Question

Explain how leaves of mesophytes are suited to their functions.

Answer 1

1. Have broad and flat lamina to increase SA to trap maximum sunlight and take up more CO2 for photosynthesis.
2. Are thin to reduce the distance for diffusing gases i.e. CO2 and O2 and also for maximum penetration of light to photosynthetic cells.
3. Have palisade cells which contain numerous chloroplast, especially on upper epidermis for maximum light absorption directly from the sun; palisades are also closely packed together with long axis and located beneath the upper epidermis to receive maximum sunlight.
4. Have veins that contain vascular tissue i.e. xylem and phloem xylem conduct water and minerals salts from the soil to the leaves/ photosynthetic tissue/cells while phloem translocates soluble products of photosynthesis from the leaves to growing regions.
5. Have stomata which allow diffusion of gases CO2 and O2 and also allow transpiration to take place.
6. Have guard cells that control opening and closing of stomata hence regulates exchange of gases and water loss.
7. Cuticle and epidermis are transparent to allow easier penetration of light to palisade cells.
8. The spongy mesophyll contains cells that are loosely packed or have large air spaces to allow easier circulation of gases and diffusion of gases in and out of palisade cells.
9. Epidermis is thin i.e. one cell thick to reduce the distance for diffusing gases and ensure penetration of light to photosynthetic cells.