Parenchymal tissue. Includes the main body part of the plant. It is a simple tissue with little specialization, made up of living cells at maturity, which retain their ability to divide.
Summary
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- 1 General
- 2 Function
- 3 Characteristics of parenchymal cells
- 4 Classification
- 1 Fundamental
- 2 Chlorophyll
- 3 Reserve
- 4 Aquifer
- 5 Aerifer
- 6 Parenchyma accompanying conductive vessels
- 5 Source
- 6 See also
General
The parenchymal tissue of the primary body of the plant is differentiated from the fundamental meristem, and the parenchyma that accompanies the conductive vessels, from the procambium . In plants with secondary growth, parenchyma can originate from the phylogen and the cambial activity. The parenchyma is located in the marrow and bark of the stems and roots, in the mesophyll of the leaves, in the flowers, in the fleshy parts of the fruits and reserve organs, in the endosperm of the seed, etc.
The parenchyma is made up of living cells, of variable morphology and physiology, related to the vegetative activity of the plant.
Function
In this fabric the essential activities of the plant are carried out; for example, photosynthesis, and the storage of water and reserve substances, activities that require the presence of living protoplasm. The parenchymal cells that are part of the xylem and phloem also play an important role in relation to the translocation of water, mineral salts and processed substances by the conductive elements.
Characteristics of parenchymal cells
They have to varying degrees the ability to resume meristematic activity, depending on the degree of specialization they achieve. They are large cells with a polyhedral shape, sometimes more or less elongated, generally with elongated, cellulosic primary cell walls. Sometimes the cell walls can be thick with numerous pits, as occurs in the endosperm of many seeds. Large vacuoles are present that retract the cytoplasm into the cell wall. The cellular content is closely related to its physiological activity.
Classification
According to its physiological activity and structure, the parenchyma can be subdivided into:
- Fundamental
- Chlorophyll
- Backup
- Aquifer
- Aeriferous
- Parenchyma that accompanies the conductive vessels.
Fundamental
It is the least specialized, they are isodiametric cells, with thin primary walls; It is found as a filler among other tissues, in the medullary region and in the cortex. Retaining its ability to divide by mitosis at maturity, this characteristic allows an entire plant to regenerate from a single cell by in vitro culture.
Chlorophyll
Photosynthesize. Its cells have a variable number of chloroplasts. In the mesophyll of the leaves this parenchyma differs into two types:
- Palisade: elongated cell with abundant chloroplasts and few intercellular spaces, generally located towards the leaf bundle.
- Lagunoso: irregular cells with few chloroplasts and abundant intercellular spaces, which allow gases to diffuse throughout the entire leaf structure, almost always located towards the underside of the leaf.
Backup
Stores proteins, starch, lipids and reserve substances. Common in roots, bulbs, rhizomes, tubers and seeds.
Aquifer
Stores water. Parenchyma of succulent plants, the presence of mucilage in the vacuoles allows the retention of large amounts of water.
Aeriferous
Also called aerenchyma . Tissue of aquatic plants that present large intercellular spaces, not only allows aeration, but is also a support and flotation element. The system of spaces is determined by the irregular or starry shape of the cells.
Parenchyma accompanying conductive vessels
Generally of thickened primary or secondary walls. They are found between the cells of the xylem and phloem of the vascular bundles.