Question

A dithecous anther consists of ___________(i)_____ microsporangia in ______(ii)____lobe.
A.(i)four (ii)two
B.(i)two (ii)four
C.(i)two (ii)one
D.(i)two (ii)zero

Answer 1

Hint: The male reproductive organ or stamen of a flowering plant has filament and anther. The filament is a long stalk that is attached to the thalamus and the petal. The anther is the fertile part of the stamen. It consists of two lobes that are separated by a deep groove in the anterior region.

Complete answer: 1.Anther is a bilobed and tetragonal structure. It is oblong and knoblike and is referred to as the fertile part of the stamen. It is dithecous because each anther lobe has two chambers or theca.
2.Long and cylindrical pollen sacs or microsporangia are present in the two chambers of an anther lobe. Hence, we can say that a bilobed anther is tetrasporangiate. The four microsporangia are located at the four corners and they are arranged parallelly to one another.
3.A shallow groove on the outside and sterile parenchyma on the inside separate the two microsporangia of an anther lobe. A well-defined common epidermis covered all the four microsporangia externally.
4.A microsporangium is a future pollen sac that is circular in shape in the transverse section. An outer wall and a central homogenous sporogenous tissue are the two parts of a microsporangium. Epidermis, endothecium, one to three middle layers, and tapetum are present in the walls of a microsporangium.
Thus, the correct option is A) (i)four (ii)two.

Note:Some important facts about anther and microsporangia are:
1.Thus, an anther is considered as the site for pollen development. The pollen grains fertilize the ovules which leads to the formation of a zygote.
2.Microspores are formed in the microsporangium and after germination, they give rise to male gametophytes.