Parenchyma is involved in a wide variety of functions, such as photosynthesis, storage, the synthesis of organic compounds, and tissue repair. It consists of a single cell type: the parenchyma cell. Parenchyma tissue is found in the cortex and medulla of shoots and roots, leaf mesophyll, flesh of fruits, and seed endosperm. Parenchyma cells are also found as components of the vascular tissues: phloem and xylem.
According to the function, four types of parenchyma tissues are found:
The chlorophyll parenchyma, or chlorenchyma, is specialized in performing photosynthesis, which is carried out by the many chloroplasts found in the cytoplasm of their cells. The chlorophyll parenchyma is commonly found under the epidermis, where the light is intense. This tissue is mainly found in the leaves and in the peripheral region of green stems. The chlorophyll parenchyma of the leaves is known as the mesophyll.
Storage parenchyma synthesizes and stores substances. Starch is the most common storage compound.
Aquiferous parenchyma. Although all plant cells are able to accumulate more or less water intracellularly, the aquiferous parenchyma cells are specialized in this function, which is critical for xerophyte plants (those leaving in dry environments). These cells show a very large vacuole where water is stored. Aquiferous parenchyma may be regarded as a very specialized storage parenchyma.
The aeriferous parenchyma, or aerenchyma, shows large intercellular spaces connected to one another, allowing gases to be conducted through the tissue. This feature is necessary for hydrophytes (leaving in waterlogged and aquatic environments) in order to aerate the plant organs.
Meristems 