Plant tissues Flashcards
(17 cards)
What does xylem consist of
vessels and tracheids
functions of xylem
transport water and minerals
What does pholem consist of
consists of sieve tubes and companion cells
Functions of Pholem
transport of food from leaves to the rest of the plant
Root epidermals ?
cells that absorb water from the soil
Adaptions for absorption
root hairs give a large surface area lower H2O concentration than soil H2O
root pressure
the force due to the intake of H2O that pushes water up the xylem
transpiration
the loss of water vapour in a plant
cohesion
water molecules are attracted to eachother
adhesion
water molecules attracted to walls of xylem
dixon and joly cohesion - tension model of xyle transport
when water vaporates from leaves water is pulled out of xylem to replace it tension the arises in the water column and water is pulled up in xylem cohesion keeps water molecules together an unbroke colomn of water moves from roots to the top of the plant
Minerals
minerals dissolved in water by root epidermal cells by diffusion they are transported in the xylem vessels to all parts of the plant
CO2
carbon dioxide is produced in plant respiration and diffuses in the air through the stomata carbon dioxide then moves within the plant by diffusion through air spaces
photosynthetic products carbohydrate oxygen
the carbohydrate produced in leaves in photosynthesis is transported in pholem sieve tube cells to other parts of the plant . carbohydrate in stored as a starch . oxygen may be used in plant respiration or it may diffuse via the stomata
Modified plant food storage organs
modified root - tap root- carrot
modified stem - stem tuber - potato
modified leaf - bulb - onion
adaptions in leaf for gas exchange
large number of stomata - large surface area and air spaces
stomata
opens in the epidermis of leaves for gas exchange
guard cells control opening and closing
affected by the level of carbon dioxide in the leaf
