Page 90 - Teknik Menjawab Soalan PSPM Biologi

Role of phytochromes in controlling flowering

∙ During the night, P FR ∙

spontaneously converted back to But in short day plants, high level
of P
inhibits the production of
FR
P Slowly florigen
R.
∙ Or converted rapidly to P FR

when exposed to far red light. ∙ Therefore inhibits flowering of

short day plant
∙ In long day plant, more P is
R
converted into P FR due to longer ∙ But when exposed to a short day

light exposure period of daylight,less P is
R
converted to P FR.

∙ In long day plants, high level of ∙ Low level of P stimulate the

FR
P FR stimulate the production of production of florigen hormone
florigen hormone
∙ which stimulate flowering in short

∙ which stimulate flowering in long day plants

day plants.

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