Question

b).What are the post fertilizational changes in the flower​

Answer 1

POST FERTILISATION :

• The events occuring after the fertilization of the egg and male gamete are called post fertilisation events.

• The fertilised ovule forms seed.

• The ovary transforms into fruit.

• The fertilization of egg and male gamete results in the formation of diploid zygote.

• The secondary nucleus or primary endosperm nucleus fuse with the other male gamete to form triploid endosperm. This is called triple fusion.

• Endosperm is highly nutritive tissue. It provides nutrition to the growing embryo.

• In some dicots , the endosperm is completely consumed during the development. These are called non endospermous or ex albuminous seed.

• In some monocots, the endosperm is not completely consumed. They are called endospermous or albuminous seed.

• The flower usually withers after fertilisation.

• The antipodal cells and synergids get disintegrated.

• The integuments form the seed coat.

• The zygote inside the seed divides to form embryo.

• In dicot seeds , the embryo consists of two cotyledons and an embryonal axis.

• The root tip and shoot tip of dicots are called radicle and plumule respectively.

• In monocot seeds, the embryo consists of single cotyledon called scutellum.

• The endosperm in monocot seed is covered by a proteinaceous layer called aleurone membrane.

• The radicle and plumule of monocot seeds are covered by a sheath called coleorhiza and coleoptile respectively.

• In monocots , the outer seed coat is called testa and the inner seed coat is called tegmen.

Answer 2

Answer:

Post – fertilization changes in flowers are –

a) The sepals, petals and stamens wither off

b) Style and stigma degenerate

c) Ovary develops into fruit

d) Ovules grows into seed

e) Integuments of the ovule act as seed coats.

f) Fertilized egg gets converted into embryo which bear plumule, radicle and cotyledons.

g) Fertilized polar nuclei form endosperm which may or may not be consumed during seed development.