Double Fertilisation

Assertion : In angiosperms, endosperm development precedes embryo development. Reason : Double fertilisation ensures that the nutritive tissue is formed before the zygotes starts cleaving so that the energy spent on the formation of endosperm does not get wasted.

Read the following statements, state true (T) or false (F) for them and select the correct option. (a) Cleistogamous flowers prevent geitonogamy as well as xenogamy. (b) Double fertilisation occurs in all spermatophytes. (c) In pea family, the single cotyledon is called scutellum. (d) Seeds of castor and coconut retain a part of endosperm during embryo development.

(a) Draw the longitudinal section of a flower showing growth of pollen tube upto the embryo sac.Label the following parts : (i) Stigma (ii) Pollen tube (iii) Integument (iv) Chalazal end (v) Nucelllus (vi) Synergids (b) What is double fertilisation in Angiosperms? Why is it so called ?

How does fertilisation take place? Fertilisation occurs once in a month. Comment.

In Pinus the fertilisation takes place in the

Define the following: Fertilisation

Carbon dioxides fertilisation effect is

Development of fruit without fertilisation is

Although in most of species fruits are result of fertilisation, there are a few species in which fruit develop without fertilisation - process is known as:

Differentiate between : Fertilisation and Parturition