plant structure, growth, & development campbell and reece chapter 35 campbell and reece chapter...
TRANSCRIPT
![Page 1: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/1.jpg)
Plant Structure, Growth, & Development
Campbell and ReeceChapter 35
![Page 2: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/2.jpg)
Organization of Plants
• Plants like most multicellular organisms have organs made of tissues that are made of different cell types
![Page 3: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/3.jpg)
3 Basic Plant Organs
1. Stems2. Roots3. Leaves
![Page 4: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/4.jpg)
Roots
• Organ that 1. anchors a
vascular plant in the soil
2. absorbs water & minerals
3. stores carbohydrates
![Page 5: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/5.jpg)
Taproot System
• In most eudicots & gymnosperms
• Taproot develops from embryonic root
• Forms lateral roots (branch roots)
• Penetrate deep• Eudicot: most flowering
plants that have 2 embryonic seed leaves
• Gymnosperm: vascular plant that bears naked seeds
![Page 6: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/6.jpg)
Roots in Monocots
• Grasses: no tap root• Roots called adventitious: grows
in unusual locations– Example: roots arising from stems
or leaves
![Page 7: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/7.jpg)
Adventitious Root Systems
• Each small root forms its own lateral roots fibrous root system
![Page 8: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/8.jpg)
Root Hairs
• Emerge near tips of roots• Increase surface area for
absorption of water and mineral ions (do not help anchor plant)
• are thin, tubular extensions of a root epidermal cell
![Page 9: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/9.jpg)
Root Adaptations
• Prop Roots: support tall, top-heavy trees
• Pneumatophores: air roots, portion above water line allows them to get O2
![Page 10: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/10.jpg)
Root Adaptations
• Buttress Roots: tallest trees in rain forest have shallow roots; buttress roots give support to trunks
• “Strangling” Aerial Roots: seeds of these trees (strangler fig) germinate in branches of host tree
![Page 11: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/11.jpg)
Stems
• Plant organs that 1. raise or separate leaves
allowing them to receive more sunlight
2. Raise reproductive structures facilitating dispersal of seeds or pollen
![Page 12: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/12.jpg)
Parts of a Stem
• Each stem has alternating system of:1. Nodes– Pts @ which leaves are attached
2. Internodes – Stem segments between nodes
3. Axillary Bud– Upper angle (axil) formed by each leaf
& stem– Structure that can form a lateral shoot
(branch)
![Page 13: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/13.jpg)
Parts of a Stem
4.Apical Bud– Part of shoot tip– The terminal bud (where most of
growth occurs)
5. Apical Dominance– Inhibits growth @ axillary buds– If eaten by herbivore or if light
more intense @ side of a shoot axillary buds break apical dominance & grow
![Page 14: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/14.jpg)
Why Pruning Makes a Plant Bushier
![Page 15: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/15.jpg)
Parts of a Stem
![Page 16: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/16.jpg)
Adaptations of Stems
1. Rhizomes: horizontal shoots that grow just below surface ;vertical shoots emerge from axillary buds
• Ex: Irises, Hops
![Page 17: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/17.jpg)
Stem Adaptations
2.Bulbs: are vertical, underground shoots made mostly of enlarged bases of modified leaves that store food
• Ex: onion, tulips
![Page 18: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/18.jpg)
Adaptations of Stems
3. Stolons: horizontal shoots that grow along surface; aka “runners”
• Enable plant to reproduce asexually: plantlets form @ nodes
• Ex: strawberries, some grasses
![Page 19: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/19.jpg)
Adaptations of Stems
4. Tubers: enlarged ends of rhizomes or stolons specialized for storing food. “Eye” of potato is cluster of axillary buds that mark the nodes
Ex: potato, dahlias
![Page 20: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/20.jpg)
Leaves
• In most plants leaf is main photosynthetic organ
• General Structure:– Blade– Petiole • not on grasses or most monocots
– Veins • Patterns differ monocots & eudicots
![Page 21: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/21.jpg)
Structure of a Leaf
![Page 22: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/22.jpg)
Types of Leaves
![Page 23: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/23.jpg)
Leaf Adaptations
• Tendrils: modified leaf used to support plant
• Ex: pea plants
• Some plants have tendrils that are modified stems (grapevines)
![Page 24: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/24.jpg)
Leaf Adaptations
2. Spines: leaves adapted for protection
In cacti, stems are main photosynthetic organ
![Page 25: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/25.jpg)
Leaf Adaptations
3. Storage Leaves: most succulents have leaves adapted to store water
![Page 26: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/26.jpg)
Leaf Adaptations
4. Reproductive Leaves: leaves of some succulents produce adventitious plantlets which fall off & take root in soil
Ex: some succulents
Hens and Chicks
![Page 27: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/27.jpg)
Leaf Adaptations
5. Bracts: modified leaves surrounding the real flower; function: attract pollinators
The yellow portion of poinsettia is the flower; the red leaves are bracts
![Page 28: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/28.jpg)
Tissue Systems
• Are functional units connecting all of the plants organs
![Page 29: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/29.jpg)
Dermal Tissue System
• Plant’s outer protective covering:
• Epidermis: nonwoody plants: tightly packed cells
• Cuticle: waxy covering on epidermal surface prevents water loss
• Periderm: in woody plants: replaces in older regions of stems & roots
![Page 30: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/30.jpg)
Vascular Tissue System
Carries out long-distance transport of materials between the root & shoot systems
1. Xylem– H2O & dissolved
materials roots shoots
2. Phloem– Sugars roots &
sites of growth
![Page 31: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/31.jpg)
Ground Tissue System
• Tissue that isn’t dermal or vascular tissue
• Pith: Internal to vascular tissue
• Cortex: external to vascular tissue
![Page 32: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/32.jpg)
Plant Cells
• Cell differentiation involving changes in:– Cell walls– Cytoplasm–Organelles
![Page 33: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/33.jpg)
Parenchymal Cells
• Mature cells have thin, slightly flexible cell walls (only 1)& large central vacuole
• Functions:– Perform most of metabolic
functions of plant• Chloroplasts• Plastids: store starch, found in roots• Make up most of fleshy part of fruits• Most able to divide & differentiate into
other cell types
![Page 34: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/34.jpg)
![Page 35: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/35.jpg)
Collenchyma Cells
• Come grouped in strands just below epidermis
• Support young parts of plant shoot w/out interfering with growth
• Elongated cells with thicker cell walls (compared to parenchymal cells) which can be irregularly thickened
• Remain living cells thru out plant life
![Page 36: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/36.jpg)
![Page 37: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/37.jpg)
Sclerenchymal Cells
• Supportive role but more rigid than collenchymal cells in regions of plant that have stopped growing
• 2º cell walls thick, contain lignin (>1/4 dry mass of wood)Lignin in all vascular plants, not in bryophytes
• Many dead at plant maturity: rigid cell walls support plant
![Page 38: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/38.jpg)
Sclerenchymal Cells
• 2 types: (both for support & strength)
1. Sclereids– Boxy, irregularly shaped cells– Thick lignified 2º cell walls– Hardness in nutshells/grittiness in pear
2. Fibers – Grouped in strands– Long, slender, tapered– Hemp fibers for rope/flax fibers for linen
![Page 39: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/39.jpg)
![Page 40: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/40.jpg)
Water-Conducting Cells of Xylem
• 2 types: both elongated, tubular cells/dead at plant maturity: form tubular conduit for water flow; have pits thru which water can move laterally
1. Tracheids– In nearly all vascular plants
2. Vessel Elements– In some vascular/most
angiosperms/few gymnosperms
![Page 41: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/41.jpg)
![Page 42: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/42.jpg)
Sugar-Conducting Cells of the Phloem
• 4 types all alive @ plant maturity1. Sieve Cells: in seedless vascular plants &
gymnosperms2. Sieve Tubes: chains of cells/ enucleated,
no ribosomes, vacuole, or cytoskeleton sugars can diffuse thru cell more easily
3. Sieve Plates: pores for flow of sap fluid cell-to-cell
4. Companion Cells: nonconducting cells connected to sieve tube cells by plasmodesmata/their ribosomes & nucleus serve both cells
![Page 43: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/43.jpg)
![Page 44: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/44.jpg)
![Page 45: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/45.jpg)
Growth in Plants
![Page 46: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/46.jpg)
Stem Growth
![Page 47: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/47.jpg)
Root Growth
![Page 48: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/48.jpg)
Cross-Section of a Leaf
![Page 49: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/49.jpg)
Anatomy of a Tree Trunk
• bark includes all tissues external to the vascular cambian (2º xylem, wood, and phloem)
• Sapwood = “living wood” has lighter color than heart wood (center) which is made of dead cells
![Page 50: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/50.jpg)
![Page 51: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/51.jpg)
Development of a Plant• Definitions:• Development: specific series of
changes by which cells form tissues, organs, & organisms
• Growth: irreversible increase in size
![Page 52: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/52.jpg)
More Definitions
• Morphogenesis:cellular & tissue-based processes by which an organism takes shape, depends on cells responding to positional information from neighboring cells
• Differentiation : process by which a cell or group of cells become specialized in structure & function
![Page 53: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/53.jpg)
Plant Cell Division
• Preprophase band made of microtubules develops in late interphase determines where cell plate will form
![Page 54: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/54.jpg)
Asymmetrical Cell Division
• not all plant cells divided equally duting M Phase of cell cycle
• When occurs: usually signals a key event in development
• Example:– Epidermal cell divides • 1 large epidermal cell• 1 small guard cell
![Page 55: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/55.jpg)
Cell Polarity
• The condition of having structural or chemical differences at opposite ends of an organism
• Typical plant has axis with a shoot end & a root end– 1st division of fertilized plant ova
asymmetrical which initiates polarization of plant body into shoot & root
![Page 56: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/56.jpg)
• Cell division enhances possibility of plant growth but it is cell elongation that is responsible for plant growth
Cell Elongation
![Page 57: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/57.jpg)
Cell Elongation
• Controlled by microtubule orientation controls the orientation of cellulose microfibrils in cell wall
![Page 58: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/58.jpg)
Cell Differentiation
• Arises from differential gene activation
• Enables cells w/in plant to assume different functions
• Way any particular cell differentiates depends on its position in developing plant
![Page 59: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/59.jpg)
![Page 60: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/60.jpg)
Pattern Formation• Is the development of specific
structures in specific locations• 2 hypothesis to explain1. Lineage-based mechanism– Daughter cells have instructions
from early cells in plant development
2. Position-based mechanism– Cell’s position in emerging organ
determines what kind of cell it will become
![Page 61: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/61.jpg)
Pattern Formation
• Position-based hypothesis– By destroying cells during
development have shown that cell’s fate determined late in development & depends mostly on signals from neighboring cells
– Cell fate in animals mostly lineage-dependent involving transcription factors
![Page 62: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/62.jpg)
Pattern Formation
• Hox genes–Homeotic genes that code for
transcription factors – Critical for proper # & placement of
embryonic structures (legs, antennae in Drosophila)
![Page 63: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/63.jpg)
Pattern Formation
• Knotted-1 homologous to Hox gene found in maize
• Important in development of leaf morphology
![Page 64: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/64.jpg)
Control of Cell Differentiation
• Depends on control of gene expression: which genes are transcribed protein
• But fate of a particular cell is determined by its final position in the developing organ, not by cell lineage– If undifferentiated cell is misplaced
it will differentiate into cell type appropriate to its position
![Page 65: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/65.jpg)
Activation of Genes
• Depends on signals from neighboring cells
![Page 66: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/66.jpg)
Phase Changes
• Cues from plant itself or from its environment cause plant to switch from 1 developmental stage to another: called Phase Changes
• Most obvious changes in leaf shape & size
![Page 67: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/67.jpg)
![Page 68: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/68.jpg)
Genetic Control of Flowering
• Flower formation involves phase change from vegetative growth reproductive growth
• transition triggered by:1. Environmental cues– Length of daylight2. Internal signals– Plant hormones
![Page 69: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/69.jpg)
Genetic Control of Flowering
• Production of a flower by a shoot apical meristem stops the primary growth of the shoot
• Is ass’c with the switching on of floral meristem identity genes
• Meristem: plant tissue that remains embryonic as long as plant live, allowing for indeterminate growth
![Page 70: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/70.jpg)
![Page 71: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/71.jpg)
Meristem Identity Genes
• Code for transcription factors that regulate genes needed for conversion of the indeterminate vegetative meristems determinate floral meristems
![Page 72: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/72.jpg)
Organ Identity Genes
• A plant homeotic gene that uses positional information to determine which emerging leaves develop into which type of floral organs
![Page 73: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/73.jpg)
![Page 74: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/74.jpg)
Organ Identity Genes
• Provide model system for studying pattern formation:– The development of a multicellular
organism’s spatial organization: arrangement of organs & tissues in their characteristic places in 3-D
![Page 75: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/75.jpg)
Organ Identity Genes
• 3 classes identified by studying mutants with abnormal flowers
• ABC Hypothesis• A model of flower formation
identifying 3 classes of organ identity genes that direct formation of the 4 types of floral organs
![Page 76: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/76.jpg)
![Page 77: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/77.jpg)
• http://www.slideshare.net/jayswan/chapter-35-presentation
![Page 78: Plant Structure, Growth, & Development Campbell and Reece Chapter 35 Campbell and Reece Chapter 35](https://reader036.vdocuments.net/reader036/viewer/2022062518/56649e355503460f94b24094/html5/thumbnails/78.jpg)