plant form chapter 36. plant classes seed producing plants: –gymnosperms –angiosperms...
TRANSCRIPT
Plant Form
Chapter 36
Plant Classes
• Seed producing plants:– Gymnosperms– Angiosperms
• Dicotyledons (dicots)
• Monocotyledons (monocots)
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Plant Classes
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Plant Body Organization
All vascular plants consist of:
• Root system
• Shoot system
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• 3 basic tissue types
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DermalGround
Vascular
Plant Growth
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• Adult cell growth is limited.• Growth and development of adult plants is dependent on specialized cells called meristems.
Apical Meristem• Located at tips
of stems and roots.
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Lateral Meristem
• Produce wood and bark in trees and bushes – called secondary growth.
Vascular Tissue - Xylem
• Main water-transportation tissue
• Also transports dissolved minerals, NO3
and PO4.
• Provides stem support.
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• Principal food-conducting tissue in vascular plants
• Carries glucose and starch created during photosynthesis
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Vascular Tissue - Phloem
Roots
• Four regions are commonly recognized:
– Root cap
– Zone of cell division
– Zone of elongation
– Zone of maturation
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Stages in the differentiation of plant tissues
Modified Roots
• Most plants produce either/or:– Taproot system – single large root with small
branch roots– Fibrous root system – many small roots of
similar diameter– Some plants, however, produce modified
roots with specific functions– Adventitious roots arise from any place other
than the plant’s root
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Prop roots Aerial roots
Pneumatophores Water storage roots
Buttress roots
Stems
• Undergo growth from cell division in apical and lateral stems
• Shoot apical meristem cells create stem tissue as well as leaves, other shoots, and flowers.
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Parts of the Stem
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Monocot stemEudicot (Dicot) stem
Leaves
• Principal site of photosynthesis
• Expand by cell division and cell enlargement
• Growth stops at maturity
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Leaf Structure
•Cuticle•Epidermis•Palisade mesophyll•Spongy mesophyll•Vascular bundles•Guard cells•Stoma
Modified Leaves
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Bracts
Spines
Insectivorous
Reproductive