A Minireview: Comparative Biochemistry of Photosynthesis in Palisade Cells, Spongy Cells, and Guard Cells of C3 Leaves

Abstract

In broad terms plant biochemists differentiate only two classes of leaf chloroplasts (C3 chloroplasts and C4 mesophyll chloroplasts). However, anatomists distinguish many more, even within the mesomorphic dicotyledonous leaf (1). Surprisingly, the potential for biochemical differences among these plastids has been of little interest to experimentalists. The purpose of this brief overview is to summarize and compare selected biochemical attributes of chloroplasts from three types of C3 leaf cells (viz., palisade parenchyma, spongy parenchyma, and guard cells). Because of space constraints, this paper is not comprehensive; instead, it displays representative results. This area of comparative biochemistry is undeveloped, and I hope this first review of it will stimulate further work.