Plant Cell Types PDF

Plant cell types  Types of plant tissues: I.Meristematic tissue - is actively dividing to produce new cells. “Meristematic tissue is the plant tissue that has the ability to divide actively throughout its life.” - consists of undifferentiated small cell, with dense cytoplasm and large nuclei...

Plant cell types  Types of plant tissues: I.Meristematic tissue - is actively dividing to produce new cells. “Meristematic tissue is the plant tissue that has the ability to divide actively throughout its life.” - consists of undifferentiated small cell, with dense cytoplasm and large nuclei. The cells differentiate into new tissue of the plant. - found at the meristems of plants: A. Apical Meristem- are located at the growing points at the tips of roots and stems and results in an increase in the length of these structures. B. Lateral Meristem- results in the growth in thickness or width of woody roots and stems. This tissue is also called cambium; cork cambium divides to form the cork cells that form the outer bark of a woody plant. Vascular cambium divides to make xylem and phloem tissue C. Intercalary Meristem It is located in the leaves and internodes at the intercalary position. These help to increase the length of the internode. It is found in grass, monocots and pines. It is a part of apical meristem and adds to the height of the plant. II.Permanent Tissue These are specialized in function and do not divide constantly. Differentiation of cells begins as soon as cells have been formed by cell division, and results in changes in structure. There are three groups of permanent tissue: 1.Epidermal Tissue - This is the outermost layer of cells that covers the roots, stems, and leaves. They are tightly packed, with no intercellular air spaces. The main function of the epidermal cells is to protect the underlying tissue from injury. a.Guard cells - are bean- shaped epidermal cells that occur on either side of a stoma- which is the opening that occurs on the surface of a leaf. The guard cells function to open and close the stoma, thus controlling the loss of water by transpiration b.Hair cells - are formed by an extension of the cell wall. The hair functions to increase the surface area of the root to maximize the uptake of water and nutrients 2.Vascular tissue - functions to transport and support. a. Xylem Tissue- transport water and mineral salts from the ground water through the roots to the stems and leaves. It consists of vessels and tracheids- both cells have cell walls that are strengthened with lignin and both types of cells are dead at maturity. b. Phloem Tissue- transport food from the leaves, where photosynthesis takes place, to areas undergoing growth or storage sites. Phloem tissue consists of long columns of sieve tubes and companion cells. III. Ground Tissue This type of tissue forms the body of the plant -responsible for support, storage, and photosynthesis.  There are three types of ground tissue: a.Parenchyma - thin walled and alive at maturity; often multifaceted. b.Collenchyma - thick walled and alive at maturity c.Sclerenchyma- thick walled and dead at maturity Parenchyma -found in the leaves and are responsible for photosynthesis Parenchyma cells are like the “workhorse” cells of a plant, doing many of the basic functions like photosynthesis, storage, and healing. Collenchyma Example: Celery StalksThe "strings" in celery are made of collenchyma cells, which provide structural support while still being flexible. Collenchyma cells are like the "support beams" in a building that can bend without breaking. Sclerenchyma Sclerenchyma cells are like the "armor" of a plant, providing tough protection and support.