Question

Double fertilization and triple fusion are characteristics of 

A. Spermatophyta

B. Gymnosperms

C. Pteridophyta

D. Angiosperms

Answer 1

Hint: Double fertilization is the characteristics of the most advanced and evolved species of plants. Flower formation, seeds, and covered ovules are unique features seen in these plants. They are also known as flowering plants or Magnoliophyta.

Complete answer:

Double fertilization which consists of syngamy and triple fusion is a characteristic feature of only angiosperms and not observed in any other division of the plant kingdom. The triple fusion includes the fusion of a sperm with an egg cell to form the zygote, which is followed by the fusion of two more sperms with the polar nuclei that give rise to endosperm. 

Additional Information:

The events taking place in double fertilization are described below:

> The pollen tube after germination enters through one of the synergids with the help of a filiform apparatus and releases two male gametes within the embryo sac.

> One of the male gametes fuses with the egg cell to form a diploid zygote.

> The remaining mail gametes out of the two fuses with the diploid secondary nucleus and forms a triploid endosperm nucleus.

> Because two types of fertilization are taking place at the same time this is known as double fertilization.

> It was observed for the first time by S.G. Nawaschin plants are named Lilium and Fritillaria.

Let us understand the significance of double fertilization:

> The seeds formed as the end product are more viable and chances of survival are high.

> The endosperm formed serves as a source of nutrition to the embryo without which it can not develop.

> Ovary gets transformed into fruit after fertilization occurs.

> The ploidy of chromosomes in the offspring is maintained.

So, the correct answer is, “double fertilization and triple fusion are characteristics of angiosperms.”

Note: Out of the two fertilizations that take place during double fertilization, syngamy is known as true fertilization because the actual embryo formation occurs due to syngamy. The ploidy of each egg cell and male gametes is haploid. The triple fusion is known as vegetative fertilization as it results in the formation of the endosperm. It is to be remembered that the embryo is triploid, due to the fusion of two haploid central nuclei known as secondary nuclei and one haploid male gamete. The endosperm provides nourishment to both embryo and seedling.