Coconut husk fibres contain sclerenchyma with thick lignified walls, making them hard and brittle. Coriander leaf stalks contain collenchyma with unevenly thickened walls and pectin, providing softness, flexibility and support without breaking during bending or movement.
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Supporting tissues keep plants upright. Collenchyma provides flexibility, allowing fresh twigs to bend without breaking. Sclerenchyma makes seed coats hard and strong. Specialised parenchyma with air spaces helps aquatic plants float easily on water surfaces.
The epidermis protects plants from mechanical injury, water loss, microorganisms and harsh environmental conditions. Its tightly packed cells and waxy cuticle reduce water loss, while root hairs and stomata help absorption, gaseous exchange and transpiration in plants.
Different types of cells and tissues are present because organisms perform many specialised functions. Cells become structurally modified for particular tasks like protection, transport, support, movement and coordination, improving efficiency through division of labour in multicellular organisms.
Meristematic cells lack vacuoles because they divide continuously and need dense cytoplasm for active metabolism. Large vacuoles would occupy space and reduce the efficiency of rapid cell division required for plant growth and tissue formation.