Intraspecific incompatability can be overcome by

Insect-pollinated flowers are characterized by

An ovule which becomes curved so that the nucellus and embryo sac lie at right angles to the funicle is

In some plants anthers and stigma grow and mature at the same time.This phenomenon is called

Identify the wrong statement regarding post-fertilization development

Explain any two ways by wich apomictic seeds get developed.

How do plants produce seeds through apomixis? Explain with the help of an example.

Why is it necessary to emasculate a bisexual flower in a plant breeding programme? Mention the condition under which emasculation is not necessary.

Mention the location and function of tapetum in the microsporangium of angiosperms. State the characteristic features of the cells forming this layer.

Write the mode of pollination in Vallisneria and water lily. explain the mechanism of pollination in Vallisneria. 

Differentiate between perisperm and endosperm, giving one example of each.

What is triple fusion? Where and how does it take place? Name the nuclei involved in triple fusion.

(a) Identify the figure. 
(b) Name the initial cell from which this structure has developed.
(c) Draw the next mature stage and label the parts.

Explain double fertilisation and trace the post-fertilisation events in sequential order leading to seed formation in a typical dicotyledonous plant.

Explain the development of the zygote into an embryo and of the primary endosperm nucleus into an endosperm in a fertilised embryo sac of a dicot plant. 

(a) Describe the process of mega-sporogenesis in angiosperms, until 8-nucleate stage.
(b) Draw the labelled structure of mature embryo sac.

Explain with help of a diagram, the development of a mature embryo sac from a megaspore mother cell in an angiosperm.