Practice question

Flower formation arises when shoot apical meristem transitions to floral meristem under florigen FT protein action, internodes become strongly condensed bringing nodes bearing bracts, sepals, petals, stamens and carpels close together onto thalamus. Evidence includes leafy sepals in homeotic mutants, vascular traces and phyllotaxy shifting from spiral to whorled. Roots produce lateral roots not flowers, axillary buds generate vegetative branches whereas floral evocation involves LEAFY APETALA1 gene expression. Condensation of internodes allows compact arrangement for pollinator attraction, protection of ovules and synchronous development of floral whorls characteristic of angiosperms.