ABSTRACT
The biochemistry of plants is sufficiently distinctive to merit separate treatment from that of other organisms. This is for two main reasons. First, the sessile plant cannot avoid environmental stress or predation by moving away, and second, plants are autotrophic and their resources are relatively simple (e.g. inorganic nutrients, light, water, and carbon dioxide) and frequently in short supply. The second major feature that marks out plant biochemistry is the autotrophic nature of plants—hence, even respiratory pathways such as the tricarboxylic acid cycle, which are primarily catabolic in non-photosynthetic organisms, serve an anabolic function in plants, providing carbon skeletons for biosynthesis. The way in which plants acquire and reduce inorganic nitrogen is a good example of how environmental conditions influence plant biochemistry. Lipids are not only essential to the structure of cells but they also serve as important respiratory substrates in certain plant tissues (e.g. oily seeds).
