Plant Physiology Flashcards
1
Q
systems
A
roots: below ground; shoot: above ground (stem, leaves,flower)
2
Q
cells
A
basic functional unit
3
Q
tissues
A
group of line cells, cummulative function
4
Q
3 tissue systems
A
dermal, vascular, ground
5
Q
organs
A
all 3 tissue system; stems, roots, leaves, flowers, fruits
6
Q
root system functions
A
anchors to ground; absoption of material taken up through roots; storage of carbs produced and stored here
7
Q
root system structures
A
primary root; lateral roots; root hairs
8
Q
primary root
A
originates in seed embryo
9
Q
lateral roots
A
grow and branch off of primary root
10
Q
root hairs
A
thin finger like extensions of root epidermal cells; increases SA, increases absorption, increases mineral nutr. uptake; near tips of elongating roots; old roots don’t have hair
11
Q
epidermal cells
A
outer covering
12
Q
shoot system
A
steam, leaves, flower
13
Q
stem organ functions
A
bear leaves and buds; elongate/orient shoot to maximize light uptake for photosyn by leves; eleveates repro structure, pollen and fruit doesn’t devevlop on ground bc stem makes them grow higher up and aids in dispersal; photosyn in stem sometimes must have green stem
14
Q
stem organ structures
A
nodes, axilary buds, internodes, apical bud
15
Q
nodes
A
point hwere leaves are attached
16
Q
axilary buds
A
form lateral branches; lots of things grow outwards, more light, more photosyn
17
Q
internodes
A
stem structures btwn nodes
18
Q
apical bud
A
growing shoot tip; lots of young shoots develop here
19
Q
leaves organ functions
A
main photosyn organ in most vascular plants; capture light; gas extange site
20
Q
leaves organ structures
A
blade, petiole stalk, veins
21
Q
blade
A
flattened part of leaf
22
Q
petiole stalk
A
joins leaf to stem @ node; not in all plants (ex: many grasses w/o petiole)
23
Q
veins
A
vascular tissue for conduction and support; patterns btwn monocots and dicots
24
Q
vein pattern in monocots
A
parallel major veins w same diameter as leaf
25
vein pattern in eudicots
branched network arises from midrib down middle of leaf
26
dermal tissue system
outer protective covering of org to defend against pathogens and physical damage
27
dermal ts in non woody plants
epidermis = single layer of tightly packed cells; cuticle that covers epidermis and prevents water loss (waxy covering)
28
dermal ts in woody plants
epidermis replaced by periderm in older regions of stem and root
29
function of dermal ts
absorption at root hairs; guard cells; some plants w characteristic trichomes, relect excess sunlight found in desert spp to decrease H2O loss, insect defense
30
trichomes
specialized epidermal cells in shoots
31
ground tissue system
majority of plant composition; variety of cells w variet of functions: storage, support, photosyn, short distance transport; 2 types: pith, cortex
32
pith
ground ts, internal vascular tissue w/i stele
33
cortex
ground ts, external to overall vascualr sys
34
vascular ts functions
transport materials/move through plant body; support to prevent falling cover
35
2 main types of vt
xylem and phloem
36
xylem
conducts water and disscolved material upwards; absportion of H2O in roots conduction to shoots
37
phloem
conducts sugar made in leaves througout body (dissolved sugars); bi-directional; sugar made in leaves dwn to roots for use/storge (active transport); sugar stored in roots moved up to other parts for growth/maintenance
38
stele
all vas tissue of root/stem; var in arrangement depending on spp
39
root stele in angiosperms
solid central cylinder w X and P
40
stem/leaf stele in angiosperms
vasucalr bundles w/ X and P
41
success of plants
ability to gather resources from their env and transport materials to where they are needed
42
vascular plant adaptions
acquistion of H2O, minerals, light, CO2; transport of H2O, minerals, sugars
43
key to plant success
balancing tradeoff btwn maximizing photosyn and minimizing H2O loss
44
long distance transport of H2O/minerals (bulk flow)
movement of liquid in response to pressure gradient indep. of concentration gradient; occurs w/i tracheid and vessel elements (xylem) and sieve tube elements (phloem); much faster than diffusion or active transport; 3 mechanisms of bulk flow: transpiration, cohension tension hyp, stomata opening/closing
45
transpiration
lose water vapor through leaves and other aerial parts so must be replaced by water transported up from roots; transports H2O/min. from roots to shoots via xylem; in xylem use bulk flow to transport H2O/min. through vein of leaves via H2O loss in transpiration
46
flow of transpiration
unidirectional movement of H2O: H2O/min from soil, root epidermis (root tissue), root cortex (root xylem), (vascular cylinder, xylem) stem xylem, leaf xylem, leaf mesophyll, stomata, atmosphere
47
cohension tension hyp.
bulk flow of H2O/min.; transpiration creates tension and causes H2O cohesion to pull H2O froom roots to shoots
48
transpiraton steps
leaf cells lose H2O; creates tension; H20from stem xylem moves to leaves; H20 from roots xylem moves to stem xylem
49
cohesion/adhesion
transpirational pull can extend down to roots only via unbroken chain H2O molecules
50
cohesion
H2O sticks to itself via H bonding and form unbroken columns
51
adhesion
H2O sticks to cellulose in xylem cel walls due to H bonding and adheres to wall of all xylem cells
52
mesophyll
ground tissue; upper layer w columnar cells for photosyn; lower layer w loosly arranged cells for gas extange
53
epidermis
dermal tissue; upper and lower structues covered by cuticle to reduce H2O loss
54
stomata
dermal tissue; control gas extange; open in day for photosyn; closed at night/drought
55
stomata opening and closing
bulk flow of H2O/min.; each stomata w pair of guard cell to change shape due to H2O movement; into GC: tugid, bends to open pore; out of GC: flacid, collapses to close pore; 98% H2O loss through stomata
56
stomata opening/closing mechanism
blue light tiggers H+ pumps in GC membrance; pumps H+ out of cell; gradient drives facilliated diffusion of K+ into GC; Cl- other neg ions follow; [solute] higher inside GC; H2O moves into GC via osmosis; GC = tugid bends; changes shape; pore opens; H2O loss; transpiration/cohesion
57
photosyn
produces sugar; converted o glucose
58
phloem sap
acqueous solu high in surose, AAs, hormones, minerals
59
translocation
"food transport"; sugar source to sugar sink
60
sugar source
area w excess sugar (ex: leaf), sugar in loaded into phloem, high PG
61
sugar sink
area of storage/metabolism (ex: roots, seeds); sugar is unloaded from phloem, low PG
62
pressue flow hyp.
translocation of dissolved sugar in phloem occurs via pressure gradient; PG btwn source and sink
63
pressure flow mechanism in source
leaf: sucrose via photosyn moves into companion cells, active transport loads sucrose into seed tube element of phloem; STE: [solute] increases (hypertonic to xylem), H20 into STP from xylem via osmosis creates high pressure and pushes sugar sol. to lower pressure
64
pressure flow mechanism in sink
unloading; sugar move out STE into sink cell via active transport; pressure in STE increases (less neg.), STE now hypotonic to xylem, H2O moves out of STE to xylem via osmosis; STE back to "normal" ready to be reloaded
65
plant growth
characterized by intermediate growth (growth throughout plant's life, usually continuous unless dormant)
66
meristems
composed of cells that form new cells via mitosis
67
primary growth
activity of apical meristems at tips of roots and shoots; increase in stem/root length, roots=extend, stem=taller; all plants
68
secondary growth
in lateral meristems: vascular combium, cork cambium (increases girth); produces wood and bark of plant; in gymno & woody angio
69
vascular combium
adds layers of secondary xylem (wood) and phloem; secondary growth
70
cok cambium
replaces epidermis w periderm (much thicker); secondary growth
71
plant hormones
organic ompounds, chem messengers; general characteristics: active @ very [low], multi effects, interact w each other; control specific physiological responses; regulate plant growth; natural and synthetic
72
tropisms
directional plant grwoth response; produced by env stimulus; ex:phototrophisms; pos/neg
73
positive tropism
grows toward stimulus
74
neg. tropism
grows away from stimulus
75
auxins
first pant hormones to be disocvered; Darwin & son; phototropism exp
76
coleoptile
1st part of grass to emerge from soil, bends toward light; exposed to light from only 1 direction @ tip; discovery of auxin by Darwin and son
77
characteristics of auxin
natural & artifical; indoleacetic acid; main function = cell elongation @ shoots and cell wall (primary and secondary)
78
indoleacetic acid
IAA; most common/important plant auxin; mainly produced @ shoot apical meristem; moves unidirectionally down shoot via active transport
79
primary cell wall
cellulose fibers can be changed
80
second cell wall
cellulose and lignin; unable to expand
81
acid growth hyp.
auxin mechanism; auxin activity increases activity of H pumps; creates a low pH; activates expansins; seperate cellulose microfibrils from cross-linking polysacs; more expose/loosened CW; enx can cleave cross-linking polysacs; cellulose microfibrils slide; water enter via osmosis (tugor pressure); cell expands
82
phototropism
auxins; plant exposed to light; light = stimulus; auxin produced at tip; auxin travels laterally to shaded sides and moves down stem via polar transport
83
herbicides
cause auxin hormonal over does; death; kill plants w broad leaves
84
fruit development
developing seed + auxin = fruit growth; spray syn auxin on greenhouse tomatoes to get greater fruit dev from seeds
85
cytokinins
hormonal control of cell division; produced in actively growing tissues (roots, embryo, fruits); acts w auxin; anti-aging effects (mobilize nutr.)
86
parenchyma cells w/o cytokinin
grow large bc of auxin bu don't divide bc no cytokinin
87
parenchyma cell w cytokinin
grow large (auxin) and divide (cytokinin)
88
hormonal control of apical dominance
direct inhibition hypo: auxin at AM inhibits axillary bud growth; vs. cytokinins at roots to shoot promotes axillary bud growth, remove apical bud, no auxin and bigger plant
89
abscisic acid (ABA)
seed dormancy; seed only grows under suitable conditions; seeds have increased level of ABA but don't germinate until ABA washed out; drought tolerance
90
ABA drought tolerance
plant wilts; ABA accumulates in leaves; massive loss of K+ from guard cells; GC = flaccid; stomata closed; reduces transpiration
91
ethylene gas
triple response to mechanical stress; senescence; fruit ripening
92
triple response to mechanical stress
ethylene gas; maneuver to avoid physical obstacle; stimulus = physical obstacle; produces etylene; triple response: (1) slowing stem elongation (2) stem thickening = stronger (3) produce curvature = stem grows horizontally; once avoided, less ethylene and normal vertical growth
93
senescence
ethylene gas; programmed cell death of certain cell or organs or whole plant; via apoptosis (enz will break down everything): leaf shedding, death of annuals, vessel elem. dead @ maturity
94
fruit ripening
ethylene gas; @ middle lamella btwn CWs adjacent cells; pectin dissolves = soft fruit; color changes; starches/acids make sugar to make fruit sweet; chain rxn: ethylene triggers fruit ripening & fruite ripening triggers ethylene production; commerical tomato ripening on command
