Question

(a) As a senior biology student you have been asked to demonstrate to the students of secondary level in your school, the procedure(s) that shall ensure cross-pollination in a hermaphrodite flower. List the different steps that you would suggest and provide reasons for each one of them.

(b) Draw a diagram of a section of a megasporangium of an angiosperm and label funiculus, micropyle, embryo sac and nucellus. [5]

Answer 1

(a) The different steps for cross pollination in a hermaphrodite flower are : [3]

(i) Removal of anthers from the flower bud using a pair of forceps. It is necessary to avoid self pollination. It is referred as emasculation.

(ii) Emasculated flowers covered with a bag of suitable size to prevent contamination of its stigma called bagging.

(iii) When the stigma of bagged flower attains receptivity, mature pollen grains collected from anther of the male parent are dusted on the stigma, and the flowers are rebagged to allow the fruit to develop.

(b) [1 +1]