Pg. 26-27 Pheno/Physiological Patterns of Litchi Trees

This paper is a report on phenological studies conducted with litchi trees and some associated physiological patterns related to the phenology. 

In the phenology studies the cyclic occurrence of events of tree and fruit development such as bud development, flowering, vegetative flushes, fruit set, fruit development, root growth, etc., were recorded. The determination of the seasonal pattern of starch accumulation and utilization was combined with this study to establish physiological indicators within the litchi tree. 

The litchi tree phenology differs substantially from many other subtropical tree crops in that leaf growth flushes always precede flowering and fruit development, thus eliminating much of the competition between leaf development and fruiting. The new leaves from the first flush are in fact able to contribute to the carbohydrate energy requirement of
the flowering process, and later, the leaves of both flushes contribute to fruit development. 

The most important physiological process of the litchi tree (and in fact in all plants) is that of photosynthesis which involves the harnessing of light energy for the initial production of sugars from carbon dioxide and water. This supplies the plant with a source of chemical energy and basic building units for the reactions that take place. 

The litchi tree stores most of its carbohydrate reserves as starch in its thinner branches of 10 mm to 50 mm
diameter (Menzel et al., 1995). This also differs from other tree crops, e.g. mango trees, where starch reserves are stored mainly in the roots, main stem and frame branches (Davie et al.,1995). The litchi tree appears to have a relatively small root structure. Studies by Menzel et al. (1995) on excavated litchi trees indicated that the ratio of root dry material to aerial dry matter is of the order of 1 :6 (i.e. 1 kg roots for every 6 kg of plant matter above ground level) while the ratio with mango trees is about 1 :3,5 ( Davie et al., 1995).