Plant Reproductive Biology Quiz

Anther Structure

• An anther is a four-sided (tetragonal) structure consisting of four microsporangia located at the corners, two in each lobe.
• Each microsporangium develops into a pollen sac, extending longitudinally throughout the length of the anther and packed with pollen grains.

Microsporangium Structure

• A microsporangium appears near circular in outline in a transverse section.
• It is surrounded by four wall layers: epidermis, endothecium, middle layers, and the tapetum.
• The outer three wall layers perform the function of protection and help in dehiscence of anther to release the pollen.
• The innermost wall layer is the tapetum, which nourishes the developing pollen grains.
• Tapetal cells possess dense cytoplasm and generally have more than one nucleus.

Microsporogenesis

• The cells of the sporogenous tissue undergo meiotic divisions to form microspore tetrads.
• The ploidy of the cells of the tetrad is haploid.

Reproductive Structures

• The androecium represents the male reproductive organ, consisting of a whorl of stamens.
• Each stamen consists of a filament and a terminal, generally bilobed, anther.
• The proximal end of the filament is attached to the thalamus or petal of the flower.
• The number and length of stamens are variable in flowers of different species.

Anther Variation

• Typical angiosperm anthers are bilobed, with each lobe having two theca (dithecous).
• A longitudinal groove often runs lengthwise, separating the theca.
• There is a large variation in size, shape, and attachment of anthers in different flowers.