敌百虫对‘金冠’苹果疏果机制的研究

STUDIES ON THE MECHANSISM OF FRUIT THINNING EFFECT OF DIPTEREX ON ‘GOLDEN DELICIOUS' APPLE

1200ppm敌百虫于盛花后两周对28年生‘金冠’苹果全树喷布,或单涂幼果,都有显著的疏果效应。单喷叶也有一定的疏果作用,但其疏除程度显著小于单涂果的。涂到9年生‘金冠’苹果短果枝莲座叶上或果台副梢中下部成龄叶上的^(14)C-敌百虫,5天后都能明显地运向幼果。涂到幼果上的^(14)C-敌百虫可进入种子,但未见运到其它器官。成龄叶上的^(14)C-敌百虫还可运向果台副梢顶端。乙烯作用抑制剂银离子对敌百虫的疏果效应没有显著影响。萘乙酸与敌百虫混用与相应浓度的敌百虫单用相比,其疏果效应有增加的趋势,但差异不显著。600ppm敌百虫可以部分抵销萘乙酸延迟幼果脱落的作用。文中讨论了敌百虫对‘金冠’苹果疏果的作用部位、乙烯在敌百虫疏果中的作用以及萘乙酸对敌百虫疏果效应的影响,为进一步研究敌百虫的疏果机制提供了线索。

The mechanism of fruit thinning effect of dipterex was studied in several aspects with 'Golden Delicious' apple. The main results are as follows: 1. Localized treatment of either fruits or leaves with 1200 ppm dipterex caused significant fruit abscission, the thinning effect of the former being stronger than the latter. 2. 14C-dipterex applied to the mature spur leaves and bourse shoot leaves was translocated to the actively growing organs, 1, e. the fruit-let and the tip of the bourse, 3-5 days after treatment. 14C-dipterex applied to the fruit was translocated only to the seed. 3. Silver ion, an inhibitor of ethylene action, applied either as silver nitrate (AgNO3) or silver thiosulfat (STS), did not after the effect of dipterex on fruit abscission when applied to entire limbs 24 hours before the dipterex spray. A spray of either AgNO3 or STS alone tended to increase fruit set. 4. 20 ppm naphthaleneacetic acid (NAA) added either to 600 ppm or to 1200 ppm dipterex,applied as a spray two weeks after full bloom, delayed the abscission of young fruits for about one and two weeks respectively in comparison with the corresponding concentration of dipterex without NAA. 5. It is supposed that there are two targets for effective fruit thinning of dipterex, the young fruits themselves and the leaves, that the low concentration of dipterex (600 ppm) might counteract partially the temporary effect of NAA that delays the abscission of young fruits, and that ethylene is not a key factor in the fruit thinning of depterex.