anatomy, morphology, & growth of angiosperms – ch. 5-8
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Anatomy, Morphology, & Growth of Angiosperms – Ch. 5-8. Two plant groups: monocots & dicots. Muscle cell. Cells. Tissues. Muscle tissue. Organs. Heart. Circulatory system. Systems. The Plant Cell. Fig 7.8. 5 Differentiated Plant Cell Categories. Parenchyma Collenchyma Schlerenchyma - PowerPoint PPT PresentationTRANSCRIPT
Anatomy, Morphology, & Growth Anatomy, Morphology, & Growth of Angiosperms – Ch. 5-8of Angiosperms – Ch. 5-8
Two plant groups: monocots & dicots
Cells
Tissues
Organs
Systems
Muscle cell
Muscle tissue
Heart
Circulatory system
The Plant Cell
Fig 7.8
5 Differentiated Plant Cell Categories
1. Parenchyma2. Collenchyma3. Schlerenchyma4. Water-conducting cells of the xylem5. Sugar-conducting cells of the phloem
1. Parenchyma
• thin and flexible cell walls
2. Collenchyma
• Usually grouped in strands to support young parts of plants without restraining growth
• Flexible, elongate with growing shoots
3. Schlerenchyma
• May be dead at functional maturity – ??? • cell walls left behind as skeleton
4. Water conducting cells of the xylem:
• 2 types: tracheids & vessel elements
Tracheids
• Water flows from cell to cell (laterally) through pits in cell wall
• Support function
Vessel Elements
• End walls are perforated for free flow of water• More efficient as water conductors than tracheids
Fig 35.9
5. Sugar-conducting cells of the phloem
Sieve-tube members:
• Lack a nucleus, ribosomes, vacuole• Cells separated by perforated sieve plates –
allow sugar movement
Fig 35.9
Three main tissues: Dermal,
Vascular, Ground
Fig 35.8
1. Dermal tissue or epidermis
• Root hairs are specialized epidermal extensions• Secretes waxy cuticle of the leaf
2. Ground Tissue
• fills the space between dermal and vascular tissue systems.
• Diverse functions:
pith
cortexIn dicots:
3. Vascular Tissue
• function in transport between roots & shoots, and structural support of plant– Xylem:
– Phloem: Food transported to roots & non-photosynthetic parts such as the flowers
Growth & Development
http://www.cneccc.edu.hk/subjects/bio/album/Chapter20/PLANT_GROWTH.html
• Development =
Three processes of development:
1. Growth =
2. Cellular differentiation = generation of different cell types
3. Morphogenesis – creation of body form & organization.
1. Growth
• Cell division no expansion
• = due to water uptake in the vacuole
Growth
Fig 35.24
Cell division
• Occurs in only in meristems!
Meristems• =
• Two types of meristems:1. Apical meristem –
2. Lateral meristems – extend lengthwise along the axis of the stem & roots. Responsible for growth in girth in older parts of the plant (called secondary growth). Exist only in perennials
Fig 35.10
Arrangement of Primary Tissues in Roots1. Epidermis –
2. Stele –
3. Ground tissue – mostly parenchyma cells of the cortex – area between the stele & epidermis; stores food & takes up minerals.
• Endodermis – single cell layer between cortex & stele. Selective barrier for uptake of soil solution contents into vascular system.
Fig 35.13
Epidermis
Cortex
Endodermis
Stelexylem
phloem
Eudicot/Gymnosperm root cross section
Primary Growth of Shoots
• Bud = cluster of leaf primordia created by meristem. No internodes
• Lateral branches arise from axillary buds
Fig 35.15
Primary tissue arrangement of stems
– Ground tissue = pith & cortex
Fig 35.16
pith
cortex
epidermis
phloem
xylem
Schlerenchyma cells
Eudicot/Gymnosperm stem cross section
Tissue arrangement of leaves
• 3 parts:1. Upper & lower epidermis – tightly interlocked cells,
secrete waxy cuticle. Contains stomata flanked by guard cells
2. Vascular tissue –
3. Mesophyll – ground tissue between upper & lower epidermis
Fig 35.17
Secondary Growth
• Two lateral meristems:1. Vascular cambium – produces secondary
xylem (= wood) & phloem2. Cork cambium – replaces the epidermis with
cork: tough, thick cover for stems, roots.
Secondary growth of stems• Vascular cambium – layer of cells between
primary xylem & primary phloem. Puts on successive layers of secondary phloem to outside & secondary xylem to inside =====> stem widens
• Wood = accumulation of secondary xylem. Dead at maturity, contains lignin
What is bark?• “bark” =
• Cork continually sloughs off
Fig 35.18
Fig 35.20
Three types of life cycles:
1. Annual –
2. Biennial – complete life cycle in two years (first year = vegetative, second year = reproductive). Some need a cold winter period to initiate flowering from vegetative state. Ex. carrots
3. Perennial – live year after year, do not die after reproduction. Examples: trees, shrubs, some grasses. Causes of death = fire, disease