Plant tissues

• Enchyma may be involved in storage functions and short distance transport of solutes (transfer cells).
• Phloem fiber provides mechanical strength.
• Vascular tissue is involved in food translocation.
• A plant tissue is a group of cells that came from the same origin, are similar in structure and perform the same function.
• Meristematic tissues are actively dividing.
• Permanent tissues are differentiated cells.
• Meristematic tissues are based on the ability of cells to divide.
• Simple tissues consist of one type of cell.
• Complex tissues consist of more than one type of cell.
• Meristematic tissues are responsible for primary growth.
• Secondary tissues are responsible for secondary growth.
• Apical meristem, intercalary meristem, and lateral meristem are types of meristematic tissues.
• Meristems elaborate the plant body after germination.
• Meristematic tissues can be found in the growth regions of plants, such as roots and shoots.
• Plants have three basic tissues: dermal tissues, ground tissues, and vascular tissues, each composed of several cell types.
• Dermal tissues are derived from protoderm and are one cell thick in most plants, covered with a waxy layer (cuticle).
• Guard cells are paired dumbbell-shaped cells flanking a stoma (epidermal pore), contain chloroplasts, and regulate the opening and closing of stoma.
• In vascular plants, the shoot and root systems are part of the organization of the plant body.
• Root hairs are tubular extensions of epidermal cells that keep the root in intimate contact with the surrounding soil particles, greatly increasing the root’s surface area for absorption.
• Parenchyma is widely distributed in plant tissues.
• Coordination of primary and secondary growth produces the body of the adult plant.
• Ground tissues form the bulk of the softer parts of plants, are involved in storage, basic metabolism and support, and are composed of parenchyma, collenchyma, and sclerenchyma.
• Trichomes are hairlike outgrowths of the epidermis that occur frequently on stems, leaves, and reproductive organs, keeping the leaf surface cool, reducing the rate of evaporation, and deterring herbivores.
• Under the bark (cork cambium) and vascular bundles of woody dicot roots and stems (vascular cambium) are involved in secondary growth, which is the increase in girth of root and stem (horizontal growth).
• Parenchyma is the least specialized of the ground tissues, is oval, rounded, polygonal or elongated in shape, has a thin cell wall, dense cytoplasm with small nucleus and large central vacuole, and many intercellular spaces.
• Apical meristem is located at the tips of roots (root apex) and shoots (shoot apex) and is responsible for primary growth, which includes the increase in length of root and shoot (vertical growth) and the production of primary meristems.
• Intercalary meristem is located at the base of leaf, i.e., leaf sheath in grasses, and is also responsible for primary growth, which includes the increase in length.
• Lateral meristem is located in lateral positions.
• Collenchyma cells have unevenly thickened cell walls and deposition of pectin in their cell walls.
• Secondary xylem tissue, commonly called wood, developed from the vascular cambium.
• Xylem tissue consists of four cell types: tracheids, vessels, xylem parenchyma, and xylem sclerenchyma, all of which are dead (lignified) except for xylem parenchyma.
• Aerenchyma, another specialized form of parenchyma, has large air cavities for buoyancy in aquatic plants or for improved gas exchange.
• Parenchyma serves as packing tissue (fill-in) between tissues, maintains shape and firmness of the plant, and is involved in storage of food, nutrients, water, etc.
• Xylem tissue functions as a vascular tissue that conducts water, dissolved mineral salts and inorganic compounds such as nitrates and phosphates, and as a mechanical tissue that provides support.
• Chlorenchyma, a specialized form of parenchyma, contains chloroplast/chlorophyll for photosynthesis.
• Transfer cells are specialized forms of parenchyma that are involved in short distance transport of solutes.
• Vascular tissues are composed of several kinds of cells, specialized for long transport of water and dissolved solutes, and have two types: xylem and phloem.
• Sclerenchyma cells are dead at maturity, have deposition of lignin in the cell walls, and have no intercellular spaces.
• Phloem tissue consists of four elements: sieve tube members, companion cell, phloem parenchyma, and phloem fiber, with phloem cells being living except for phloem fiber.
• Sieve tube members are short and wide cells arranged end-to-end with a large cluster of pores called sieve areas.