Question

2. Describe how each of the below cell types contributes to the principle function of the leaf (i.e. gas exchange and light absorption).

a. epidermal cells

b. guard cells

c. palisade mesophyll

d. spongy mesophyll

3. What are the functions of:

a. sepals?

b. petals?

c. stamens?

d. pistil?

e. vascular tissue (veins)

Pollination and seed dispersal

1. Give at least two examples of flower adaptations that ensure pollination.

a.

b.

2. Name three different examples of adaptations that ensure that seeds (fruit) are dispersed from the parent plant.

a.

b.

c.

3. Name a way that the parent plant helps the embryo once it has germinated. (Where do the nutrients come from that the embryo uses until it starts photosynthesizing?)

Answer 1

2.

a. epidermal cels are flat and transparent, allowing light to enter in to the leaf. Epidermis also has stomata (pores) which help in gas exchange.

b.Guard cells are present around the stomata. When the guard cells swell , they leave agap forming the pore called stoma which helps in absorbing the air in to the leaf.

c.Pallisade mesophyll is columnar cells and tightly packed, rich in chloroplasts. They are near to upper epidermis.When light falls on them, they trap sunight for photosynthesis.

d. Spongy mesophyll enclose number of air spaces, allowing the CO2 to reach the palisade cells which qare near the upper epidermis and receive light.

3.

a. Function o sepals is to protect the flower when it is in bud state.

b. Petals are brightly colored and help in attracting insects there by bringing pollination of the flowers.

c. Stamens produce pollen grains which have male gamete and help in reproduction.

d. Pistil has ovule inside the ovary and helps in reproduction as the ovule has female gamete.

Pollination and seed dispersal:

1. Adaptations of flower for pollination.

i) Petals of the flower are brightly colored to attract insects.

ii) Nectar secreted by flowers also helps in attracting the insects for pollination.

2.Examples of adaptations in seeds..

i) Wings present in Moringa help them to be light , so that they can be carried by wind.

ii) The cotton seed is surrounded by number of cotton fibers to make it light, so that it can be carried to far off places.

iii) Coconut fruit has lot of fiber surrounding its seed. This also helps it be light . It is carried floating in the water.

3. The seed has lot of food stored in its endosperm. Endosperm is a part of the seed containing food stored by the parent plant. This food is utilized by the growing embryo till it starts photosynthesizing.