Class 12 NEET Biology Sexual Reproduction in Flowering Plants Questions Part 1

(a) : Depending upon position of micropyle in relation to chalaza, ovules are of 6 types in angiosperms. In amphitropous type the curvature is observed both in body of ovule and embryo sac. The embryo sac assupres horse shoe-shape. Micropyle is directed downwards. It is commonly found in families Papaveracerae, Alismaceae and Butomaceae.Circinotropous ovule is characteristic of family Cactaceae. Here the ovule is straight first but due to more growth on one side gets inverted and later becomes straight again.
Orthotropous ovule is the most primitive and of simplest type. It is also known as atropous or straight ovule.
Anatropous ovule is the most common type of ovule found in angiosperms. Here the body of the ovule gets inverted and micropyle is on lower side.