The influence of exogenous ABA level on the growth of cherry tomato under low light

Background : Light is a primary factor for plant growth and fruit development, and exogenous ABA also plays an essential role in metabolism of plants. Previous studies have documented that low light [LL] led to the adverse changes in morphology and physiology of cherry tomato, while exogenous ABA has been proven to be effective in improving plant tolerance to abiotic stresses. However, few works have explored the effects of exogenous ABA on the vegetative growth and quality formation of cherry tomato under [LL]. In the present study, the combined effect of [LL] and exogenous ABA on the plant growth and fruit quality of cherry tomato were investigated. Methods : Three levels of exogenous ABA (Control (CK), 0 μM; A1, 38 μM; A2, 76 μM) were set under two light regimes, including normal light intensity (100%, [NL]) and low light intensity (50%, [LL]). Results : The results showed that [LL] increased plant height but decreased stem diameter and total soluble solids (TSS); conversely, reduced plant height and elevated stem diameter were found in the plants treated with exogenous ABA. Under [LL], A1 (38 μM) decreased leaf gas exchange, WUE leaf , as well as WUE i , whereas A2 (76 μM) enhanced the WUE i of plant without effect on net photosynthetic rate (An), transpiration rate and WUE leaf . Moreover, A2 (76 μM) significantly elevated TSS and fruit firmness (FM) without compromising fruit yield. Conclusion : The study demonstrated that higher levels of exogenous ABA promote plant growth, leaf gas exchange, water use efficiency, and fruit quality in cherry tomato under [LL].