Question

double fertilization is not found in
cucumber, rice, pinus, mango ​

Answer 1

Double fertilization absent in Pinus.

What is double fertilization ?

We know that, the male portion present in the flower is called the androecium and the female portion found in a flower is the gynoecium.

Androecium structure : This structure has two parts, that is, a long stalk known as filament and an anther. The anther releases pollen grains which contains the male gamete.

Gynoecium structure : This structure has 3 parts - stigma, style and the ovary. The ovary contains the ovule which has the egg.

When the male gamete lands on the stigma, on suitable conditions, the gamete gets germinated and gets divided into 2 male gametes in the pollen tube.

One of those gametes fuses with the egg and forms a zygote and the other gamete fuses with the polar nuclei of the embryo sac and forms endosperm.

This is double fertilization phenomenon.

Answer 2

Double fertilization is not found in Pinus.  

Explanation:  

• A complex process of fertilization that occurs in certain angiosperms is known as double fertilization or twice fertilization.
• As per this process, the female gametophyte is also depicted as the embryo sac or the megagametophyte fuses with two numbers of male gametes.
• Here fusion between the sperms and the egg occurs twice, where one sperm fuses with the female gamete to create the zygote and the other sperm fuses with the central cell in order to create the endosperm.  

Learn more about Double fertilization:

What is double fertilization?

https://brainly.in/question/2367385

Describe the process of double fertilisation in plants.

https://brainly.in/question/2688471