Leaf Structure

2.1 Leaf Structure
  1. Leaf is an organ which consists of a lamina connected to stem by petiole
  2. Lamina has a thin,flat and broad structure to absorb sunlight and carbon dioxide for photosynthesis
  3. Leaf is provided by a network system of vein throughout the lamina.
  • Vascular tissues in vein transport water,mineral salts and photosynthesis products continuously and effectively
  • The network of vein combines to form a main vein and connects to vascular tissues of stem through petiole
Structure of leaf Function
  • A transparent layer allows sunlight penetration into leaf
  • Secretes cuticle to reduce water loss from leaf
  • Protects leaf tissues from injury and entry of pathogens
Palisade mesophyll
  • Cylindrical shaped of cells which contain chloroplasts
  • Can carry out photosynthesis
  • Closely arrangement of palisade mesophyll cells to absorb sunlight maximally for photosynthesis
Spongy mesophyll
  • Irregular shaped of cells which contain chloroplasts
  • Can carry out photosynthesis
  • Loosely arrangement of spongy mesophyll cells to form air spaces for carbon dioxide and water evaporation
  • Transport water and mineral salts from roots to leaf
  • Transport organic products from leaves to other parts of plants
Vascular bundle
  • Component of vascular tissue in plants consisting both phloem and xylem
Guard cell
  • Kidney shaped cells on leaf epidermis
  • Two guard cells join at both cellll ends to form a stoma
  • Control opening and closing of stomata for gaseous exchange and transpiration