Plants have three main tissue systems: the epidermal, ground, and vascular tissue systems. These systems serve various functions, including protection, support, and transport.
1. Epidermal Tissue System:
o Structure: Outermost protective layer covering the entire surface of the plant.
o Components:
§ Epidermis: A single layer of cells, usually covered by a waxy layer called the cuticle to reduce water loss.
§ Stomata: Openings in the epidermis that facilitate gaseous exchange. Each stoma is surrounded by two guard cells that control its opening and closing. These are more prominent in leaves.
§ Trichomes: Hair-like structures, present on the stems and leaves, play a role in reducing water loss and protecting the plant from herbivores.
§ Root Hairs: Extensions of the root epidermal cells that increase the surface area for water and nutrient absorption.
o Function: Provides protection against water loss, pathogens, and physical damage.
showing the epidermal system.
2. Ground Tissue System:
o Structure: Composed of parenchyma, collenchyma, and sclerenchyma cells.
o Parenchyma: Most abundant and responsible for photosynthesis, storage, and tissue repair. It’s present in the cortex, pith, and mesophyll.
o Collenchyma: Provides support to growing parts of the plant, especially young stems and leaves, due to its ability to stretch.
o Sclerenchyma: Dead cells providing mechanical support, consisting of fibers and sclereids.
o Function: Provides mechanical support and stores nutrients.