Plant Structure- Roots, Stems, Leaves Flashcards
Roots
Epidermis
Cortex
Endodermis
Vascular Cylinder
Epidermis of Root
Lines outside surface of root and produces root hairs in the zone of maturation to increase absorption
Root hairs die as the zone of maturation ages, requiring constant growth of the root to produce more
Cortex of Root
Bulk of the roots
Stores starch
Endodermis of Root
Ring at the inner cortex
Contains the casparian strip
Casparian Strip
Band of fatty matterial (suberin)
Creates a water impermeable barrier between cells
Result of Castrian Strip
Water passing through endodermis must pass through endodermal cells (not between cells)
Allows for endodermal cells to control movement of water into center of root (where vascular tissue resides) and prevent water movement back out to cortex
Vascular Cylinder (Stele) of Root
Tissues inside endodermis
Pericycle
Outer part of vascular cylinder
Where lateral roots arise from
Iside pericycle is the vascular tissue
Structure of Stem
Similar to root, but no casparian strip or endodermis (specialized for water absorption, only happens in root)
Epidermis of Stem
Contains epidermal cells covered with waxy cutin substance
Cutin forms the cuticle
Contains guard cells around stomata, and stinging cells
Cortex of Stem
Ground tissue containing chloroplasts
Bulk of substance lying between epidermis and vascular cylinder
Vascular Cylinder of Stem
Contains xylem, phloem, and pith
Single layer of cells between xylem and ploem may remain undifferntiated and later become the vascular cambium
Structure of Leaf
Epidermis
Palisade mesophyll
Spongy mesophyll
Vascular bundle
Stomata
Epidermis of Leaf
Protective covering
Covered by the cuticle, which reduces transpiration (water loss)
Specialized epidermal cells can contain trichomes
Palisade Mesophyll
Parenchyma cells containing chloroplasts (sites of photosynthesis)