GROWTH AND DEVELOPMENT OF LITCHI CHINENSIS AS AFFECTED BY SOIL‐MOISTURE STRESS

Abstract

The effects of soil‐moisture tension on growth and floral development of field‐grown Litchi chinensis, a woody subtropical fruit tree, were investigated. Floral initiation and fruit set were promoted by a high soil‐moisture tension for 6 months, beginning with June, 1967, or for 4 months, beginning with October, 1967. The normal floral‐initiation period in Hawaii is during the period November to January. The apical meristematic tissue, judged from the number of branches flowering, was apparently not adversely affected by a soil‐moisture stress, provided adequate water was available during the floral‐bud development period. Low soil‐moisture tension (0.3 bar) throughout the experimental period was inhibitory for floral bud initiation. High soil‐moisture tension inhibited growth of the trunk and the emergence of flush‐growths. Flowering was correlated significantly, and negatively, with growth. Leaf nitrogen and potassium levels were unaffected by water stress, but the phosphorus levels in leaf and stem were lowered by high‐moisture tension. Hydrolysis of starch under moisture stress, reported for some species, was not evident in the Litchi. No correlation between trophic constituents and flowering was observed.