FUNCTIONS OF LEAF (LEAVES)
There are three main functions of leaf:
1. Manufacture of food: Leaves Contain chlorophyll. With the help of chlorophyll the leaves manufacture carbohydrate by a complex bio-chemical process called photosynthesis.
2. Interchange of gases: Leaves help in the interchange of oxygen and carbon dioxide for various physiological functions of the plants. The gases enter and exit through stomata.
3. Transpiration: Plants get rid of excess water by transpiration through stomata present in the leaves
4. Transport of water and minerals: Transpiration by leaves helps in the ascent asap by creating suction force in the vascular column that extends upto the root.
5. Special function: Leaves undergo modification to perform some special functions such as
(a) Leaf apex, lamina, petioles, stipules etc. undergo modification to provide support to the plant (e.g. Gloriosa, pea, Clematis).
(b) Leaves are often modified into spines for defensive purpose (e.g. Argernone maxicana).
Phyllotaxy is the arrangement of adult leaves on the stems.
Perfoliation or vernation is the arrangement of immature leaves in the bud.
The manner in which the immature leaves of a bud roll, bent or folded is called ptyxis.