Video Transcript
What type of simple tissue in plants is described as a nonliving tissue comprised of cells that have thick walls hardened with lignin?
To answer this question, let’s look at the three different types of simple plant tissue: parenchyma tissues, collenchyma tissues, and sclerenchyma tissues. Parenchyma tissues are made up of parenchyma cells, which have a thin cellulose cell wall and make up most of the soft tissues found inside the leaves, stem, and roots. The cell wall of parenchyma cells does not contain any lignin, and water can pass through their cell wall easily. Parenchyma cells are living cells that carry out a number of functions: photosynthesis, storage of water and nutrients, secretion of sap, and assistance with aeration.
Collenchyma tissues are composed of collenchyma cells, which are longer than parenchyma cells. Their cell walls were believed to be composed of cellulose and pectin. And in 1950, scientists discovered that they also contain hemicelluloses. They are essential to provide structure, support, elasticity, and flexibility in the growing regions of plants. For this reason, they are most likely to be found below the epidermis of leaf veins and stems.
The final tissue type is sclerenchyma tissue. These are the toughest of the three simple tissue types and are used to reinforce strength. They are most often found in the vascular tissues of a plant, where they provide support. They are also found in the cortex of the stems, leaves, and any fruit produced. Mature sclerenchyma cells are usually dead. And they have very thick cell walls made of cellulose, hemicelluloses, and a chemical called lignin, which makes the cells waterproof. Collenchyma cells also have thick walls, but they may be thinner than the cell walls of sclerenchyma cells.
Now that we have reviewed each of the kinds of simple tissue in plants, we know that the nonliving tissue comprised of cells that have thick walls hardened with lignin is sclerenchyma.
