Palisade cell Palisade cell Palisade cells are plant cells located in leaves, right below the epidermis and cuticle. They are vertically elongated, a different shape from the spongy mesophyll cells beneath them in the leaf. Their chloroplasts absorb a major portion of the light energy used by the leaf. Palisade cells occur in dicotyledonous plants, and also in the net-veined monocots, the Araceae and Dioscoreaceae. Palisade cells contain the largest number of chloroplasts per cell, which makes them the primary site of photosynthesis in the leaves of those plants that contain them, converting the energy in light to the chemical energy of
Fractionation of carbon isotopes in oxygenic photosynthesis be less fractionated in C (ie, δC is relatively less negative) compared to C3 plants with low water-use efficiency. C4 plants have developed the C4 carbon fixation pathway to conserve water loss, thus are more prevalent in hot, sunny, and dry climates. These plants differ from C3 plants because the Calvin Cycle in C4 plants produces a four-carbon molecule, malate (rather than 3-phosphoglycerate), after fixation of CO. Malate, the four-carbon compound is the namesake of "C4" photosynthesis. This pathway allows C4 photosynthesis to efficiently shuttle CO to the RuBisCO enzyme and maintain high concentrations of CO within bundle sheath cells.