Saturday, 22 May 2021

The various components of a monocot leaf are epidermis

   The various components of a monocot leaf are epidermis




It is surrounded by parenchymatous ground tissue. Vascular bundles have conjoint, collateral but closed nature with xylem towards the upper side and phloem towards the lower side. Reasons for Identification : (i) Bifacial flattened structure with stomata nmostly on lower surface. (iii) Vascular bundles with colourless bundle sheath. 

Internall Structure of an Isobilateral Monocot Leaf : (Fig. 6) In monocot leaves the two surfaces are equally green and liable to face the sun. They are, therefore, called isobilateral leaves (Gk. isos equal, bis side).

 The various components of a monocot leaf are epidermis, mesophyll, vascular twice, latris strand and midrib. (1) Epidermis : It is the outer most covering of the lamina on both the surfaces. The cells are parenchymatous rectangular barrel shaped. They are devoid of chloroplasts and are, therefore, transparent.

 Free surface of the epidermal cells possesses cutin and silica thickenings. Separate layer of cuticle is also present. At places the adaxial epidermis of Maize and a number of grasses possess large sized thil.walled colourless protruding cells called bulliform or motor cells. They become flaccid when water is deficient. Consequently, the leaves curl inwardly to minimise exposed surface.

 The leaves become flát again when water is available and bulliform cells become turgid. Bulliform or motor cells, therefore, take part in folding and unfolding of leaves depending upon the moisture content of the atmosphere. Stomata occur on both the surfaces with almost equal frequency. 

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