External leaf structure
The stalk of the leaf is called the Petiole.
The leaf blade contains veins and helps to form the structural framework of the leaf. It has a large vein called midrib from which all other veins are extended.
Edges of the leaves are called as Margins and they help in the plant identification.
Internal leaf structure
The skin of the leaf is called as Epidermis and it contains single layer of cells. Epidermis helps the leaf to protect them from losing lot of moisture. The epidermis also protects the small pores present on the underside of the leaf.
Leaves have stomata on their underside. Stomata are nothing but small (pores) that help the plants to breathe. These stomata take in carbon di oxide and give out oxygen for the living to breathe.
The coloring matter of the plant is called as Chloroplasts. Chloroplasts contain chlorophyll which color to the leaves. Chloroplasts are found inside the food cells.
Leaves manufacture food for the plants. The process of preparing food with the help of sunlight and chlorophyll is called as Photosynthesis. Photosynthesis is the process by which carbon di oxide and water in the presence of sunlight and chlorophyll is converted into sugar and oxygen.
Food produced in the plant move down to the roots through the stems. Food is stored in the stem, root and the leaf in the form of sugar and starch.
Plants respire with the help of Stomata present underside of the plants. Plants respire 24 hours a day.