what else do zylem vessels transport
the movement of water through xylem vessels provides a mass flow system for the transport of inorganic ions.
nitrate ions are needed by plants in order to make amino acids which contain one or more nitrate atoms. plants make their own amino acids from scratch using inorganic materials. by a sequence of enzyme controlled reactions the nitrogen transported in the xylem is combined with organic molecules from photosyntheis to make all 20 amino acids. plants cannot grow without nitrate ions.
if not enough of these inorganic ions are absorbed by the plant it will show deficiency symptoms. for example if the plant lack magnesium it is unable to make chlorophyl and the old leaves become yellow. and a lack of calcium causes stnuted growth.
xylem and sclerenchyma for support
ligin not only waterproofs the cell walls, it also makes them much stiffer and gives the plant greater tensile strength.
the sclerenchya is also impregnated with lignin.
the taller the plant needs to grow the greater proportion of the plant that needs to be lignified.
a turgid cell is one that is completely full with its cell contents pressing out on the cell wall.
useful plant fibres
plant fibres can be of great use to humans as they are:
- long and thin
plant fibres can be extracted either mechanically by pulling out fibres or by digesting the surrounding tissue.
the more lignin present in the plant the hearder it is to extract the fibres.