2,4-表油菜素内酯(EBR)对网纹甜瓜光合特性和果实品质的影响

2,4-epibrassinolide's Effects on Photosynthetic Characteristics and Fruit Qualities of Netted Melon

本文采用不同浓度的2,4-表油菜素内酯(EBR)处理不同发育阶段的网纹甜瓜植株,观察EBR处理植株和对照植株的光合相关指标的变化,分析收获后EBR处理和对照植株之间果实品质的差异。结果表明,提高网纹甜瓜光合速率的最有效的EBR浓度是0.1 mg·L-1。在幼苗期和初花期植株中,EBR处理改善了净光合速率(Pn)和气孔导度(Gs),同时降低了胞间CO2浓度(Ci)和蒸腾速率(Tr),而EBR对光合速率的改善是由于非气孔因素所致。在结果后期,EBR处理植株的Pn、Gs和Ci均高于对照植株,而Tr则低于对照;EBR处理植株的光合能力的上升是由于气孔因素所致。EBR可以有效地提高果实的纵径和横径,显著提高果实重量;EBR促进果实和重量增大的原因可能是EBR直接促进了细胞的生长和分裂。此外,EBR处理植株果实的可溶性固形物含量也出现显著地提高。根据上述结果推测EBR能提高网纹甜瓜植株的光合速率,促进碳水化合物从叶片向果实的转运。本研究有助于进一步探究BR类物质对甜瓜植株光合作用以及果实品质影响的作用机理,同时也为网纹甜瓜优质高产栽培提供理论依据和方法指导。

EBR improved net photosynthetic rate （Pn） and gas conductance （Gs）, while EBR reduced intercellular CO2 concentration （Ci） and transpiration rate （Tr） of melon plants, suggesting that in these two stages, EBR＇ s improvement of photosynthetic rate were probably attributed to non-stomatal factors to a large extent. In late-fruiting phase, Pn and Gs, and Ci of EBR-treated plants were all higher than the control＇ s whereas Tr of that is lower than the control＇ s. In late-fruiting phase, elevated photosynthetic capacity bred by EBR were probably due to stomatal factors. It is also found that EBR treatment effectively increased longitudinal and horizontal diameters of fruits. In addition, fruit weight was also effectively increased by EBR treatment. It is speculated that these changes could be attributed to direct increase of cell growth and division by EBR treatment. Moreover, EBR significantly improved total soluble sugar content of netted melon. Therefore it is reasoned that EBR promoted transportation of carbohydrate from leaves to fruits by uplifting photosynthesis rate.