Transport in plants

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Transport in plants

plants vascular system is made up of xylem tissue and pholem tissue. 

xylem vessels

long tube like structures joined end together with no end walls. they are dead so have no cytoplasm they are thickened with lignin which stops them collapsing inwards, it is deposited in different ways which gives rise to flexiblity (it increases with age), water and minerals move out the xylem via pits in the walls where there is no lignin

pholem tissue- contains sieve tube elements and companion cells

sieve tube elements

living cells joined end to end, the end walls are sieve plates that have holes in to allow solutes through. they have no nuclues, very thin layer of cytoplasm and few organelles. thecytoplasm of adjacent cells in connected through the sieve plates.

companion cells

carry out living functions for themselves and the sieve elements. 

root                                                    stem

(http://sci.waikato.ac.nz/farm/images/dicot%20root%20stele_labelled_web.png) (http://sci.waikato.ac.nz/farm/images/dicot%20stem_labelled_web.png)

leaf

 

Dissection

1) use a scalpel to cut a cross section

2) place in water using tweezers to stop them drying

3) add drop of water and plant section and stain and put on cover slip

water transport

water travels through root via the;

symplast pathway-goes through living parts of cells,cytoplasm which connects to neighbouring cells via plasmodesmata water moves by osmosis

apoplast pathway-goes through nonliving parts,cell wall, water can just diffuse through them and the space between them and water can carry solutes from areas of high hydrostatic pressure to low hydrostatic pressure, this is mass movement. when wtaer gets to the endodermis the root is blocked by a waxy strip called the casparian strip, so…

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