The role of carbohydrate reserves in regeneration of plants. I. Carbohydrate changes in subterranean clover following defoliation

Abstract

A study was made of changes in the total available carbohydrate of subterranean clover sown at different densities. Swards were subjected to a single defoliation at various dates, and sampled for carbohydrate analysis at intervals after defoliation. The carbohydrate content was much higher, and the decrease after defoliation much greater, in the tops than in the roots. The rate of decline decreased with increasing time after defoliation and the decline was followed by a period of recovery. No consistent effect of plant density was apparent. These results conform to those of previously published experiments for other pasture grasses. It is postulated from other data presented that the percentage decrease in non-structural carbohydrate after defoliation follows largely its use as respiratory substrate, and, to a lesser extent, as material translocated to the roots and in syntheses at new growing points. The significance of these changes is discussed, and it is concluded that further physiological research is required to justify the widely held belief in the importance of "reserve" substances to regrowth.