tissues Flashcards
parenchyma cells
large undifferentiated cells with thin primary cell walls.
alive at maturity, thin walled cells that make up inside of non woody plant structures including stems, roots, and leaves. They are totipotent, meaning they can develop in a whole plant
collenchyma cells
unevenly thickened primary cell wall for support, especially in growth areas, surround vascular tissue
sclerenchyma
evenly thickened lignified secondary cell walls for support and conduction
types of parenchyma:
chlorenchyma, aerencgyma, prosenchyma, mesophyll parenchyma, xylem parenchyma, epidermal parenchyma
Prosenchyma-
specialized paraenchyma that are long tapered lignified and used for storage
aerenchyma
air holes created to make it a spongy cross section, helps make O2
parenchyma transfer cell function
associated with phloem cells, numerous wall ingrowths, helps move water/carbohydrates
sclerids
have highly thickened, lignified, cellular walls that form small bundles of tissue, can be branched
where does primary growth occur?
shoot and root apical meristems where parenchyma cells divide into primary meristems
how are primary meristems differentiated
becomes the protoderm, ground meristem, and pro cambium
what do ground tissue consist of
parenchyma, sclernchyma, and collenchyma
dicot cross section
surrounded by cuticle, palisade layer and mesophyll in the middle, lower and upper epidermis at the ends
guard cell function
flank the stoma, where water exits to close stoma
subsidiary cells
support cells for stoma
what do epidermal cells differentiate into?
trichomes
trichome function
reduce water loss and protect against herbivory
cells associated with xylem
tracheary elements that conduct water and minerals, fibers for support and sometimes storage, and parenchyma for storage
cells associated with phloem
sieve elements for long distance transport of food materials,
sclerenchyma, sclerids, fibers, and parenchyma for storage
what do meristematic cells differentiate into
vessel elements with secondary cell walls, sieve tube elements, fibers and parenchyma
describe the vascular cylinder in roots
xylem tissue in the middle surrounded by sclerenchyma cells
how do sugar move in phloem tissue
with the help of water
tracheid and vessel element development
tracheids first developed evolutionarily, then vessel tube elements developed
vessel elements found in angiosperms but not gymnosperms
process of vessel development
parenchyma cell develops, secondary wall thickens, nucleus degenerates, primary wall disintegrates
process of phloem development
companion cells present next to sieve tube elements, since putting sugar in is an energy intensive process
- water enters sieve tube element
- sieve plates present at end, lateral area present to push water in laterally
albuminous cells
have same function as companion cells in gymnosperms
