plant transport Flashcards
how is the xylem and phloem structured in the root cortex?
xylem is central and star-shaped with phloem between groups of xylem cells.
why is the xylem and phloem structured this way in the root cortex?
it resists vertical stresses and anchors the plant in the soil
how is the xylem and phloem structured in the stems?
the vascular bundles are in a ring at the periphery, with xylem towards the centre and phloem towards the outside.
why is the stems structured in this way?
to give flexible support and resist bending
where is the vascular tissue in the leaves?
in the midrib to give flexible strength and resistance to tearing
what is the function of the xylem?
transporting water and minerals and providing mechanical strength and support
what is the structure of the xylem?
- xylem vessels
- tracheid
- xylem parenchyma
- fibres
what are the walls of the xylem vessels and trachea made up of?
lignin (dead cells) which is impermeable to water
how does water leave and enter the xylem?
pits in the walls
