Leaf Structure

Leaf Structure

2.1

Leaf Structure

Leaf is an organ which consists of a lamina connected to stem by petiole
Lamina has a thin,flat and broad structure to absorb sunlight and carbon dioxide for photosynthesis
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
Epidermis	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
Xylem	Transport water and mineral salts from roots to leaf
Phloem	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