plant tissues

Created by

matilda bailey

Cards (10)

plant tissues 
epidermal tissues
palisade mesophyll
spongy mesophyll
xylem and phloem
meristem tissue
how is the palisade mesophyll adapted to absorb light?
packed with many chloroplasts
are column shaped and closely together
towards the surface of the leaf
how is the spongy mesophyll adapted for gas exchange?
packed loosely
covered in a thin layer of water so that gases dissolve and move in and out of cells
stomata - gases diffuse through these pores, water is lost by transpiration. closing stomata controls water loss
what is the xylem?
xylem transports water and mineral from the roots up the plant stem and into the leaves - physical process
made up of vessels which lose their end walls so the xylem is a continuous hollow tube
strengthened by a chemical called lignin which gives strength and support to the plant
what is the phloem?
moves food substances where they are needed for growth, seed development and storage.
transports both top and down the stem and requires energy - translocation
what are sieve tubes?
tubes in the phloem specialised for transport and have no nuclei
perforated end - cytoplasm connects cells to each other
dependent on companion cells
what is transpiration? 
caused by the evaporation and diffusion of water from a plants surface
evaporation creates a shortage of water in the leaf os more water is drawn up by xylem vessels to replace it
more water is drawn up through the roots so there is a constant transpiration stream through the plant.
factors affecting rate of transpiration?
light intensity - the brighter the light, the greater the rate of transpiration
temperature - the warmer it is, the faster the rate of transpiration
air flow - the better the air flow, the greater the transpiration
humidity - the drier it is, the faster transpiration happens
a potometer measures the rate of transpiration by measuring the uptake of water by a plant.
what are guard cells?