Which phytochrome isoform is light-labile and rapidly degraded?
A fits best: PhyA. Keep the PHYTOCHROME basics straight and PhyA stands out as the precise answer. Avoid: B) PhyB; C) PhyC; D) PhyD. Light and flowering items often hinge on which photoreceptor or day-length rule is in play.
Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.