Anthers are removed before they dehisce from the flower of the female plant if it is bisexual. This step is referred to as emasculation. There is no need to remove the anthers if the flower is unisexual. The flowers are then covered with a bag of suitable size, generally made up of butter paper, to prevent contamination of its stigma with unwanted pollen. This process is called bagging.
Advantages of bagging technique
1. It is necessary for cross-breeding and to prevent pollination by unwanted species in plant breeding.
2. Commercially superior hybrid varieties can be obtained by cross pollination of different useful species.
3. It helps to avoid inbreeding depression caused by self pollination.
(a) hypocotyl and epicotyl
(b) Coleoptile and coleorhiza
(c) Integument and testa
(d) Perisperm and pericarp.
With a neat labelled diagram, describe the parts of a typical angiosperm ovule.
What is self-incompatibility? Why does self-pollination not lead to seed formation in self-incompatible species?
Name the parts of an angiosperm flower in which development of male and female gametophyte take place.
(a) Draw a diagrammatic sectional view of a mature anatropous ovule and label the following parts in it:
(i) that develops into seed coat.
(ii) that develops into an embryo after fertilization.
(iii) that develops into an endosperm in an albuminous seed.
(iv) through which the pollen tube grains entry into the embryo sac.
(v) that attaches the ovule to the placenta.
(b) Describe the characteristic features of wind pollinated flowers.(a) Explain the different ways apomictic seeds can develop. Give an example of each.
(b) Mention one advantage of apomictic seeds to farmers.
(c) Draw a labelled mature stage of a dicotyledonous embryo.(a) Explain the post-pollination events leading to seed production in angiosperms.
(b) List the different types of pollination depending upon the source of pollen grains.