Just as we have seen that roots and stems are fundamental parts of plants, it is also important to know that leaves play an elemental role in the life of these beings. By means of leaves, plants carry out photosynthesis, breathe and produce food. Respiration occurs during the day and night; to do this, plants take oxygen from the air and release carbon dioxide.
Just as human beings sweat when we are hot, plants, through their leaves, eliminate part of the water they absorb through their roots. This process is called transpiration and can be observed when we keep the leaves of a plant inside a plastic bag and see that the bag is moistened with the water exuded by the leaves. If we could see the leaf very enlarged, in a microscope, for example, we would observe that on the underside (i.e. in the part below the leaf), there are the stomata, which are those that allow oxygen, carbon dioxide, gases and water to leave and enter the leaves. In summary, we can say that the primary functions are photosynthesis, respiration, and transpiration.
The leaf is the plant organ of laminar shape and generally of green color due to the chlorophyll it contains; it is inserted in the nodes of both the stem and the branches. Its parts are: The blade: it is the flat part of the leaf, and has two faces, the upper one is called beam, and the reverse side called the underside.
The petiole: it is the filament that joins the leaf to the stem or branch.
The sheath: is the widening of the petiole or blade that envelops the stem.
The margin: the outline of the leaf, it can be toothed, wavy or smooth.
Leaves have the ability to adapt to the conditions in which the plant lives and adopt the shape and structure that are most useful and convenient; that is why leaves have a great variety of shapes and sizes: there are very small, or very large, such as those of ‘Adam’s rib’ or those of palm trees, some are simple, and others are compound. Those of pine trees, for example, are needle-shaped, others are elongated, elliptical, heart-shaped, rounded, etc.
I invite everyone to read Matias’ post with the topic of the day.
El Arbol de la Vida - Tercer Ciclo 