lecture 5 Flashcards
what are the three primary meristems? what tissue system do they belong to?
protoderm (dermal), ground meristem (ground), procambium (vascular)
what is the epidermis? what are its functions?
outermost layer of cells that covers the surface of all plant organs. control what goes in and out of the plant and protects the plant from the environment
what is the epidermis usually covered with?
a waxy, hydrophobic cuticle
what are the three types of epidermal cells?
pavement cells, guard cells, trichomes
what are the functions of the cuticle?
- minimize water loss and prevent organ fusion
- surface self-cleaning
- folds and ridges prevent extended contact between different surfaces and create iridescence that attracts pollinators
what are the characteristics and functions of pavement epidermal cells?
shaped like puzzle pieces and usually have no chloroplasts. function in general protection and support
what are the functions of guard cells?
- form pores in the plant’s epidermis
- can open and close stomata by changes in turgor
- control gas exchange
what is a trichome?
a unicellular or multicellular outgrowth of the epidermis on stems, leaves, or flowers
what are the functions of trichomes?
- protection from herbivores and insects
- limit water loss from leaf/stem
- protect from high sunlight by reflecting it, which also helps cool the organ, reducing water loss
- exude chemicals for defense or attraction
what are the characteristics and functions of non-glandular/non-secretory trichomes?
often hair-like and function in physical protection
what are the characteristics of glandular/secretory trichomes?
stalked, sessile, and bulbous, and produce secretions (essential oils) and provide chemical protection
what are the two types of epidermal cells in roots? what are their functions?
- hair cells (trichoblasts): absorb water and nutrients
- non-hair cells (atrichoblasts): provide support and ensure space between hairs
what is the periderm? what is its function?
the secondary epidermis, derived from cork cambium (a secondary meristem). functions in protection and control of water loss
