JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD Pharm. D I Year REMEDIAL BIOLOGY Previous Question Paper (September/October - 2021 - R08)

Plant organization is hierarchical, progressing from cells to tissues, organs, and organ systems. The plant body is primarily divided into the root system and the shoot system. Within the plant cell, cell inclusions are non-living materials stored within the protoplasm or cell wall, categorized as follows:

• Reserve Food Materials: These include carbohydrates (starch grains), proteins (aleurone grains), and lipids (oils and fats) stored for metabolic needs.
• Secretory Products: These consist of pigments (chlorophyll, anthocyanins), enzymes, nectar, and essential oils.
• Excretory Products: These are metabolic byproducts often deposited as crystals, such as calcium oxalate (raphides, druses) or calcium carbonate (cystoliths), as well as tannins, resins, and gums.

The dermal tissue system, or epidermis, forms the outermost protective covering of the plant body. It serves as the interface between the plant and its environment, regulating gas exchange and preventing water loss.

• Epidermis: Typically a single layer of tightly packed, thin-walled parenchyma cells. In aerial parts, it is covered by a waxy cuticle to reduce transpiration.
• Stomata: Specialized pores found primarily on leaves, flanked by two guard cells. These regulate the exchange of gases (CO2, O2) and water vapor.
• Trichomes: Hair-like outgrowths of the epidermal cells. They can be unicellular or multicellular and function in protection against herbivores, reducing water loss, or secreting substances.
• Root Hairs: Unicellular extensions of epidermal cells in the root zone, which significantly increase the surface area for the absorption of water and minerals from the soil.