Question

What is double fertilization.....? define it with drawing... (full marks 5)

Answer 1

Double fertilization is a complex fertilization mechanism of flowering plants (angiosperms). This process involves the joining of a female gametophyte (megagametophyte, also called the embryo sac) with two male gametes (sperm). It begins when a pollen grain adheres to the stigma of the carpel, the female reproductive structure of a flower. The pollen grain then takes in moisture and begins to germinate, forming a pollen tube that extends down toward the ovary through the style. The tip of the pollen tube then enters the ovary and penetrates through the micropyle opening in the ovule. The pollen tube proceeds to release the two sperm in the megagametophyte.

Answer 2

Dear Student,

◆ Double fertilization -

• In angiosperms, one sperm cell fertilizes egg cell to form a zygote (2n) and one sperm cell combines with polar nuclei to form endosperm (3n). This is called double fertilization.

# Significance of double fertilization -

• Endosperm develops only if ovum is fertilized.
• Endosperm gives nourishment to the developing embryo.
• It results in rapid multiplication of plants.

Thanks dear. Hope this helps you...