Studies on fruit ripening on the vine and after harvest in kiwifruit

研究了乙烯利对“海沃德”猕猴桃（Actinidia deliciosa）果实成熟的影响，结果表明，在商品采收前约1周施用200 ppm乙烯利（50%乙醇溶解），处理4周和3周后果实可食。另一方面，50%乙醇的应用是无效的果实成熟。在商品采收前3周用不同浓度乙烯利处理，50和100ppm处理对果实成熟无效，500ppm处理比200ppm处理促进果实成熟，第二年用200ppm乙烯利处理后，果实不再象前一年那样成熟。我们将这种差异归因于今年实验期间气温较低，日照时间较短。由以上结果推测，施用乙烯利后的气温和太阳辐射持续时间对葡萄藤上猕猴桃的成熟有强烈影响，因此详细研究了较高浓度乙烯利对葡萄藤上猕猴桃成熟的影响。当500 ppm的乙烯利施加约3周前商业收获，果实变得可食用约2周后处理。但果实在处理后约2周开始强烈下降。这些治疗效果并不随年份而变化。500 ppm处理能有效地促进果实的乙烯合成，但乙烯利处理后果实立即开始成熟，因此乙烯利促进果实成熟的作用主要是乙烯的释放，而500 ppm乙烯利与100 ppm GA_3处理后果实可食，并能有效地防止落果。看来这种施用方法对葡萄果实成熟的效果更稳定和有效。

Effects of ethephon application on the fruit ripening of 'Hayward' kiwifruit (Actinidia deliciosa) on the vine were investigated.When 200 ppm ethephon (dissolved with 50% ethanol) was applied at approximately 1-week interval prior to commercial harvest, the 4- and 3-week treatments made the fruits edible. On the other hand, 50% ethanol application was ineffective on fruit ripening. When ethephon was applied at various concentrations 3 weeks before commercial harvest, the 50 and 100 ppm treatments were ineffective on fruit ripening, whereas the 500 ppm treatment hastened fruit ripening more than 200 ppm treatment.In the next year, when fruits were treated with 200 ppm ethephon, they did not ripen as they did in the previous year. We attribute the difference to the lower air temperature and shorter duration of sunshine during this year experiments. From above results, we postulated that the air temperature and duration of solar radiation after ethephon application strongly affect the kiwifruit ripening on the vine.So effects of higher concentration of ethephon on the fruit ripening on the vine were investigated in detail. When 500 ppm of ethephon was applied about 3 weeks before commercial harvest, the fruit became edible about 2 weeks after treatment. But the fruits started to drop strongly about 2 weeks after treatment. And these effects of the treatment did not varied with the year. 500 ppm treatment effectively induced ethylene synthesis by fruits, but it seems that fruit ripening on the vine by the ethephon application is mainly promoted by ethylene produced from ethephon, because fruits immediately started to ripe after treatment.On the other hand, when 500 ppm ethephon was applied with 100 ppm GA_3, the fruit became edible and fruit drop was strongly prevented. It seems that effects of this application method are more stable and effective on the fruit ripening on the vine.