The stomata
The stomata of plants are a cellular type that allow the gaseous exchange of the leaves of the terrestrial plants. Stomas are a structure that is formed by two cells found in the epidermis of the green tissues of plants, especially on the surface of the leaves, both in the bundle and in the back, being more frequent on the underside. Plants adapted to droughts and severe sunstrokes usually have fewer stomata in general and these are located much more often on the underside of the leaf to reduce the loss of water by perspiration. In this way stomata are protected from the sun and allows better control of perspiration (loss of water), so stomata can exchange gases without danger of dehydration.
In low water conditions the stomata are closed to avoid dehydration. On the other hand, when there is a low concentration of CO2 in the leaf mesophyll, the accompanying cells activate the opening of the stoma to capture CO2. When it is sunny and the plant has water, it opens the stomata to exchange gases. At night the stomata are closed since chloroplasts are not working.
The lenticels
They are small openings in the stem of the plants. It is found in young branches, in roots they can be arranged in pairs, one on each side of the lateral roots. Also in some fruits like the apple and the avocado.
In the smooth barks like the one of Rapanea Oxygen enters through lenticels because it is necessary for the cellular respiration. The entry of carbon dioxide into the lenticels is not important, as the photosynthesis is not carried out on the stem. The lenticels allow the interchange of gases between the metabolically active interior tissue and the surrounding air or pockets of air in the soil.
Origin . In peridermis initiated in subepidermal layers, the first lenticels frequently form below the stomata. The parenchyma cells surrounding the sub-static chamber are actively divided and form the lenticella felogen, which produces felodermis inward and outward filling cells. The latter accumulate in quantity, break the epidermis and protrude outwards.
Lenticels are often formed before the development of the peridermis, as in the stems of Aristolochia and Menispermum .
Main difference between stomata and lenticels
- Stomata is located in the epidermis lenticels are located in peridermis
- Lenticels are always opening Stomata regulates its own opening when required .
- Lenticels are formed after secondary growth of the plant while stomata are found in the primary growth of the plant
- Stomata have guard cells while Lenticels do not have guard cells
- Stomata are mostly found on the underside of a leaf while lenticels are found on the stems region eg barks of trees
- Stomata the guard cell has chloroplast ,the lenticels have no chloroplast
