stoma (English) [ IPA: ˈstoʊmə ASM: ষ্ট’মা]
Contributed by: Pankaj Borah (পঙ্কজ বৰা) on 2008-11-12
1. (Common Noun-Common) In botany, a stoma (also stomate; plural stomata) is a pore or valve, found in the leaf and stem epidermis that is used for gas exchange. The pore is formed by a pair of specialized parenchyma cells known as guard cells which are responsible for regulating the size of the opening. Air containing carbon dioxide enters the plant through these openings where it is used in photosynthesis and respiration. Oxygen produced by photosynthesis in the spongy layer cells (parenchyma cells with pectin) of the leaf interior exits through these same openings. Also, water vapor is released into the atmosphere through these pores in a process called transpiration. গছৰ পাতৰ পৃষ্ঠত থকা বিশেষ কিছু ৰন্ধ্ৰ বা ফুটা যাৰ মাজেদি গেছ আৰু জলীয় বাষ্পৰ আদান-প্ৰদান হয় |