Which is the triploid tissue in a fertilised ovule? How is the triploid condition achieved?
Fertilised embryo sac showing Primary endosperm nucleus ( $3 n$ )
$$ \text { Are pollination and fertilisation necessary in apomixis? Give reasons. } $$
Pollination and fertilisation are not necessary for apomixis. The reasons in support of this are given below
(i) Embryo sac can develop from megaspore without reduction division the egg is diploid and develops into embryo.
(ii) Embryo sac can also develop from diploid nucellus cells in which case egg is diploid that develop into embryo parthogenetically.
$$ \text { Identify the type of carpel with the help of diagrams given below } $$
(a) If a gynoecium has multiple carpels fused into a single structure, it is syncarpous. In this given diagram, the type of carpel is syncarpous (e.g., poppy).
If a gynoecium has multiple carpels in free form, it is apocarpous. In this given diagram, the type of carpel is apocarpous. (e.g., michelia)
How is pollination carried out in water plants?
(a) In many aquatic plants with emergent flowers, pollination occurs by wind and insects.
(b) In water plants if pollination occurs below the surface of water is called hypohydrophilly, e.g., Ceratophyllum.
(c) In water plants if pollination takes place over the surface of water is called epihydrophily, e.g., Vallisneria spiralis.
What is the function of the two male gametes produced by each pollen grain in angiosperms.
One male gamete unites with egg forming embryo. This process is called fertilisation or syngamy.
Another male gamete unite with two polar nuclei resulting in the formation of endosperm triple fusion.