1.1

• A plant consist of two tissue which are meristematic tissue and permanent tissue
• Meristematic tissues are actively dividing tissue through mitosis
• There are two meristematic tissues which are Apical meristematic tissue and Lateral meristematic tissue
• Permanent tissue : epidermal tissue , ground tissue and vascular tissue
• Ground tissue consist of parenchyma tissue, colenchyma tissue and sclerenchyma tissue
• Vascular tissues consist of xylem tissue and phloem tissue
• Permanent tissues are matured tissues which have experienced or are experiencinb differentiation
• Epidermal tissues layer the outermost surface of stems, leaves and roots of young plants
• Epidermal cell walls which are exposed to the air have a waxy and waterproof layer called cuticle
• The cuticle reduces loss of water through evaporation ( transpiration ) , protects the leaves from mechanical injuries and pathogens
• Modified epidermal cells consist of guard cells and root hair cells
• Guard cells control the opening of the stoma
• Root hair cells increase the surface area of the root to absorb more water and mineral salts
• Parenchyma tissues are simplest living cells in plants and do not undergo differentiation
• Parenchyma tissues has the thinnest cell walls
• Parenchyma tissues are always in turgid state providing support and mantaining the shape of herbaceous plants
• Parenchyma tissues are involved in photosynthesis , help in the storage of starch and sugar , and involved in gaseous exchange
• Parenchyma tissues are involved in the repair and regeneration of plant tissue as well as in the vascular system
• Collenchyma tissues are made of living cells which mature into cells that are flexible
• Collenchyma tissues have cell walls made of pectin and hemicellulose
• Collenchyma tissues has thicker cell walls than the parenchyma tissues
• Collenchyma tissues provide mechanical support and elasticity to plants
• Sclerenchyma tissues concist of dead cells when they are matured
• Sclerenchyma tissues has the thickest cell walls
• Sclerenchyma tissues provide support and mechanical strength to the parts of matured plants. Also helps in the transport of water and nutrients in plants
• Xylem is made up of dead cells without the cytoplasm
• The cell wall of xylem contain lignin
• Xylem consist of xylem vessel that are elongated , hollow and connected to each other from its roots to the leaves
• Xylem vessels allow xylem to transport water and mineral salt to all parts of the plant
• Phloem are made of companion cells and sieve tubes
• Phloems are made of living cells , which is the sieve tube with the presence of cytoplasm
• The sieve tubes of phloem do not have any organelles as they decompose at maturity stage
• Phloems consist of sieve tubes arranged from end to end forming elongated and continous tube structures
• Phloems transport sugar produced from photosynthesis from the leaves to storage organs such as roots , fruits and tubers