Abstract:

【Objective】 To explore the effects of elevated atmospheric CO₂ on the morphological appearance and levels of sucrose, fructose, and glucose inLycium barbarum fruits during the developmental period, and provide a reference for the impact of climate change on sugar accumulation during fruit development. 【Method】 L. barbarum fruits, as test materials, CO₂ concentration was controlled by open-top chamber(OTC)to simulate the natural environment: ambient [(380±20) μmol/mol, CK], increased [(570±20 μmol/mol, TR1], and double ambient CO₂ concentration [(760±20) μmol/mol, TR2]. Samples from the young fruit stage to the mature stage ofL. barbarum were exposed to different CO₂ concentrations, and the morphological indexes and sugar content at the developmental phase were tested. 【Result】 Single fruit weight and the transverse diameter of TR1 and TR2 were increased significantly in the young fruit and green fruit under elevated CO₂ concentration; moreover, the longitudinal diameter, and fructose and starch content increased significantly in the green fruits. Sucrose content in the ripened samples increased significantly in TR1 and TR2 compared to CK, although the transverse diameter remained the same, whereas, the ratio of longitudinal diameter to transverse diameter for single fruit was inverse, and there was no difference in fructose, glucose and starch mass levels. Sucrose to starch ratio in the colored, initial maturity and mature phase among the three treatments was disparate. Significant stimulative correlations were indicated in single fruit weight of green fruits and starch, single fruit weight of colored fruits and fructose, single fruit weight of mature fruits and sucrose content under elevated CO₂, as well as sucrose and starch content in colored fruits. 【Conclusion】 Based on the analyses, it can be concluded that elevated CO₂ increased the transverse diameter and weight of a single fruit of L. barbarum in young fruit and green fruit phase, facilitated the fructose and starch content in green fruit phase, and changed the process of sucrose and starch accumulation during fruit development. The single fruit weight and sucrose content ofL. barbarum were improved in mature fruits under elevated CO₂.

Key words: CO₂ concentration, Lycium barbarum L., morphological indexes, sugar accumulation