通过调节源—库关系以改善荔枝座果

开花座果期连绵阴雨常导致荔枝严重落果失产,试验证明为保证正常座果,荔枝需有很大叶果比,这与其光合效率低有关,人工遮阴或喷光合抑剖剂严重降低座果。认为荔枝座果在很大程度上依赖于当时光合产物。由于荔枝果实有很强的“库”能力,故增强“源”对座果极为重要,喷光合促进剂,尤其在阴天情况下,可明显提高光合效率并大辐度改善座果。.

IMPROVEMENT OF FRUIT-SET IN LITCHI CHINENSIS SONN. THROUGH REGULATION OF SOURCE-SINK RELATIONSHIPS

Crop losses in Litchi chiuensis are often associated with overcast and rainny weather occurring during the blooming and fruit-setting period.It has been proved experimentally that high leaf-to-fruit ratio is essential to a normal fruit-set due to the low net photosynthetic efficiency of litchi leaves.Artificial shading of litchi leaves to imitate overcast weather or spraying of photosynthetic inhibitor (DCMU) caused serious fruit shedding.It is suggested that litchi fruit-set relies greatly on current photosynthates.Litchi fruits,possessing strong sink strength,could mobilize adequate amount of assimilates from without the defoliated fruiting shoot in support of a normal set and a full development of retained fruits.The increase of a source capacity,however,is of primary significance to the set.Spraying of a photosynthetic promoter (necleotide) significantly enhanced the photosynthetic rate of litchi leaves,especially in overcast weather,and thus greatly increased fruit set.