Question

A pollen tube enters the ovule through chalaza lying opposite the micro Pyle. It will enter the embryo sac through.
(A) Chalaza end
(B) Laterally
(C) Antipodal haustorium
(D) Micropylar end

Answer 1

Hint: Micro Pyle is defined as the hole in the seed through which the water moves into the seed for the purpose of the germination. The part of the seed, before the fertilization, it is the ovule through which the pollen tube joins the ovule.

Complete answer:
Micro Pyle is located at the point of joining of both the pollen tube and the ovule. The pollen, the male gamete enters into the pollen tube follows the three routes to reach the ovule for the purpose of fertilization. These three points are porogamy, mesogamy and chalazogamy.
(1) Porogamy:
The pollen grains enter the ovule through the microPyle opening in the ovule.
(2) Mesogamy:
In this type, the pollen grains enter through the funiculus or the integuments.
(3) Chalazogamy:
In chalazogamy, the male gamete pollen enters the ovule through the chalasal tissues.
In all the above routes, the pollen grains enter the ovule. But these routes often reach the micro Pyle as the final destination. Hence a pollen grain enters the embryo sac through the micropylar end.

Hence the correct answer is option(D)Note: The example of the porogamy takes place in the angiosperms like corn, wheat, corn etc. The mesogamy takes place in pumpkin, ridge gourd and bitter gourd etc. The pollen tube carries the pollen grain from the external environment and discharges it into the ovule at the point of micro Pyle.