SEASONAL CHANGES IN STARCH CONCENTRATION IN RELATION TO TREE PHENOLOGY, ORCHARD MANAGEMENT AND ALTERNATE BEARING IN LITCHI (LITCHI CHINENSIS SONN.) IN SOUTH AFRICA

Like in all woody plants, carbohydrates are also important in the growth of litchi trees. There are strong seasonal influences in carbohydrate reserves which reflect the growth stages of a tree such as vegetative shooting, flowering and fruit growth. The starch reserves of HLH Mauritius litchi trees were determined as part of an orchard management program. Wood samples from the main branches of trees of various treatments were taken up to six times a year according to certain phenological stages of the trees. The starch content was analyzed using a modified AOAC method. Starch content varied from year to year, reflecting alternate bearing, as well as within a year, reflecting tree phenology. Vegetative growth, flowering and fruit growth reduced starch reserves while rest periods, such as the end of fruit growth until new vegetative flushing and the winter rest period, increased starch reserves again.