成串采收对番茄果实采后乙烯合成及贮藏品质的影响

为研究成串采收对番茄果实采后乙烯合成及贮藏品质的影响,对广西田阳县两个栽培区两种嫁接砧木的串收番茄的采后生理指标进行测定,探讨了该采收方式对番茄果实采后保鲜的作用机制。结果表明:整个贮藏期,不同栽培区不同嫁接砧木的番茄成串采收的果实,乙烯生成量明显低于对照的常规单果采收。其中,砧木1号Ⅰ区的串收番茄的乙烯生成量,采后5 d即下降至最低点(0.35 nL·g~(-1)·h~(-1)),显著低于其对照(1.36 nL·g~(-1)·h~(-1)),其他栽培区和砧木组合的串收番茄,在采后15 d乙烯生成量达到最低值。串收番茄的类胡萝卜素、番茄红素和抗坏血酸等果实内天然抗氧化物质的含量,在贮藏前期快速升高,且峰值显著高于对照。此外,成串采收处理还一定程度抑制了果实后熟阶段可溶性糖的积累和可滴定酸的分解。因此,番茄成串采收处理,可能通过抑制果实采后乙烯的合成,同时提高类胡萝卜素、番茄红素和抗坏血酸的水平,并且推迟糖和酸等营养物质的后熟变化进程,实现其延长果实货架期,提高商品品质的作用。

Effects of string-harvest on ethylene production and storage quality in post-harvest tomato fruit

Ethylene is a very important plant hormone, would cause rapid fruit ripening and softening. Keeping fruit freshness through regulation of ethylene biosynthesis and signal transduction is well studied. Tomatoes are typical climac-teric fruits, very sensitive to ethylene action, so their post-harvest ethylene responses always cause fruit deterioration during storage periods. Tomato string-harvest is to harvest a cluster of fruits with the stem, which is more applicable to the cherry tomato fruit type. String-harvest shows its superiorities like high yield and labor saving in tomato productions, and fruits are sold at higher prices because of their longer shelf-life. This study aimed to clarify the effects of string-har-vest trials on the ethylene production and storage quality in post-harvest tomato fruit, and to develop methods of exten-ding tomato shelf-life. Cherry tomatoes graft-cultivated with two rootstocks ( No. 1 and No. 3) from two production areas (Ⅰand Ⅱ) in Tianyang County of Guangxi Zhuang Autonomous Region in China, were taken as experimental materials. Tomatoes harvested by string (treatment) or single fruit (control), were analyzed for their changes in the rate of ethylene production, content of carotenoid, lycopene, ascorbic acid, soluble sugar and titratable acids. Moreover, re-sults indicate that throughout storage periods, ethylene production in string-harvest tomatoes with different rootstocks and cultivation areas were significantly lower than controls. The ethylene production rate in string-harvest tomato with Root-stock No.1 in Area I decreased rapidly to the minimum (0.35 nL·g-1·h-1) 5 d after harvest, significantly lower than its control (1.36 nL·g-1·h-1), and other string-harvest tomatoes in different areas with different rootstocks reached their minimum 15 d after harvest. And, the content of natural antioxidants such as carotenoid, lycopene and ascorbic acid in string-harvest tomatoes increased significantly in the early storage period. Additionally, the string-harvest treatment also inhibited the post-harvest accumulation of soluble sugar and degradation of titratable acid to a certain extent. Finally, string-harvest treatment inhibited the fruit ethylene production, increased carotenoid, lycopene and ascorbic acid level, and delayed post-harvest changes of sugar and acid content, to extend tomato shelf-life and improve commodity quality. This work proposes to explain the physiological mechanisms of the fruit freshness regulation by string-harvest tri-als, provide basal knowledge and evidence for development of new post-harvest technologies, as well as offer guidelines to improving tomato storability and quality, which are meaningful to the tomato production industry.