plant biology Flashcards
1
Q
indeterminate growth
A
grow forever
2
Q
determinate growth
A
predetermined growth
3
Q
adaptations to terrestrial environment
A
-waxy cuticle
-stomata
-vasculature
-pollen
-seeds
-support
-nutrient/water scavenging systems
-organ specialization
4
Q
sporopollenin
A
biopolymer that resists harsh environments
5
Q
challenges for land plants
A
-less buffered
-lack of structural support
-reproduction on land is hard
-water scarcity
-inaccessible nutrients in soil
6
Q
how to deal with lack of structural support?
A
-already had rigid cellulosic cell walls
-already had a hydrostatic skeleton
-holdfast vs. rhizoids and then roots
-eventually can even modify stems/leaves to make tendrils
7
Q
charophytes
A
green algae; closest relatives to land plants; contain sporopollenin
8
Q
anthocyanins
A
uv protective pigment
8
Q
hydrostatic skeleton
A
water pressure inside cells pushing against cellulose creating a “skeleton” to support vertical growth
9
Q
liginin
A
very tough polymer used by plants to structurally reinforce certain cell walls (ie wood)
10
Q
holdfast
A
a structure in algae that secures them to a particular spot
11
Q
rhizoids
A
simple root-like structures in nonvascular plants that anchor them to a substrate but do not transport water or nutrients like true roots
12
Q
key traits in plants that are absent in charophytes
A
-alternation of generations
-walled spores produced in sporangia
-multicellular gametangia
-multicellular, dependent embryos
-apical meristems
13
Q
bryophytes
A
-gametophyte dominant
-waxy cuticle and in some cases stomatal pores
-lack vascular systems and structural support
-no true leaves
-flagellated sperm require a film of water to most to an egg
-no roots, just rhizoids
14
Q
stomata
A
pores used for gas exchange
15
Q
seedless vascular plants
A
-sporophyte dominant
-vascular tissue (xylem and phloem)
-well-developed roots and leaves
-sperm are still water-dependent
16
Q
pollen grains
A
developed from the microspores; contain male gametophytes
17
Q
pollination
A
the transfer of pollen to the part of a seed plant containing the ovules
18
Q
evolutionary purpose for pollen
A
eliminates the need for a film of water; can be dispersed great distances by air or animals
19
Q
germination
A
the pollen grain gives rise to a pollen tube that discharges sperm into the female gametophyte within the ovule
20
Q
gymnosperm
A
cone-bearing plants; vascular seed plants that produce pollen and seeds in cones
21
Q
seed
A
embryo and nutrients surrounded by a protective coat; produced by gymnosperms and angiosperms
22
Q
angiosperm
A
flowering plants; vascular seed plants that produce flowers and fruit
23
Q
sepal
A
part of a flower derived from highly modified leaves that is external to the petals; form the protective outer layer of the flower bud, but usually do not serve much purpose in the opened flower
24
carpel
the entire female reproductive structure of a flower
25
stamen
the male reproductive structure of a flower; consist of an anther where pollen is made and a stalk called the filament
26
petal
part of a flower derived from highly modified leaves that usually serves to visually attract animal pollinators by displaying colors
27
ovary
the female structure at the base of the carpal in a flower that contains the ovules and, following pollination, matures into a fruit
28
ovule
sac-like structures inside a flower's ovary that hold the female gametophyte; following fertilization, they mature into seeds
29
anther
the meiotically-active part of the angiosperm stamen (male organ) that houses the microspores and eventually splits to release mature pollen
30
stigma
part of the carpal (female organ) of a flower; the wide tip at the end of the style which receives pollen and is the target site for pollination
31
style
part of the carpal (female organ) of a flower; a stalk extending up from the ovary and ending in a stigma; the organ that the pollen tube grows through to reach the ovules
32
receptacle
a swelling of the shoot at the base of a flower to which the flower parts are attached
33
pollen tube
the elongating cell of a pollen grain that contains the generative cell and grows down a flower's style towards the ovules; delivers the sperm to the egg cell
34
embryo sac
the female gametophyte of an angiosperm located inside an ovule consisting of eight haploid cells
35
integument
the layered sporophyte tissue forming the outside of the ovule; within it is the megaspore and then the embryo sac; will mature into the seed coat after fertilization
36
micropyle
an opening in the integument of an ovule through which a pollen tube can enter and fertilize the embryo sac inside
37
double fertilization
the fertilization process of angiosperms where two sperm cells are formed, one fertilizing the egg cell to form the zygote and the other fertilizing the polar nuclei to form the endosperm
38
endosperm
triploid tissue within the angiosperm seed that stores nutrients for the developing plant embryo
39
cotyledon
seed leaves; embryonic structures in a seed that may be the first leaf-like structures to emerge; often play a role in nutrient storage or transport for the developing embryo
40
monocots
have a single cotyledon, coleoptile, and other traits; includes grasses and other relatives
41
dicots
have two cotyledon and other traits; eudicots
42
radicle
the embryonic root that germinates and gives rise to the plant's root system
43
hypocotyl
embryonic shoot that emerges from a dicot seed; supports the cotyledons
44
coleoptile
hollow sheath-like structure found in monocots that emerges from the seed as the beginning of a shoot system, giving rise to the stem and first leaves
45
root functions
-anchoring the plant
-absorbing minerals and water
-storing carbohydrates
46
primary root
first root to emerge
47
lateral roots
grow laterally from the primary root; improve anchorage and water absorption; explore the soil
48
root hairs
small roots near the root tip which increase the surface area of the root
49
adapted root functions
-support
-storage
-air supply
-more
50
vegetative shoot
do not form flowers or reproduce; only there to perform photosynthesis and support the plant
51
primary growth
the development of new tissues in a plant through cell divisions that cause structures like roots and shoots to get longer and more branched
52
secondary growth
the development of new tissues in certain plants through cell division that cause roots and shoots to get wider and develop wood and bark
53
fibrous root system
a root system with manly finely divided roots and no main central taproot; usually the root system found in monocots
54
taproot
a root system with a large, usually thick primary root and many much smaller lateral roots branching from it; grows vertically down, deep into the soil; usually the root system found in dicots
55
stem
a stalk-like vascular part of the shoot system that supports leaves and flowers and can be modified for other functions; consists of nodes and internodes
56
nodes
the points at which leaves are attached; where vasculature comes together; may contain meristems
57
internodes
the stem segment between nodes
58
apical bud
growing shoot tip (apical meristem of the shoot); causes the elongation of a young shoot
59
axillary bud
(axillary meristem) structure that has the potential to form a lateral branch, thorn, or flower
60
axil
junction between the stem and leaf
61
petiole
leaf stalk by which the leaf connects to the stem
62
types of modified leaves
-spines
-tendrils
-reproductive (clone) leaves
-storage leaves (bulbs)
63
branching pattern of monocots
parallel veins
64
branching pattern of eudicots
branching veins
65
rhizome
an underground shoot that grows and branches horizontally, often helping a plant colonize an area
66
stolon/runner
an above-ground shoot that extends away from its parent plant, spreading horizontally over the ground with new plantlets growing along its length as an asexual reproductive strategy
67
tuber
an underground shoot that swells to form a storage organ; can also be used as a mean of asexual reproduction
68
trichome
hair-like structure on a plant's epidermis
69
dermal tissue
protective, external layer of cells that functions as the barrier between the inside of the plant and the environment outside of it
70
ground tissue
tissue that is neither vascular nor dermal; photosynthesis, structural support, storage, etc.
71
vascular tissue
tube-like, rigid cells that move water and dissolves solvents
72
cortex
ground tissue that is external to the vasculature
73
pith
ground tissue that is internal to the vasculature
74
parenchyma cells
-have thin and flexible walls
-are the least specialized
-retain the ability to divide and differentiate
75
collenchyma cells
-grouped in strands and help support young parts of the plant shoot
-have thicker and uneven cell walls
provide flexible support without restraining growth
76
sclerenchyma cells
-rigid because of thick walls strengthened by lignin
-dead at functional maturity
77
xylem
conducts water and dissolved minerals upward from the roots to the shoots (only upward); dead cell walls that form tubing; wood
78
phloem
transports sugars from where they are made to where they are needed (up, down and horizontally); living cells
79
types of xylem
vessels and tracheids
80
sieve-tube elements
alive at functional maturity but lack organelles (only membrane and cytoplasm); transports sugars through osmosis; have companion cells
81
sieve plates
porous end walls that allow fluid to flow between cells along the sieve tube; connects the cytoplasm of sieve-tube cells
82
companion cell
nucleus and ribosomes serve both itself and its sieve-tube element
83
stele
vascular tissue of a root or stem
84
stele of the roots in angiosperms
solid cylindrical center
85
stele of the stems and leaves in angiosperms
divided into vascular bundles
86
vascular bundles in dicot stems
grouped in a ring
87
vascular bundles in monocot stems
sporadic
88
root cap
protects the apical meristem as it pushes through the soil
89
zone of cell division
site of primary growth of a root; includes the apical meristem
90
zone of elongation
growth pushes root tip into soil; fueled by water pressure within cells
91
zone of differentiation
mature root cells begin functioning within their role
92
quiescent center
part of a root's apical meristem with inactive cell division to reduce the risk of mutations and take over the meristem's role in case it develops serious genetic error
93
pericycle
layer of cells in the root lining the outside of the vascular cylinder; where lateral roots emerge
94
leaf primordia
part of a shoot bud; the undeveloped tissues that divide to produce new leaves; found around the apical meristem
95
axillary meristem
the buds located within the axil that are usually inactive but have the potential to produce a lateral shoot through primary growth
96
lateral meristem
regions of continuous growth in root and shoot tissue that are no longer undergoing primary growth; responsible for secondary growth, the formation of wood and bark
97
vascular cambium
a tissue of the lateral meristem that produces new xylem and phloem in secondary growth, creating wood; connects vascular bundles using ground cells and turning them into meristem cells
98
cork cambium
a tissue of the lateral meristem that produces more epidermis in secondary growth, creating bark
99
secondary phloem
accumulates outside of the vascular cambium
100
secondary xylem
accumulates inside the vascular cambium
101
water potential
Ψs + Ψp
102
Ψp
-positive if pumped
-negative if sucked
103
Ψs
-negative
-gets more negative as solute levels rise
-Ψs is 0 in pure water
104
pressure and osmosis
-water always moves from more positive to more negative Ψ
-the more dissolved solutes, the more negative Ψs
-the more dissolved solutes, the more water wants to move into an area by osmosis
105
transpiration
the movement of water up the xylem and into the atmosphere, driven by the evaporation of water through the stomata
106
translocation
the directed movement of water and dissolved sugars through the phloem
107
how the stomata controls transpiration
-transpiration is controlled by the plant opening and closing its stomatal pores
-guard cells on either side of the pore regulates whether it is open or closed
-opening and closing is controlled by the turgor pressure within the guard cells
-guard cells turgid: stomata open
-guard cells flaccid: stomata closed
-potassium ions play a role in
stomatal opening and closing
108
abscisic acid
a plant hormone produced in response to drought and other stress that causes stomatal closure
109
apoplast
outside the plant cell; cell wall space and the inside of the dead xylem vessels
110
apoplastic route
a pathway water and dissolved solutes can take into the root system by moving through interconnected cell walls, as opposed to the cytoplasm
111
symplast
inside the plant cell; the cytoplasm through the plasma membrane
112
symplastic route
a pathway water and dissolved solutes can take into the root system by moving through the shared cytoplasm of adjacent cells via the plasmodesmata
113
plasmodesmata
pores in the plant cell walls that allow the cytoplasm and cell membranes of neighboring cells to be continuous and joined together so that molecules can easily pass between cells
114
endodermis
a ring of cells in the root between the cortex and vascular bundle (stele) that acts as a barrier for molecules entering the xylem from the cortex
115
casparian strip
a ring of waterproof waxy material that encircles the cell walls of a root's endodermis, thus blocking the apoplastic route
116
source
a part of a plant at a given time that has sugar to be exported to other parts of the plant, either because sugar is stored or produced there
117
sink
a part of a plant at a given time that requires sugar to be transported in, either because sugar is being accumulated or consumed there
118
sucrose-proton symporter
an active transport protein in sieve-tube cell membrane that co-transports sucrose into the cell against its concentration gradient and protons down their concentration gradient
119
uptake of mineral nutrients
-the endodermis regulates and transports needed minerals from the soil into the xylem
-water and minerals move from the protoplasts of endodermal cells into their own cell walls
-diffusion and active transport are involved in this movement from symplast to apoplast
-water and minerals now enter the xylem tracheids and vessel elements
120
chemiosmosis
powering something by coupling it to H+ movement across a membrane
121
bulk flow by positive pressure
in the sieve tube (phloem)
1) loading of sugar
2) uptake of water
3) unloading of sugar
4) recycling of water
122
9 essential macronutrients
-carbon
-oxygen
-hydrogen
-nitrogen
-phosphorus
-sulfur
-potassium
-calcium
-magnesium
123
8 essential micronutrients
-chlorine
-iron
-manganese
-boron
-zinc
-copper
-nickel
-molybdenum
124
rhizosphere
a sphere of influence in the soil created and maintained by a plant's roots that hosts a specific community of beneficial microbes
125
rhizobacteria
free-living, root-associated bacteria living in a plant's rhizosphere
126
endophyte
nonpathogenic bacteria that live between the cells of host plant tissues; mutualistic beneficial relationship
127
how endophytes and rhizobacteria help enhance plant growth
-produce chemicals that stimulate plant growth
-produce antibiotics that protect roots from disease
-absorb toxic metals or increase nutrient availability
128
root nodule
round, knobby swellings on the roots of legume plants that house nitrogen-fixing rhizobium bacteria
129
mycorrhizae
a type of mutualistic relationship between plants and certain root-associated fungi
-the plant provides the fungus with
carbohydrates manufactured
through photosynthesis
-fungus provides mineral nutrients
like nitrogen and phosphorus
-the fungus increases surface area
for water uptake and mineral
absorption
-the fungus secrete growth factors
that stimulate root growth and
branching
130
mesophyll
the ground tissue within a leaf that does most of a plant's photosynthesis
131
spongey mesophyll
the type of mesophyll between the palisade mesophyll and the lower epidermis which has cells packed less densely with many air spaces in between
132
palisade mesophyll
the type of mesophyll just under a leaf's upper epidermis which has rectangular and closely packed cells
133
coevolution
two types of organism both evolving traits over time that make them better participants in mutually beneficial behavior, often leading to an exclusive partnership
134
fruit
mature ovary of a flower; protects the enclosed seeds and aids in the dispersal by wind or animals
