Question

Short Answer Questions

1. What is meant by monosporic development of a female gametophytes?
2. Explain giving reasons why pollen grains can be best preserved as fossils.

3. Draw a labelled diagram of L.S. of an apple.

4. List two strategies that a Bisexual chasmogamous flower can evolve to prevent self pollination.

5. How does the study of different parts of a flower help in identifying it for wind as its pollinating agent?

6. How many haploid cells are present in a mature female gametophyte of a flowering plant? Name them.

7.Write the difference between the tender coconut water and the thick, white kernel of a mature coconut and their ploidy,

16. What is apomixis? How is the phenomenon useful to the farmer?

17. Suggest two advantages to a farmer for using apomictic seeds of hybrid varieties.​

Answer 1

Answer:

1.When the female gametophyte (embryo sac) develops from a single megaspore, it is called monosporic development.

2.Pollen grains are well-preserved as fossils because of the presence of sporopollenin. Pollen grains has a prominent two-layered wall. The hard outer layer called the exine is made up of sporopollenin which is one of the most resistant organic material known. ... No enzyme that degrades sporopollenin is so far known.

Answer 2

Answer:

1. When the female Gametophyte or embryo sac develo from a single megaspore, it is called monosporic. Usually in most of the angiosperms the megaspore mother cell divides by meiosis division to form four haploid megaspore arranged in a linear fashion. The three, situated towards microplye, degenerate and one remain functional which develops into female Gametophyte.

2. Pollen Grains can be preserved as fossils by the process of cryopreservation in this process pollen Grains are kept in liquid ammonia at (-196°C).

3. Refer NCERT BOOK.

4. Self-Incompatibility and Avoiding Syncronization.