This is a genetic mechanism that prevents self-pollination by inhibiting pollen germination or pollen tube growth in the pistil,thereby preventing fertilization.

Self-incompatibility is a device for
$I$. Ensuring cross-pollination
$II$. Preventing self-pollination
$III$. Ensuring self-fertilisation
$IV$. Genetic control for self-fertilisation
Choose the correct statements from those given above.

In some plants,stigma and anther mature at different times because

Given below are two statements.
Statement $I$: Self-incompatibility is a device that prevents outbreeding.
Statement $II$: Self-incompatibility is a genetic mechanism due to which germination of pollen on the stigma of the same flower is inhibited.
In the light of the above two statements,choose the correct answer from the options given below.

When the pollen grains are not transferred from anthers to the stigma in a flower due to a physical barrier or fence,or when some natural barrier exists between the androecium and gynoecium to check self-pollination,it is known as:

Dichogamy,which helps in cross-pollination,is a floral mechanism in which: