- D Sivakumar and L Korsten
- Department of Microbiology and Plant Pathology, University of Pretoria, Pretoria 0002, South Africa
- 2005
Micro-cracking is a serious concern for litchi growers since it affects the postharvest quality of the fruit. In order to understand the processes that lead to micro-cracking, a preharvest study was initiated to observe cuticle development. This preliminary report describes the initial observations made with Mauritius cultivar. Fruit development was studied at two-weekly intervals from fruit set till commercial maturity. Micro-cracking was observed 20 days after initial fruit set. Cuticle accumulated on the pericarp surface during fruit development. In Mauritius cv., cuticle accumulated over the entire surface of the epidermal layer from an early stage of fruit development. The cuticle lines were parallel to each other in the early stages, and became more wrinkled, compact and protruded as the fruit matured. This study will be extended to include other important litchi cultivar fruit.
Summary:
Micro-cracking is a significant issue for litchi growers as it affects postharvest fruit quality.
The study focused on the South African export cultivar Mauritius, observing fruit development from fruit set to commercial maturity at two-week intervals.
Micro-cracking was first observed 20 days after fruit set.
Cuticle accumulation occurs on the pericarp surface throughout fruit development, starting early in the epidermal layer.
Initially, cuticle lines are parallel but become more wrinkled, compact, and protruded as the fruit matures.
Pericarp development includes structural changes such as thickening and tubercle growth.
The study challenges previous findings by showing cuticle thickness increases with fruit maturity, contrasting with reports of cuticle thinning.
Drought-induced pericarp desiccation is a major factor causing fruit cracking and micro-cracking, leading to water loss and postharvest quality decline.
Litchi has few stomata on the pericarp, so water loss mainly occurs through cuticle transpiration.
The thick cuticle and spongy tissue structure play a role in water loss during fruit development.
Further research is needed on cuticular structure and its impact on desiccation rates to improve litchi fruit quality and reduce postharvest micro-cracking.