|tissue introduction||meristematic tissue||ground tissue||dermal tissue||vascular tissue|
Epidermal tissue is a single layer of cells, (except in velamen,pepperomia and rubber plants) that covers the plant body
Root hairs- absorb water and the material it carries ( minerals).;they increase absorptive surface area of roots
Although single celled, they can be viewed by the eye on rapidly growing radishes
Leaf hairs (trichomes)- 1-2 cells;
important in boundary layer and in defense;
*the layer acts to hold in a layer of
humidity 'trapped' between the epidermis and the tips of the trichomes.
As water diffuses from a region of high to low density, less water will
escape from the stomata to the outside air since the air layer outside
the stomata is 'moist' due to its entrapment by the trichomes.
created by guard cells; most abundant on underside of leaves;
regulate diffusion of CO2 into the leaf for photosynthesis as well as regulate loss of water from the leaf;
Stomata respond to turgor pressure
*stomata open when K+ and
water enter, thereby increasing turgor pressure in guard cells, thus pushing
Salt glands- dump sites for the
excess salt absorbed in water from the soil; help plants adapt to life
in saline environments;
The white mangrove pictured to the right has 2 salt glands on each leaf which exude salts taken up with water.