Question : (a) Draw the longitudinal section of a flower showing growth of pollen tube upto the embryo sac.Label the following parts : (i) Stigma (ii) Pollen tube (iii) Integument (iv) Chalazal end (v) Nucelllus (vi) Synergids (b) What is double fertilisation in Angiosperms? Why is it so called ?

Question : (a) Draw the longitudinal section of a flower showing growt

1.	Question : (a) Draw the longitudinal section of a flower showing growth of pollen tube upto the embryo sac.Label the following parts : (i) Stigma (ii) Pollen tube (iii) Integument (iv) Chalazal end (v) Nucelllus (vi) Synergids (b) What is double fertilisation in Angiosperms? Why is it so called ?
Answer» Solution :(a) See Q.29, Set-II.., Outside Delhi-2014 (Comptt.) [Page-245]. (b) The SECOND male gamete MOVES TOWARDS the polar nuclei in the central cell and fuses with them the produce a triploid primary endosperm nucleous. SINCE syngamy and triple fusion occur in the embryo sec. The process is called double fertilisation.