Cellular Aspects of C4 Leaf Metabolism
The discovery of C4 photosynthesis heralded the beginning of a new understanding of cellular specialization among the leaf cells of higher plants. The essence of C4 photosynthesis and of this new understanding of leaf metabolism can be stated simply: two green cell types are always found in a C4 plant; and these cells do not have a fixed morphological or anatomical arrangement but share, in an interdependent manner, the tasks of photosynthetic energy capture, storage, and utilization. By taking this view of the C4 plant, we will describe photosynthetic metabolism in C4 leaf cells as a cooperative activity between the mesophyll cells, which trap atmospheric CO2 as readily transportable (but nevertheless reactive) four-carbon acids, and the bundle sheath cells, which decarboxylate the acids and refix the CO2 via the C3 cycle. This character of interdependence among leaf cells in which cell type has several required roles to complete a metabolic cycle is not a characteristic of C3 photosynthesis plants.
KeywordsMesophyll Cell Bundle Sheath Bermuda Grass Bundle Sheath Cell Cellular Aspect
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