Question

Double fertilization involves
A. Fertilization of the egg by two male gametes
B. Fertilization of two eggs in the same embryo sac by two sperms brought by one pollen tube
C. Fertilization of egg and the central cell by two sperms brought by different pollen tubes
D. Fertilization of egg and the central cell by two sperms brought by the same pollen tube

Answer 1

Hint:-Double fertilization is a type of fertilization which is complex in nature which takes place in flowering plants that are angiosperms. It basically means when the fertilization takes place of egg and the central cell by two sperms by the same pollen tube.

Complete answer:
Double fertilization occurs in angiosperms in which pollen grain sticks to the stigma of the carpel, which is the female reproductive structure of a flower, then pollen grain takes in moisture and germinates which forms the pollen tube which moves downwards towards the ovary through style. The pollen tube proceeds to release the two sperm in the megagametophyte. It can be generally studied by the simple definition which states that when male gamete fuses with female gamete and the secondary nucleus, respectively. In this we need to understand that one male gamete that fuses with a female gamete and forms the zygote (2n) develops into seed. The second male gamete in double fertilization fuses with the secondary nucleus of the central cell and this forms the triploid primary endosperm nucleus (3n). Now this is known as triple fusion. Some plants may form polyploid nuclei. The ovary develops into fruit which protects the seed and can also function to disperse them.
The primary endosperm later gives rise to the endosperm. It provides nutrition and nourishment to the developing embryo.
Thus, the right option is D.

Note:- Double fertilization was discovered by “Sergei Nawaschin and Grignard”. Both of them made discoveries independently. The female gametophytes can also be called as ‘Megagametophytes’ whereas male gametophytes are called as ‘ Microgametophytes’.