1.

Explain the four parts of flower.

Answer»

Flower has four parts :

Calyx and Corolla - Accessory parts

Androecium and Gynoecium - Reproductive parts.

  • Androecium is male part and one unit is stamen.
  • Gynoecium is female part and one unit is carpel and has ovules. 
  • Ovule bears embryo sac. 
  • Embryo sac is seven celled and has 8 nucleus - 
  • Reproduction by vegetative and sexual methods.
  • In sexual reproduction pollens shed off and reach to stigma of Gynoecium by pollination.
  • Pollen germinates to form pollen tube with two male gametes and one tube nucleus.
  • One gamete fuses with egg (Syngamy) and other with secondary nucleus to form PEN (primary endosperm nucleus). The whole process is called Double fertilization.
  • Zygote forms embryo and PEN forms Endosperm in ovule which changes into seed inside fruit.
  • Ovary wall changes into Pericarp (fruit wall).
  • Alternation of generation occurs.


Discussion

No Comment Found