Palisade cell

From Wikipedia, the free encyclopedia

This does not cite its references or sources.
Please help improve this article by introducing appropriate citations. (help, get involved!) This article has been tagged since June 2006.

Transverse section of leaf showing palisade cells layered directly below upper epidermis of leaf.

Palisade cells are a type of mesophyll (plant tissue) and can be found within the leaves of all green plants. They contain chloroplasts, each of which contains several different photosynthetic pigments (arranged in photosynthetic reaction centres), which absorb sunlight, converting the energy stored in photons to chemical energy through photosynthesis.

Palisade cells show various adaptations: first, their cylindrical shape, which allows maximum absorption of light by chloroplasts. Second, these cells produce carbohydrates in greater quantities than are needed by each cell; these carbohydrates are fed into a wide variety of metabolic pathways and are vital to the functioning of the plant. Third, the palisade mesophyll contains the largest per-cell number of chloroplasts in the plant; usually positioned towards the upper surface of the leaf in order to harness the greatest amount of energy possible.

Palisade cells are placed near the top of a leaf, in order to maximise the amount of light absorbtion. This is why, the top of a leaf is often darker than the bottom.