
Q
gravity potential
A
- negative or 0
- in a plant with no height
- no height = no potential energy
15
Q
water potential gradient
A
- continuous movement of water relies on it
16
Q
cohesion-tension theory
A
- as water moves up the plant, it moves down a water potential gradient
17
Q
stomata
A
- tiny openings on epidermis of leaves
- gaseous exchange
- photsynthesis
18
Q
cell wall bands
A
- central to growth
- strong but extensible wall
19
Q
high turgour
A
- optimal form
- plant body in favourable position
20
Q
low turgour
A
- causes cell to shrink inwards
21
Q
pressure flow model of phloem transport
A
- high concentration of sugar at the source creates a low solute potential
- low potential draws water into phloem
22
Q
source
A
- where sugars are
- roots, stems
22
Q
sink
A
- where sugars end up
- require photosynthate
- roots and young leaves
23
Q
resource partitioning
A
- division of limited resources
24
Q
tropism
A
- growth toward or away from stimulus
- adaption to environmental changes
25
Q
positive phototropism
A
- bending towards light
25
Q
phototropin
A
- blue-light receptor
- promotes phototropism, stomatal opening and closing, and other responses that promote photosynthesis
26
Q
IAA
A
- naturally occurring plant hormone of the auxin class
27
Q
expansins
A
- cell wall proteins
- mediate acid-induced growth
27
Q
positive gravitropism
A
- growth toward earth’s gravitational center
28
Q
negative gravitropism
A
- growth away from earth’s gravity
29
Q
thigmotropism
A
- directional growth of a plant in response to direct contact
30
Q
photoperiod
A
- regulation of physiology or development in response to day length
31
Q
short-day plants
A
- need long period of darkness to form flowers
32
Q
long-day plants
A
- only flowers when light period is longer than a critical length
33
Q
day-neutral plants
A
- don’t follow restriction of critical duration
- neutral to length of day or night
34
Q
ethylene
A
- volatile plant hormone
- associated with fruit ripening, flower wilting, and leaf fall
35
Q
senescence
A
- natural process of aging
36
Q
abscission
A
- physiological process
- leads to fall of a plant organ
