BIOLOGY A LEVEL REVISION NOTES / DIAGRAMS

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EOULRPLANT
REMOVED AUXINPASTE AUXIN INHIBITOR

APEX REMOVED RING OF AUXIN




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TRANSPORT
INHIBITOR
SIDE
BRANCHES




Suggests auxins in the apical Lack of lateral Lateral bud
growth further growth proves
bud prevents lateral buds from hypothesis that normal auxin
dominance where auxin inhibits suggest auxin is responsible -




growing when the tip is removed, but exposure to O2 could have
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level in lateral buds inhibits
lateral growth but promotes auxin levels in the shoot drop produced a hormone responsible growth whereas low auxin levels
vertical growth. and the buds grow . growth
.
I



RICE PLANTS PEA PLANTS SEED GERMINATION

DWARF PEA TALL H20




· u .
PEAPLANT




⑭
Fi
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Fi Fi
The Japanese Gibberella fujikuroi Taller pea plants have
fungus ,
,
causes disease
higher GA , (another type The
gibberellin enables the
in rice plants causing them to grow very tall. This is
of gibberellin) levels whereas in awarf varieties it is production of amylase which
Secretes a type of gibberellin lower GA , is found to be
directly responsible for breaks down starch to glucose This
fungus
.




because the .




to be used for
called acid (GAs) , which can be used to
stem elongation . allows glucose
gibberellic GAzo which so the seed embryo can
taller GA , formed from of
the conversion ,
respiration
dwarf varieties of plants grow is
.

make
The can also be used
responsible catalysed by an enzyme encoded by the Legene. grow . glucose
This suggests that gibberellin is is
is Calso allows
for protein synthes
for plant stem growth. for growth).