Question

A flower of tomato plant following the process of sexual reproduction produces 240 viable seeds.
Answer the following questions giving reasons:
(a) What is the minimum number of pollen grains that must have been involved in the pollination of its pistil?
(b) What would have been the minimum number of ovules present in the ovary?
(c) How many megaspore mother cells were involved?
(d) What is the minimum number of microspore mother cells involved in the above case?
(e) How many male gametes were involved in this case?

Answer 1

a) The minimum number of pollen grains involved in the pollination of pistil are 240 as single pollen grain produces two male gametes. Out of these one male gamete fuses with polar nuclei to give rise to endosperm and second fuses with the egg cell to give rise to zygote and zygote ultimately gives rise to seeds. Thus 240 pollen grains produce 240 seeds.

b) Since after fertilization ovules form seeds, therefore 240 viable seeds are produced from 240 ovules.

c) 240 megaspore mother cells are involved as out of the 4 megaspores of tetrad only one becomes functional and other three degenerate.

d) The minimum number of microspore mother cells involved in this case are 60 as one microspore mother cell undergoes meiosis to produce 4 microspores.

e) 240 male gametes are involved in this case as one male gamete fuses with one female gamete to produce the zygote which develops into a seed.