Simple Tissues (Main 3)

• Parenchyma cells have thin, flexible primary cell walls made of cellulose. They typically have a large vacuole and a loose arrangement that allows for air and nutrient storage.
• Parenchyma cells are involved in photosynthesis, storage (starches, oils, water, etc.), and wound healing. They can also differentiate into other types of cells under certain conditions.
• Parenchyma cells are found throughout the plant, including in the leaf mesophyll, stem cortex, root cortex, and fruit pulp. They often have a spherical or polyhedral shape.
• Parenchyma cells are alive at maturity, retaining the ability to divide and differentiate.
• Parenchyma cells are the most versatile and common type of plant cell, crucial for the plant's metabolic processes and regeneration.
• Collenchyma cells have thicker, uneven primary cell walls rich in pectin, which allows flexibility. The cell walls are especially thickened at the corners.
• Collenchyma cells provides mechanical support and flexibility to growing organs, enabling them to withstand various forces without restricting growth.
• Collenchyma cells are primarily located just below the epidermis in stems, leaves, and petioles. Their elongated shape is oriented along the axis of the organ they support.
• Collenchyma cells are alive at maturity, capable of stretching as the organ grows.
• Collenchyma enhances structural support mainly in areas of active growth, such as young stems and leaf veins.
• Sclerenchyma cells possess very thick, lignified secondary cell walls that provide rigidity. They are mainly composed of cellulose, hemicellulose, and lignin.
• Sclerenchyma cells are specialized for structural support and protection, contributing significantly to the plant's mechanical strength.
• Sclerenchyma cells are found in stems, roots, leaves, and around vascular bundles. There are two main types: fibers (long and slender) and sclereids (varied shapes, often star-shaped or branched).
• Sclerenchyma are typically dead at maturity, lacking cytoplasm and creating a rigid framework for the plant.
• Sclerenchyma cells are essential for the plant's structural integrity, preventing collapse under weight and resistance against external stresses.