Draw a longitudinal section of a post-pollinated pistil showing entry of pollen tube into a mature embryo sac. Label filiform apparatus, chalazal end, hilum, antipodals, male gametes and secondary nucleus.

Long Answer Questions Five mark Each QUESTIONS FROM CBSE BOARD EXAMINATIONS : (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 gains entry into the embryo sac. (v) that attaches the ovule to the placenta (b) Describe the characteristic features of wind pollinated flowers.

ADDITIONAL QUESTIONS : The diagram below shows a germinating pollen grain and a mature ovule from an insect-pollinated flower. Some parts have been labelled. Give the letter of the nucleus which fuses with a male nucleus to form each of the following : (i) The zygote (ii) The endosperm