Question

b ory Marvel Observation Flowering Plant Life Cycle Use Figure 10.6 as a guide to describe the life cycle of flowering plants 1. The parts of the flower involved in reproduction are the and the 2. The there the top of the same has two sacs, which produce - by meiosis. 3. Within an ovule, a megaspore mother sellepoes meliosis to produce four three of which die 4. A microspore underpoes mitosis and becomes a - the male gametophyte. 5. One megaspore undergoes mitosis and develops into an) which contains, in addition to other cells, two -nuclel and the cell (These terms are shaded.) 6. Pollination is the transport of pollen by wind hy animals such as insects (see Fig. 10.1) from the pollen sacs to the stigmas of carpels. After a pollen grain leads on the sigma of a carpel, it develops a pollen tube that passes down the style and takes sperm to the embryo sac. 7. During double fertilization, one sperm from the pollen tube fertilizes the cre within the embryo sac, and the other joins with the two nuclei & The fertilized egg becomes an and the joining of polar nuclei and sperm becomes the triploid (3n) endosperm. The ovule wall becomes the seed COM A seed contains a sporophyte embryo, stored food, and a seed coat. In angiosperms, seeds are enclosed by (not shown) A fruit assists in the dispersal of seeds (e.., when animals at fleshy fruits, they may ingest the seeds and disperse them by defecation sometime later) 9. After dispersal of the seed, it germinates and beins to grow, eventually becoming an adult sporophyte that bears flowers 10.3 Pollination and Development of the Embryo Pollination, the movement of pollen from the pollen sacs to the stigmas of carpels, is an important event in flowering plants. In some plants, wind accomplishes pollination and these plants produce copious amounts of pollen (Fig. 10.7). Why would you expect wind to carry out pollination for a tree and not for a garden plant? - Figure 10.7 Wind pollination of a grass, with SEM of pollen grains. ng pulled Tin Olyam Laboratory 10 Reproduction in Flowering Plants 125

Answer 1

1. The stamens and pistil are the part of the flower which involves in the reproduction. Stamens are the male reproductive organ and the pistil are the Female Reproductive Organ

2. The anther is attached to the filament. There is two sac in each anther lob called pollen sac (microsporangia). Pollen grains are produced from pollen sac through meiosis

3. The megaspore mother cell divides by meiosis to produce four haploid megaspores. Out of four, three of these megaspores degenerate, only one megaspore is functional and forms the mega gametophyte.

4. The microspore undergo mitotic division to form pollen grain. It is otherwise known as male gametophyte.

5. The nucleus of the functional megaspore divides mitotically to form a female gametophyte which is eight nucleated. It contains two polar nucleus and one egg cell. Three cells are grouped together at the micropylar end and constitute the egg apparatus. The egg apparatus, in turn, consists of two synergids and one egg cell. Three cells are at the chalazal end and are called the antipodals.

6. Pollen tube release two sperm cells in to embryo sac.

7. The one male gamete moves towards the two polar nuclei and fuses with it to produce a triploid primary endosperm nucleus

8. The fertilised egg become zygote. In angiosperms the seeds are enclosed in the ovary