Stopar Matej, Bolcina Uros, Vanzo Andreja, Vrhovsek Urska
Agricultural Institute of Slovenia, Hacquetova 17, 1000 Ljubljana, Slovenia.
J Agric Food Chem. 2002 Mar 13;50(6):1643-6. doi: 10.1021/jf011018b.
The influence of crop load on fruit quality was investigated on 7-year-old slender spindle cv. Jonagold/M.9 apple trees. In mid June five different crop loads per tree were prepared by reducing the fruit number to average 30, 59, 104, 123, and 157 fruits per crown. The fruit from low-cropping trees had more red blush, a higher percentage of soluble solids in fruit flesh, and better flesh firmness in comparison to fruit from high-cropping trees. As the crop load decreased, the concentration of all phenolic compounds in the fruit samples (cortex plus skin) increased; concentrations of the most important individual fruit phenolics were also higher. When crop load fell from 157 to 30 fruits per crown, total polyphenols increased from an average of 1300 to 1680 mg/kg of fruit fresh weight (FW) (+29%), low molecular weight polyphenols increased from 1140 to 1570 mg/kg of FW (+38%), and high molecular weight polyphenols increased from 1740 to 2070 mg/kg of FW (+19%). The average increases in single polyphenols were even greater: chlorogenic acid (+82%); 4'-p-coumaroylquinic acid (+22%); catechin (+178%); and epicatechin (+71%). Ascorbic acid was not significantly dependent on crop load.
在7年生细长纺锤形乔纳金/M.9苹果树上研究了负载量对果实品质的影响。6月中旬，通过将每株树的果实数量分别减少至平均每树冠30、59、104、123和157个果实，制备了五种不同的负载量。与高负载量树的果实相比，低负载量树的果实红晕更多，果肉中可溶性固形物百分比更高，果肉硬度也更好。随着负载量降低，果实样品（皮层加果皮）中所有酚类化合物的浓度均升高；最重要的单一果实酚类物质的浓度也更高。当负载量从每树冠157个果实降至30个果实时，总多酚含量从平均每千克果实鲜重（FW）1300毫克增至1680毫克（增加29%），低分子量多酚从1140毫克/千克FW增至1570毫克/千克FW（增加38%），高分子量多酚从1740毫克/千克FW增至2070毫克/千克FW（增加19%）。单一多酚的平均增幅更大：绿原酸（增加82%）；4'-对香豆酰奎尼酸（增加22%）；儿茶素（增加178%）；表儿茶素（增加71%）。抗坏血酸与负载量无显著相关性。
