Question

What is double fertilization? Explain.

Hint:

Double fertilization = one male gamete + egg (zygote) AND another male gamete + polar nuclei (endosperm). A feature unique to angiosperms.

Answer 1

Double fertilization is a unique phenomenon that occurs in flowering plants (angiosperms). It involves the fusion of one male gamete with the egg cell and another male gamete with the secondary nucleus in the embryo sac.

Step 1: Process. \[\begin{array}{rl} 1. & \text{After pollination, the pollen tube carries two male gametes into the embryo sac.} \\ 2. & \text{One male gamete fuses with the egg cell (\(n + n = 2n\)) to form the zygote, which develops into the embryo.} \\ 3. & \text{The other male gamete fuses with the two polar nuclei (\(n + n + n = 3n\)) to form the primary endosperm nucleus (PEN), which develops into the endosperm (food storage tissue).} \\ \end{array}\]

Step 2: Significance. \[\begin{array}{rl} \bullet & \text{Ensures synchronous development of embryo and endosperm.} \\ \bullet & \text{Endosperm provides nutrition for the developing embryo.} \\ \bullet & \text{This unique feature differentiates angiosperms from other plant groups.} \\ \end{array}\]