Chapter 1: Vascular Plant Structure and Growth Flashcards
1
Q
These roots emerge from a variety of non-root locations, and for different reasons. Unlike the classic, “stem goes up, roots go down” type of growth, these roots appear at leaf and stem nodes, and at wound sites. What are they called?
A
Adventitious roots
2
Q
Why would a normal bud or shoot change its purpose and become an adventitious root?
A
Due to low oxygen levels (flooding, burial) or high levels of pollution.
3
Q
_______ are are adventitious roots that form from stem tissue. The main function of _______ is to provide structural stability for the stem.
A
Prop roots
4
Q
True or false: Roots are photosynthetic
A
False, they survive on photosynthates (sugars and carbs) imported from the shoot system.
5
Q
Tall, erect plants with large shoot masses generally have:
A
A taproot system - one main vertical root which develops from the primary root
6
Q
In taproot systems, which part is responsible for absorption?
A
The tips of the lateral rotos
7
Q
What do smaller vascular plants with less growth have instead of a taproot system?
A
A fibrous root system
8
Q
What happens to the primary root in plants with fibrous root systems?
A
It dies early on and does not form a taproot
9
Q
True or false: Most monocots have fibrous root systems, and most dicots have taproot systems
A
True
10
Q
What grows instead of a taproot in a plant with a fibrous root system?
A
Many small roots emerge from the stem, known as adventitious roots (e.g. roots arising from stems or leaves). Each adventitious root forms its own lateral roots, and they form their own lateral roots, and so on.
11
Q
Why do root systems form symbiotic interactions with soil fungi?
A
Mycorrhizal associations increase the plant’s ability to absorb minerals.
12
Q
Node
A
Point at which a leaf is attached
13
Q
Internodes
A
Stem segments between nodes
14
Q
The growth of a young shoot is concentrated near the _____ ____
A
Apical bud (growing shoot tip)
15
Q
The axillary bud can either form a
A
lateral branch, thorn, or flower
16
Q
A leaf consists of a flattened _____, and a stalk that attaches the leaf blade to the stem, known as the ______
A
blade; petiole
17
Q
A petiole joins the _____ to the ______ at a ______
A
leaf; stem; node
18
Q
X is a major leaf vein that runs down the center of the blade. It does not exist in most monocots and is common in dicot leaves, which tend to have a thick X.
A
Midrib
19
Q
Apical buds are also known as
A
terminal buds
20
Q
Carrots, beetroots, and potatoes are examples of
A
Taproots
21
Q
Leaf anatomy: _____ is a very thin hydrophobic layer that reduces water loss via transpiration. It’s why water droplets “bead” on a leaf
A
Waxy cuticle
22
Q
What are the two major clades of angiosperms?
A
Monocots and Dicots
23
Q
_____ are narrow-leaved plants
_____ are broad-leaved plants
A
Monocots
Dicots
24
Q
They are the plant equivalent of baby teeth. The first leaves are functional, but are intended to provide food to the plant early on until it develops enough to grow its own proper leaves.
A
Cotyledon
25
Which one has 1 cotyledon?
Monocot
26
Which one has 2 cotyledon?
Dicot
27
Which angiosperm clade has fibrous roots?
Monocots
28
Which angiosperm clade has tap roots?
Dicots
29
Most _______ have parallel major veins of equal diameter that run the length of the blade.
monocots
30
_______ generally have a branched network of veins
| arising from a major vein (the midrib) that runs down the center of the blade
Eudicots
31
In monocot flowers, the number of petals is
3 or a multiple of 3
32
In dicot flowers, the number of petals is
4 or 5 or a multiple of 4 or 5
33
Monocot stems have ______ vascular bundles.
scattered
34
Dicot stems have their vascular bundles in a _____ arrangement.
ringed
35
Each ______ is composed of a node, an internode, a leaf comprising sheath and blade or lamina, and an axillary tillering bud. They are the functional units of a plant.
Phytomer
36
______ are leaves that are highly specialized for sexual reproduction, such as carpels and stamens in flowers
sporophylls
37
What are the three three fundamental tissue types of the vascular plant organs (roots, stems, and leaves)?
1. dermal
2. vascular
3. ground tissues.
38
_______ are specialized storage stems of certain seed plants. _______ are usually short and thickened and typically grow below the soil. Largely composed of starch-storing parenchyma tissue, they constitute the resting stage of various plants and enable overwintering in many species.
Tubers
39
Popular example of a tuber
Potato
40
A horizontal shoot (plant stem together with its appendages, leaves and lateral buds, flowering stems, and flower buds) that grows just below the surface.....
Rhizome
41
horizontal shoots that grow along the surface. These “runners” enable a plant to reproduce asexually, as plantlets grow from axillary buds along each runner. _____ give rise to roots and aerial (vertical) branches at specialized points called nodes.
Stolons
42
Y serves as the outer protective covering of the plant. Like our skin, it forms the first line of defense against physical damage and pathogens.
Dermal tissue
43
_____ are an example of modified leaves
Spines
44
In nonwoody plants, the dermis is usually a single tissue called the _______, a layer of tightly packed
cells.
Epidermis (epi means upon)
45
What is the waxy epidermal coating that helps prevent water loss in leaves and most stems?
The waxy cuticle
46
The epidermis is the outer layer of leaves, young stems, and young leaves, whereas the _______ is the outer layer of roots and stems that have undergone secondary growth.
periderm
47
Very thin hydrophobic layer that reduces water loss via transpiration
Waxy cuticle
48
Tightly packed cells which prevent water loss. They are translucent in order to allow light to pass through for photosynthesis.
Upper epidermis
49
The palisade mesophyll is also known as the
palisade parenchyma
50
tightly packed column-shaped cells which can be 1, 2, or 3 layers thick and contain MANY chloroplasts.
Palisade mesophyll
51
The spongy mesophyll is also known as the
spongy parenchyma
52
irregularly shaped, loosely packed cells that contain some chloroplasts for some photosynthesis. Their intercellular spaces allow for gas exchange in and out of the leaf.
Spongy mesophyll
53
Guard cells are an example of specialized what?
Specialized epidermal cells.
54
In roots, water and minerals absorbed from the soil through which layer?
Epidermis
55
What do guard cells do?
```
What are guard cells? A pair of guard
cells surrounds each stoma on the
leaf surface. Stomata are important
because they regulate the uptake of
CO2 from the atmosphere for
photosynthesis and also the loss of
water vapour from the plant during
transpiration. The opening of the
stomatal pore is controlled by the two
guard cells. When the guard cells are
fully turgid the pore gapes open,
whereas when they lose turgor the
pore closes. Guard cells optimise leaf
gas exchange in response to changing
environmental conditions and their
turgor is controlled by alterations in
atmospheric CO2 concentration, light
intensity, humidity and the drought
hormone abscisic acid.
```
56
Vascular tubules within the plant which transport water from root to shoot (upwards flow).
____ conducts water and dissolved minerals
upward from roots into the shoots.
Xylem
57
What transports sugars, the products of photosynthesis, from where they are made (usually the leaves) to where they are needed or stored—
usually roots and sites of growth, such as developing leaves and fruits.
Phloem
58
The vascular tissue of a root or stem is collectively called
| the
Stele
59
How is the root stele arranged in angiosperms?
A solid central vascular cylinder of xylem and phloem,
60
How are the stem and leaf steles arranged in angiosperms?
Several vascular bundles, separate strands containing
| xylem and phloem
61
Tissue that is neither dermal nor vascular is
Ground tissue
62
Ground tissue that is internal to the vascular tissue is
| known as
Pith
63
ground tissue that is external to the vascular
| tissue is called
Cortex
64
What tissue type contains cells specialized for functions such as storage, photosynthesis, support, and short-distance transport.
Ground tissue
65
In a plant, as in any multicellular organism, cells undergo......
cell differentiation and become specialized in structure and function
66
What are the most abundant cell type that are found in all plant parts?
Parenchyma
67
Which differentiated cells are the only photosynthetic cells?
Parenchyma
68
Which differentiated cells are the only cells that engage in mitotic divisions?
Parenchyma
69
Which mature differentiated cells have primary walls that are relatively thin and flexible, and lack secondary walls?
Parenchyma
70
Which cells perform most of the metabolic functions of the plant, synthesizing and storing various
organic products?
Parenchyma
71
photosynthesis occurs within the chloroplasts of which
| cells in the leaf?
parenchyma
72
True or false: It is even possible to grow an entire plant from a single parenchyma cell.
True. Most parenchyma cells retain the ability to divide and differentiate into other types of plant cells under particular conditions—during wound repair, for example.
73
Which differentiated cells are elongated cells with irregularly thick cell walls that provide support and structure.
Collenchyma cells
74
Which cells help support the plant shoot?
Collenchyma
75
Which cells' thick cell walls are composed of the compound's cellulose (stiff and rigid) and pectin (stabiliser, thickening fiber?
Collenchyma
76
Which cells are often found under the epidermis, or in the outer layer of cells in young stems and in leaf veins?
Collenchyma
77
True or false: Collenchyma cells restrain growth but provide flexible support.
False. They do not restrain growth.
78
Which cells elongate with the stems and leaves they support?
Collenchyma
79
Which cells don't elongate with the stems and leaves they support?
Sclerenchyma
80
Which cells also provide support functions (like collenchyma cells) but are much more rigid than collenchyma cells?
Sclerenchyma cells
81
What makes sclerenchyma cells special?
They have thickened secondary cell walls that are thick and stiffened with large amounts of lignin (indigestible strengthening polymer- present in dry mass of wood)
82
Which mature cells cannot elongate?
Sclerenchyma cells
83
______ cells are so specialized
| for support that many are dead (commit apoptosis) at functional maturity, i.e. once the secondary cell wall is laid down
Sclerenchyma cells
84
What are the two types of Sclerenchyma cells and what are their functions?
1. Fibers: elongated cells that provide rigid support and are often in bundles. They are long, slender, and tapered.
2. Sclereids: boxier than fibers and irregular in shape,
have very thick, lignified secondary walls. May be densely packed like in nut shells, or in clumps as in stone cells in pears.
85
What happens after the sclerenchyma protoplast dies and the secondary wall is laid down?
The rigid walls remain as a “skeleton”
| that supports the plant, in some cases for hundreds of years.
86
What are the two types of water-conducting cells?
Tracheids and vessel elements - both TUBULAR, both ELONGATED, both DEAD at functional maturity (APOPTOSIS)
87
the living cellular contents of a tracheid or vessel element disintegrate, the cell’s thickened walls remain behind, forming a nonliving conduit through which water can flow. The secondary walls of tracheids and vessel elements are often interrupted by ____, thinner regions where only primary walls are present. Water can migrate laterally between neighboring cells
through_____.
pits
88
Tracheids have tapered ends
yeah, they also are long, thin cells
89
Why does water move from cell to cell mainly through the pits?
it does not have to cross the thick secondary walls of the tracheids and vessel elements
90
Vessel elements are generally 1.____, 2. _____, 3._____-____, and 4.____ _____ than the tracheids.
wider, shorter, thinner walled, less tapered
91
How are tracheids and vessel elements hardened and prevented from collapsing under the tension of water transport?
Their secondary walls are hardened with lignin
92
Are the sugar conducting cells of the phloem dead at functional maturity?
No. They're alive and well.
93
What are the long, narrow cells that sugars and organic molecules are transported through (IN GYMNOSPERMS)?
Sieve cells
94
In the phloem of angiosperms, these nutrients
| are transported through what?
Sieve tube elements
95
What do sieve tube elements lack? Why is this?
A nucleus, ribosomes, a distinct vacuole, and cytoskeletal elements
The reduction in cell contents allows for easier passage of nutrients through the cell
96
The end walls between sieve-tube elements, called ______ _______, have pores that facilitate the flow of fluid from cell to cell along the sieve tube.
sieve plates
97
What is alongside each sieve-tube element?
A companion cell, which is connected to the sieve-tube element by plasmodesmata
98
The nucleus and ribosomes of the companion cell serve as the _____ _____ and as a _____ ____ ____ ____
cell itself; sieve tube element
99
Without the companion cell, the sieve-tube member would _______, ceasing phloem function, and thereby killing the plant.
die
100
Where are xylem vessel elements (tracheae) typically found and where are they absent?
found in angiosperms, absent from gymnosperms
101
What is a type of tissue found in plants that consists of undifferentiated cells capable of cell division?
Cells in the _____ can develop into all the other tissues and organs that occur in plants.
Meristem
102
When do cells stop dividing?
When they get differentiated
103
Where are apical meristems located?
Root and shoot tips
104
What growth do apical meristems enable?
primary growth (growth in length)
105
What growth do lateral meristems enable?
secondary growth (growth in width)
106
What three tissue types are the primary meristems and what do they do?
Protoderm - produces dermal tissue system
Ground meristem - produces ground tissue system
Procambium - produces vascular tissue system
107
What are the lateral meristems?
Vascular cambium and cork cambium
108
What does the vascular cambium do?
Adds vascular tissue and secondary xylem (wood - thick) and secondary phloem
109
What does the cork cambium do?
Replaces the epidermis with the thicker, tougher periderm
110
What do apical meristems at root tips do?
Primary growth (in length) makes roots extend throughout the soil
111
What includes the stem cells of the root
| apical meristem and their immediate products? What's produced here?
The zone of cell division, where new root cells
| are produced, including cells of the root cap.
112
What protects the delicate apical
| meristem as the root pushes through the abrasive soil?
Root cap
113
Annuals complete their entire life cycle (germination, flowering, seed production, and death) in a ____, biennials complete their life cycle in ______, and perennials live many years. They don't die from old age but from ______ ______
infection or environmental trauma
114
Cells that remain as wellsprings of new cells in the meristem are called......
Initials
115
Cells that are displaced from the meristem that continue to divide for some time until the cells they produce differentiate within developing tissues are called.....
Derivatives
116
What does the root cap secrete?
polysaccharide slime that lubricates the soil around the growing root tip.
117
What are the three zones of cells at successive stages of primary growth called?
1. Zone of cell division (includes root apical meristem, new cells produced here)
2. Zone of elongation (cells elongate 10x their length to push the root tip and the meristem ahead)
3. Zone of maturation (cells become differentiated and functionally mature)
118
Water and minerals absorbed from the soil must enter through the...... (plus how many layers)
epidermis, a single layer of cells covering the root
119
a group of cells where cell division proceeds very slowly or not at all, but the cells can resume meristematic activity when the tissue surrounding them is damaged.
Quiescent center
120
Innermost layer of the cortex.....
Endodermis
121
An established root may sprout ________ from the outermost layer of the vascular cylinder, the pericycle.
lateral roots
122
What waterproofs the cells of the cork cambium?
Suberin
123
Cork is the _____ tissue of the stem or root
outermost
124
Eudicot stele shape in roots
Xylem +, Phloem around +, pericycle is layer that lateral roots emerge from
125
Monocot stele shape in roots
Xylem surrounds pith, phloem is around xyxlem
126
The vascular cambium forms successive layers of secondary xylem to its ______ and secondary phloem to its ______.
interior, exterior
127
The vascular cambium develops from what cells?
Parenchyma cells
128
Tree trunks from temperate regions show annual rings that result from seasonal conditions. What happens during the spring with an abundance of water?
Tracheids/vessel elements have larger diameters and thinner walls, more water flow to leaves
129
What happens during the summer with less water?
smaller diameter cells with thicker walls are produced
