Question

Photosynthesis in green plants is directly and indirectly dependent on so many plant structures. Explain briefly the role of the following structures in this process.
(a) Guard cells ..............................................
(b) Cuticle.......................................................................
(c) Mesophyll cells........................................................
(d) Xylem tissue in the leaf veins...............................
(e) Phloem tissue in the leaf veins..............................
(f) Stomata......................................................................

Answer 1

(a) Guard cells are cells surrounding each stoma. They help to regulate the rate of transpiration by opening and closing the stomata.
(b) Cuticle is transparent and waterproof to allow light to enter freely. It prevents entry of pathogens and loss of water due to evaporation.
(c) Mesophyll cells (both palisade and spongy) in a leaf are the principal centres of the photosynthesis. During day time, when sunlight falls on the leaf, the light energy is trapped by the chlorophyll of the upper layers of mesophyll, especially the palisade cells.
(d) The xylem consists of tracheids and vessels, which transport water and minerals to the leaves.
(e) The phloem transports the photosynthetic products from the leaf to the other parts of the plant. A single vascular bundle, no matter how large or small, always contains both xylem and phloem tissues.
(f) Stomata are minute opening occurring in large numbers on the lower surface of a leaf. The main function of the stomata is to let in $C{O}_2$ from the atmosphere for photosynthesis.