Question

Who discovered double fertilization?
A. Emerson
B. Strasburger
C. Nawaschin
D. None of the above

Answer 1

Hint: It is a complex fertilization mechanism seen only in flowering plants, that is, angiosperms. It consists of two events, namely, syngamy and triple fusion. It was discovered in 1898.

Complete answer:
The process of double fertilization was discovered by Nawaschin. He experimented on the flowers of Fritillaria and Lilium.
According to him, this process of fertilization starts when a pollen grain adheres to the stigma of the carpel, that is, the female reproductive structure of a flower. The pollen grain then absorbs moisture and begins to germinate, forming a pollen tube that extends down reaching the ovary through the style. The tip of the pollen tube then enters the ovary and penetrates inside through the micropyle opening in the ovule. The pollen tube releases two sperm in the megagametophyte.
The total cells of an unfertilized ovule (megagametophyte) are 8 in number and are arranged in the form of 3+2+3 i.e. 3 antipodal cells, 2 polar central cells, 2 synergids, and 1 egg cell. The haploid sperm and the haploid egg combines and forms a diploid zygote, this process is called syngamy. While the other sperm and the two haploid polar nuclei of the large central cell form a triploid nucleus and are called triple fusion. The large cell of the gametophyte will then develop into the endosperm which is a nutrient-rich tissue and provides nourishment to the developing embryo. The ovary, surrounding the ovules, later develops into the fruit, which protects the seeds.
So, the correct answer is ‘Nawaschin’.

Note: The major significance of double fertilization are as follows-
-There are chances of polyembryony, and thus the plant has better chances of survival.
-Double fertilization gives rise to an endosperm that provides nourishment to the developing embryo.
-It increases the viability of the seeds in angiosperm.
-It utilizes both the male gametes produced in the pollen grains.