parenkyymä

Parenchyma is a fundamental type of plant tissue. It is one of the three main types of ground tissue, the others being collenchyma and sclerenchyma. Parenchyma cells are living at maturity and are the most common type of plant cell. They are typically spherical or polyhedral in shape and have thin primary cell walls. These cells are responsible for a wide range of functions in plants, including photosynthesis, storage of food reserves, secretion, and regeneration.

Parenchyma tissue is found throughout the plant, including in roots, stems, leaves, flowers, and fruits. In leaves, parenchyma cells, specifically called mesophyll, are the primary sites of photosynthesis. In roots and stems, parenchyma can serve as storage tissue for starch, lipids, and proteins. Some parenchyma cells have specialized functions, such as transfer cells that facilitate the movement of substances, or secretory cells that produce and release substances like nectar or resins.

The ability of parenchyma cells to divide and differentiate is crucial for plant growth and repair. If a plant is injured, parenchyma cells can dedifferentiate and divide to form new tissues, contributing to wound healing. They also play a role in vegetative propagation, where new plants can be grown from cuttings or other plant parts, relying on the totipotency of parenchyma cells. The thin cell walls of parenchyma allow for easy movement of water and nutrients, as well as gas exchange.