question_answer

What helps in flowering?

A)  Cytochrome   

B)  ABA

C)  Phytochrome  

D)  Ethylene

Correct Answer: C

Solution :

Phytochrome is an amorphous photoreceptor protein pigment. It exists in two states i.e., phytochrome Red \[({{P}_{r}})\]  and phytochrome far-red \[({{P}_{r}})\] . It is considered that during ihe day Pfr form of the phytochrome is accumulated in the plant  which is inhibitory co flowering in short-day plants but is stirnulatory in long day plants., Ethylene is a gaseous hormone and cause the ripening of climacto.nc fruits. It stimulates flowering in pinear.ple and other related plants. Abscisic acid (ABA) is a acidic growth hormone which functions as a general growth inhibitor by counteracting other hormones (auxin, gibberellin, cytokinin) or reaction mediated by them. Athough in small quantity ABA is known to promote flowering in some short day plants. Cytochromes are proteins with characteristic strong absorption fo visible light due to their iron-containing haem prosthatic groups. The cytochromes play important role as electron carrier in oxidative and photo-phosphorylation.