question_answer

What do you understand by the following terms

(i) Vegetative propagation

(ii) Embryogenesis

Or

(i) Anemophily is a highly wasteful process. Justify the statement.

(ii) Apomixis commonly mimics sexual reproduction. Comment.

Answer:

(i) Vegetative propagation (vegetative reproduction) is the formation of new plants from vegetative units or propagules such as buds, tuber, rhizomes, etc. This method produces a large number of population of clones in the shortest time. It preserves purity, resistance and good qualities of a variety indefinitely.

(ii) Embryogenesis The process of development of embryo from the zygote is called embryogenesis.

During embryogenesis zygote undergoes mitotic cell division and cell differentiation. Cell division increases the number of cells in the developing embryo while cell differentiation helps to form specialised tissues and organs to form an organism.

Or

(i) Anemophily is highly wasteful as it is non-directional.

Since, the blowing air is responsible for pollination, it is pollination by chance. Pollen grains coming in contact with the stigma is a chance factor in wind pollination. To compensate for these uncertainities and associated loss of pollen grains, the flowers produce enormous amount of pollen, when compared to number of ovules available for fertilisation.

(ii) Apomixis is a mode of reproduction which does not involve formation of zygote through gametic fusion. It is a form of asexual reproduction that mimics sexual reproduction but produces seeds without fertilisation, e.g. some species of Asteraceae and grasses.

There are several methods of apomictic development in seeds. The two common ones are recurrent agamospermy and adventive embryony.