Important Questions for Class 12 Chapter 2 - Sexual Reproduction in Flowering Plants

Biology is a tough subject. Do you think so? It is a very common notion among students to think that science is tough. However, with the right kind of attention and preparation, you can achieve good scores in science every time. Whether you are preparing for the final board exam or any competitive exam, all you need to do is practice. Download now!

Important questions based on NCERT syllabus for Chapter 2 - Sexual Reproduction in Flowering Plants:

Question-1: What is meant by monosporic development of female gametophyte?

Solution: In many flowering plants, only one out of the four megaspores enlarges and develops into female gametophyte or embryo sac. The other three megaspores degenerate. This type of embryo sac formation is called as monosporic type of development.

Question-2: What are chasmogamous flowers? Can cross-pollination occur in cleistogamous flowers? Give reasons for your answer.

Solution: Chasmogamous flowers or open flowers in which anther and stigma are exposed for pollination. Cross-pollination cannot occur in cleistogamous flowers. These flowers remain closed thus causing only self-pollination. In cleistogamous flowers, anthers dehisce inside the closed flowers. So the pollen grains come in contact with stigma. Thus there is no chance of cross¬pollination, e.g., Oxalis, Viola.

Question-3: Mention two strategies evolved to prevent self-pollination in flowers.

Solution: Continued self-pollination decreases the vigour and vitality of a particular race. Thus, flowering plants have developed many devices to discourage self-pollination and to encourage cross-pollination.
Dichogamy and self-sterility are.two most common devices that ensure cross-pollination. Dichogamy – Maturation of anther and stigma at different times in a bisexual flower prevent self-pollination.
Self-sterility (or self-incompatibility) – Due to the presence of self-sterile gene in some flowers, pollen grains do not germinate on the stigma of that flowers. e.g.,- tobacco, potato.