Biolab 3: Leaves Flashcards
chlorenchyma
cells iwth chlorophlats
epidermis
protective layers on both teh top and bottom, also allows the passage of carbon dioxide and oxygen
mesomorphic leaf
requring moderate amounts of water regularly through the growing season
top of the leaf
upper epidermis
lower epidermis
bottom layer
all the cells middle of the leaf
mesophyll
upper epidermis
wraps around the leaf and is continous with the lower epidermis , packed cells that prevent excessive water loss and provide mechanical support
cuticle
outer walls of the cells are covered by waxy layer
chlorenchyma
tissue composed of thin walled parenchyma cells congaing abundant chloroplats
palisade parenchyma
layer of evenly spaced cylindrical cells whose long axes are at right angle to the upper epidermis
spongy parenchyma
makes up the lower portion of mesophyll, irregularly shaped cells with large air spaces
stomata
large air spaces in parenchyma allow for rapid easy flow of co2 and o2 and water vapour, occur all over the lower epidermis and control the passage of gases
veins
cylindrical strands of vascular tissue and occur mainly in the mesophyll
xylem cells
in vein are thick, red stained walls and absence of cell contents, they bring water into mesophyll
phloem cells
much less distinct they ar ethin walled, smaller diameter
bundle sheath cells
ring of large parenchyma cells that encircle and may radiate out from the veins
sclerenchyma
in large veins, they are part of the sheath
guard cells
sausage shaped cells that control the passage of gases in and out of the leaf
compact mesophyll
grass crops, weeds maximizes conduction betweent he cells and also minimizes any possiblilty if drying , found in high effiecency leaves
big sheath cells
round veins actively accumulate starch in specialized chloroplats
bulliform cells
bubble like cells , that have thin walls and occur in the epidermis, in hot weather, they lose water and they shrivel causing the leaf to roll or fold up
xeromorphic leaf
desgined so that its water losses are minimized, they are plants that grow in dry places or in desert
they have thick cuticle, sunken stomata, epdiermal cells with thick walls
hydromorphic leaf
found in plants that grow either in submered in water of with their roots continually in wet soil and their leaves floating on the surface
high efficiency leaf
more compact mesophyll of the leaves of these grass crops maximizes conduction between cthe cells and also minimizes any possibilities of drying
- numerous veins provide each cell with more direct access two water
- big sheath cells around veins actively accumulate starch in specialized chloroplats and their close contact wtih eveins aids in rapid removal of the photosynthate and this results in higher rates of photosynthesis, which results in greater yield and more vigorous growth
- also have bulliform cells, which when very hot, water losses from leaf are high, these cells lose water, and as a result they shrivel causing the leaf to roll or fold up
