Chapter 10: plants Flashcards
Imbibition
Absorption of water by seed ~ breaks seed coat
Meristem
an area of plant takes place through repeated cell division
Apical meristem
Grows vertically ~ increases height Primary Growth (all plants)
Two types of meristem
Apical and lateral
Lateral meristem
Grows horizontally ~ increase width/thickness Secondary Growth (woody plants)
Three zones at apical meristem
Zone of division : constant division
Zone of elongation: absorption of water
Zone of maturation: differentiation into specific plant tissues
Vascular cambium:
ring of meristemic tissue located between primary xylen & phloem
- Cells produced outside ~ become secondary phloem
- Cells produced inside ~ become secondary xylem
Secondary Xylem:
along with pith ~ form wood.
- Constant production ~ forms growth rings
Secondary phloem:
bark, cork cambium, cork
- Replaces the older ones.
Cork cambium:
ring of meristemic beyond the phloem.
Ground tissue:
Parenchyma, Collenchyma, Sclerenchyma
Parenchyma:
Filler tissue
Collenchyma:
Extra support to plant
Sclerenchyma:
main structural support
Phloem
Transports sugars
- sieve & companion cells
Sieve
allows substances to flow through them
lack organelles
Companion cells
carries out metabolic functions
have organelles
* connected via plasmodesmata
Xylem
Transports water in unidirectional
- Tracheids & vessel elements
Tracheids
Overlap their tapered ends.
Form tracheid to tracheid through pits
Vessel elements:
Vessel to vessel through perforation
Both xylem & phloem arrange to form
Stele (central part of the root)
Pith
Tissue found in center of root or stem.
- Made up of parenchyma
Stores and transports materials.
Epidermis
waxy layer ~ cuticle
Root hairs
Increase surface area - greater water & nutrient uptakes.
Cuticle - limits evaporation
Symplastic pathway - water movement through cell’s cytoplasm
Apoplastic pathway - water movement outside the cell (cell wall)
Casparian strip
regulate type & amount of substance that can enter from roots to the rest of the plant.
- fatty, waxy substance ~ impenetrable.
Function of stomata
gas exchange (open & close)
Function of guard cells
control opening & closing of stomata