OCR Biology A-Level Plant Responses(2) Summary

Phototropism :



· Positive tropism In shaded
the shoots auxin will accumulate in the areas ,
elongating
:




the stem it towards the
light
so
grows
Negative tropism
:
In the roots the high auxin illuminated side will


dengate and the root will
grow away from the
light
Geotropism :



Positive tropism Roots grow in the direction of
:



gravity
Negative tropism Shoots
grow away from gravity
:




Commercial use
of plant hormones
·




Ripening
:
Ethere is used to
ripen fruit so it can be transported whilst hard and

unripe
· Powder Auxin production
Rooting stimulates new root
:




Weed and death
Gillers
Synthetic auxin will disrupt cen metabolism cause
:




·Auxins can produce seedless fruit
Ethere can
promote fruit dropping
·




Gibberelling can
delay ripening and
ageing in fruit/make bigger fruit
·Gibberelling cal also
speed up marting
in been
brewing
Cytokinins prevents fruit ageing and control tissue
development in
Micropropogation