Lecture 24 - Plant Growth & Development (part 1) Flashcards
1
Q
What are plants composed of?
A
cells, tissues & organs
2
Q
What is a shoot system?
A
above ground organs of the plant
3
Q
What are stems composed of (within the shoot system)?
A
- Nodes
- Internodes
- Shoot apical meristem (SAM)/Apical buds terminal bud)
- Axillary buds
4
Q
What are leaves composed of (within the shoot system)?
A
- Blades
- Petioles
- Veins
5
Q
What is a root system?
A
below ground organs of the plant
6
Q
What are root systems composed of?
A
- Taproots (eudicots)
- Lateral roots
- Root hairs
- Root apical meristem (RAM)
7
Q
What is the dermal tissue system?
A
protective tissue layer
8
Q
What is the dermal tissue system comprised of?
A
- epidermis
- cuticle
- periderm
- guard cells
- trichomes
9
Q
Epidermis
A
outermost cell layer
- within the dermal tissue system
10
Q
Cuticle
A
waxy, protective layer on stems and leaves
- within the dermal tissue system
11
Q
Periderm
A
layer in woody plants that REPLACES the epidermis during secondary growth
- within the dermal tissue system
12
Q
Guard cells
A
gas exchange
- within the dermal tissue system
13
Q
Trichomes
A
hairlike cells that reduce water loss, reflect excess light, defense
- within the dermal tissue system
14
Q
What is the vascular tissue system?
A
transport tissue layer
15
Q
What is the vascular tissue system comprised of?
A
- Xylem
- Phloem
- Stele
16
Q
Xylem
A
water conducting tissue
- within the vascular tissue system
17
Q
Phloem
A
transports photosynthates
- within the vascular tissue system
18
Q
Stele
A
xylem + phloem
- within the vascular tissue system
19
Q
What is the function of the ground tissue?
A
storage, support, & photosynthetic tissue layer
20
Q
What is the ground tissue system comprised of?
A
- Pith
* Cortex
21
Q
Pith
A
internal to vascular tissue
- within the ground tissue system
22
Q
Cortex
A
external to vascular tissue
- within the ground tissue system
23
Q
Describe Parenchyma cells
A
- THIN and FLEXIBLE primary cell walls
- LACK secondary cell walls
- Large central VACUOLE
- Perform most of the METABOLIC functions of the plant
- LIVING cells
24
Q
Chlorenchyma
A
photosynthetic parenchyma
• Some contain amyloplasts, which STORE STARCH
• Can divide and differentiate to REPAIR TISSUES
- within parenchyma cells
25
Describe Collenchyma cells
* GROUPED in strands, usually BENEATH the EPIDERMIS
* SUPPORTIVE function, flexible but NOT restrictive
* ELONGATED CELLS with UNevenly thickened primary cell walls
* LIVING cells
26
Describe Sclerenchyma cells
* Contain secondary cell walls composed of lignin
* Functionally dead at maturity
* Very rigid, structural support
* Sclerids
* Fibres
27
Sclerids
```
irregular shaped (gritty texture in pears)
- within schlerenchyma cells
```
28
Fibres
Long, slender strands, tapered (hemp fibres)
| - within schlerenchyma cells
29
What is apart of Xylem Tissue?
* Tracheids
| * Vessel Elements
30
What is Tracheids (within Xylem Tissue)?
* Tubular, elongated cells with tapered ends
* IN the XYLEM of all vascular plants
* DEAD at maturity, thickened secondary CELL WALLS of LIGNIN
* Water moves BETWEEN cells VIA PITS
31
What is Vessel Elements (within Xylem Tissue)?
* Wider, shorter elongated cells with less tapering
* ALIGNED end-to-end with PERFORATION PLATES
* IN THE XYLEM of angiosperms, a few gymnosperms, and a few seedless vascular plants
* DEAD at maturity, thickened secondary CELL WALLS OF LIGNIN
32
What is apart of Phloem Tissue?
* Sieve-tube elements
| * Companion cells
33
What is Sieve-tube elements (within Phloem Tissue)?
* ALIVE, but LACK a nucleus, ribosomes, cytoskeleton, vacuole
* Long, narrow cells CONNECTED by SIEVE PLATES
34
What is Companion cells (within Phloem Tissue)?
* CONNECTED TO the sieve-tube element
* NON-conducting
* Contains a NUCLEUS & ALL organelles
* Metabolic products are transferred from here TO the sieve-tube elements
35
What is responsible for growth?
meristems
36
Growth is not limited to...
juvenile or embryonic stages
37
Determinate growth
* Some plant organs stop growing after a certain size
| * Similar to that of animals
38
Indeterminate growth
Plants keep growing throughout their life DUE TO MERISTEMS
39
Apical meristems
* Tips of roots, shoots and in axillary buds
| * Enable primary growth (increases height)
40
Lateral meristems
Enables secondary growth (increases girth, wideness)
- Vascular cambium
- Cork cambium
41
Vascular cambium
Adds secondary xylem and secondary phloem to the organ
| - within the lateral meristems
42
Cork cambium
Replaces the epidermis with periderm as it cracks and sloughs off
- within the lateral meristems
43
Describe the meristems division
Divide frequently during the growing season
• Some cells remain meristematic (initials/stem cells)
• Most cells will differentiate into cell types, tissues, and organs
44
The root is derived from the____, which is covered by a _____ which protects the _____ from damage as the root elongates
- RAM (root apical meristem)
- root cap
- RAM (root apical meristem)
45
What is the 3 primary growth in roots?
* Zone of Division
* Zone of Elongation
* Zone of Differentiation
46
Describe Zone of Division
* Includes the stem cells/initials of the RAM (root apical meristem)
* Produces new root cells, including cells in the root cap
47
Describe Zone of Elongation
* Most of the “growing” region of the root
* Cell elongation pushes the root tip further DOWN INTO THE SOIL
* 3 tissue systems begin to develop
48
Describe Zone of Differentiation
* Aka zone of maturation
| * Cell differentiation into specific cell types
49
What is the outmost primary meristem that will give rise to the epidermis?
the protoderm
50
Ground tissue consists of mostly ______ cells & is found in the _____ & is created via the _____ _____
- parenchyma
- cortex
- ground meristem
51
What gives rise to the vascular cylinder (stele)?
procambium
52
Describe what is included in the procambium
* Pericycle is the innermost layer of cells right inside of the endodermis
* Lateral roots arise from the pericycle
53
Describe Pericycle
is the innermost layer of cells right inside of the endodermis
54
Lateral roots arise from the...
pericycle
55
Compare & contrast a root with xylem & phloem in the centre (typical of eudicots) to a root with parenchyma in the centre (typical of monocots)
- Vascular tissues in X shape
- Less thick endodermis
- No pith
- Vascular tissues in rings
- Thick endodermis (suberized)
- Pith present
56
The shoot is derived from the ____, which is protected by the leaves of the _____ ____
- SAM
| - apical bud
57
What is shoot elongation due to?
the lengthening of the internodes
58
SAM gives rise to the same primary meristems as the root, which are...
protoderm, ground meristem, procambium
59
Branching arises from...
axillary buds (each with their own apical meristem)
60
Apical dominance
plant hormones prevent buds close to the apical meristems from growing
61
Leaf primordia arise from the...
flanks of the SAM
62
The stem is covered by an...
epidermis containing a cuticle
63
The ground tissue mostly consists of _____, with ____ layers of ________ directly under the epidermis.
Schlerenchyma fibres may also be found to add additional _______ & _________.
- parenchyma
- 1-2
- collenchyma
- structure
- support
64
Vascular tissue runs from the _____ ______ ______ all the way up the _____ in _______ bundles
- root vascular cylinder
- stem
- continuous
65
Compare & contrast a cross section of stem with vascular bundles forming a ring (typical of eudicots) to a cross section of stem with scattered vascular bundles (typical of monocots)
- vascular bundles arranged in a ring
- pith present in the center
- no pith
- vascular bundles scattered
66
Leaves develop from _______ that flank the SAM
leaf primordia
67
What are the 3 primary meristems that give rise to leaf tissues?
* Protoderm
* Ground meristem
* Procambium
68
Protoderm
epidermis with a thick cuticle
69
What is protoderm interrupted by?
stomata (sing. Stoma) surrounded by guard cells
70
Ground meristem
gives rise to mesophyll (“middle leaf”)
71
What is Ground meristem composed of?
* Composed of specialised parenchyma cells called chlorenchyma
* Palisade mesophyll
* Spongy mesophyll
72
Palisade mesophyll
elongated parenchyma on the upper part of the lead
73
Spongy mesophyll
loosely arranged parenchyma with large air spaces for movement of CO2/O2 gases
74
Vascular tissue is _____ with the vascular tissue in the ____
- continuous
| - stem
75
The vascular tissue in the leaves is contained in...
“bundles” called veins, surrounded by a bundle sheath composed of parenchyma cells
76
What are the 3 primary meristems?
1. Protoderm
2. Ground Meristem
3. Procambium
77
Blades
flattened part of the leaf for photosynthesis
78
Petioles
joins the blade to the stem
79
Veins
vascular tissues
80
Taproots
(eudicots), main vertical root
81
Lateral roots
sides roots
82
Root hairs
extensions of epidermal hairs for increased absorption
83
Root Apical Meristems (RAM)
increases root length
84
Nodes
leaf attachment points
85
Internodes
stem b/t leaves
86
Shoot Apical Meristems (SAM)/Apical Buds
grows up (AKA terminal buds)
87
Axillary buds
can form lateral branches, thorns, flowers
