We know that like animals, plants are made of tissue. In plants, these tissues are grouped into three systems: dermal system, vascular system and fundamental system. Tissues belonging to the fundamental system are the parenchyma, colenchyma and sclerenchyma. The parenchyma will be the focus of our study.
O parenchyma is a tissue composed of living cells with meristematic properties, that is, capable of cell division. Thanks to this property, they are very important for the plant in the healing process. This tissue is related to the most varied functions in the plant, including the storage of substances, photosynthesis, secretion and transport.
Parenchymal tissue cells are generally isodiametric, however the shape may vary. They commonly have thin primary walls, but sometimes the walls may lignify. In parenchyma with primary walls, primary punctuation fields occur. The vacuoles are usually well developed in these cells.
An important feature of this tissue is the presence of intercellular spaces formed by the separation of cells due to the dissolution of the middle lamella. These spaces are called schizogenous spaces.
Parenchymal tissue is found in all plant organs. In the root and stem, this tissue is found forming the cortex and medulla. In leaves, it is found forming the mesophyll. The parenchyma may also be associated with vascular tissues.
Parenchyma tissue can be divided into three types: filling parenchyma, chlorophyllian parenchyma and reserve parenchyma.
O filler parenchyma it is formed by cells of varying sizes and shapes. It is found forming the cortex and medulla of stems, roots, petioles, and the rib region of the leaves.
O chlorophyllian parenchyma it is related to the photosynthesis capacity of the plant, so it has a large amount of chloroplasts. It is found mainly in leaves and, in these organs, it has a great capacity to respond to variations in the environment.
The chlorophyllian parenchyma can be classified into: palisade, spongy, regular, plicated and braciform. The palisade parenchyma has tall cells and has little intercellular space. The spongy (or spongy) parenchyma is characterized by irregularly shaped cells and the presence of intercellular spaces. The regular parenchyma presents cells with a rounded shape. The plicated parenchyma has recessed cells. The braciform parenchyma has cells with projections that delimit gaps.
O reserve parenchyma its main function is to store substances. It can be classified according to the substance it stores into: amiliferous parenchyma, air and aquifer. The starchy parenchyma has cells that contain starch grains, which can be found, for example, in potatoes and cassava. The air parenchyma stores air in intercellular spaces and is found in aquatic plants. The aquifer parenchyma, in turn, found in succulent plants, has the function of storing water.
by Vanessa dos Santos
Graduated in Biology
