Control of carbon partitioning in plants

Abstract

Abstract My remit embraces the whole of intermediary metabolism: my intention is to concentrate on the central emerging hypothesis that the control of sucrose metabolism is the key to partitioning in higher plants (Farrar 1992). In this hypothesis sucrose is seen both as the major product of photosynthesis and as the main form in which the non-photosynthetic cells of the plant receive their carbon and energy. Photosynthetic cells are regarded as exerting control over the rest of the plant by regulating the latter’s supply of carbon and energy. The non-photosynthetic or ‘sink’ cells of the plant, in turn, are seen as influencing the photosynthetic cells by an ability of sucrose or its products to diminish the rate of photosynthesis. This inter-relationship could form the basis of the allometric growth of plants illustrated by the constant ratio of the relative growth rates of shoot and root. l shall concentrate on leaf metabolism, as partitioning in sinks has recently been discussed in detail (Pollock et al. 1992).