Tag: kinds of plant tissue

Epidermis is the outermost protective layer which minimizes the loss of water by transpiration. Some plants, like Ficus elastica and Peperomia, which have periclinal cellular division within the protoderm of the leaves, have an epidermis with multiple cell layers.

Each stomatal pore is surrounded by two guard cells that assist in stomatal opening driven by turgidity of guard cells. The only epidermal cells with unevenly thickened walls and chloroplasts are the guard cells, they are kidney shaped in dicots and dumbell shaped in monocots.

Epidermis is the part of epidermal tissue system and forms the outer protective covering of primary plant body. The epidermal cells secrete cutin, which is a hydrophobic substance and prevents water loss and desiccation. The cutin forms a covering outside the epidermal cells in all plants parts except root.

• Cork cells are dead and have cell walls composed of a waxy substance "suberin", which is highly impermeable to gases and water. This substance prevents water loss from stem. Therefore, option B is correct.

The ground tissue system synthesizes organic compounds, supports the plant and provides storage for the plant. It is mostly made up of parenchyma cells. Parenchyma cells synthesize and store organic products in a plant. Parenchyma cells in leaves control photosynthesis. Collenchyma cells have a support function in plants, particularly in young plants. Mesophyll tissue is the photosynthetic parenchyma cells that lie between the upper and lower epidermis layers of a leaf. In dicotyledonous leaves, there are two types of mesophyll cells; palisade mesophyll and spongy mesophyll.

• In deserts, water is scarce and saving water is a major step which plants of this region have to undertake. So in many of the desert plants like Yucca, creosote, cactus, etc, the epidermis has a thick waxy coating of cutin. 
• This restricts the loss of water through transpiration. In desert plants, the epidermis has a thick waterproof coating that is not made of suberin, elastin or chondrin. 

The epidermis cells is a single layer of cells that covers the leaves, flowers, roots and stems of plants. It forms a boundary between the plant and the external environment. Cork cambium is a tissue found in many vascular plants as part of the periderm. The cork cambium is a lateral meristem and is responsible for secondary growth that replaces the epidermis in roots and stems. The pericycle is a cylinder of parenchyma or sclerenchyma cells that lies just inside the endodermis and is the outer most part of the stele of plants. Cortex, in plants, the tissue of unspecialized cells lying between the epidermis (surface cells) and the vascular, or conducting, tissues of stems and roots. 

• Cork cells are formed as a part of the bark. The waterproof waxy layer present on the cork cell is the suberin., Quercus suber. Its main function is as a barrier to the movement of water and solutes. Suberin is highly hydrophobic and a somewhat 'rubbery' material. In roots, suberin is deposited in the radial and transverse cell walls of the endodermal cells. 
• This structure, known as the Casparian strip or Casparian band, functions to prevent water and nutrients taken up by the root from entering the stele through the apoplast. Pectin, lignin, and cellulose are not hydrophobic materials. 

A root hair is the minute structures generally, present on the stem and the roots. It is a tubular outgrowth of a trichoblast, a hair-forming cell on the epidermis of a plant root.

• The epidermis is the outermost covering and acts as a protective layer. it is formed initially by protoderm. 
• These are thin-walled as they are generally made up of parenchymatous cells. 
• The epidermis serves several functions, it protects against water loss, regulates gas exchange, secretes metabolic compounds, and (especially in roots) absorbs water and mineral nutrients. 
• The epidermal tissue includes several differentiated cell types of epidermal cells, guard cells, subsidiary cells, and epidermal hairs (trichomes). They have thin-walled cells.