环渤海湾地区连作苹果园土壤中酚酸类物质变化

分析了山东昌邑、栖霞、蓬莱,辽宁大连、抚宁、绥远,河北昌黎、青县等地苹果园连作土壤中酚酸物质的组成和含量,结果表明:连作障碍发生的苹果园土壤中酚酸类物质的组成和含量在不同地区、不同土层厚度间存在显著差异。苹果园土壤中酚酸类物质的含量从春季到秋季随时间的延长逐渐减少,但过程缓慢。且非连作园土壤中酚酸类物质含量显著少于连作土。连作土壤中酚酸物质的组成和含量在不同季节间差异显著,尤其春季土壤中酚酸物质的种类与夏季和秋季显著不同。这可能是因为植物在不同季节分泌的酚酸类物质种类和含量有差别.不同土层中酚酸物质的分布因季节不同而有显著差异。夏季土壤中酚酸物质主要分布在浅层土壤中,而秋季则主要分布在深层土壤中。这可能是由于浇水等果园管理措施和自然降水对土壤中的酚酸物质产生的淋溶作用,使得大量的酚酸物质向深层土壤运动,最终造成了秋季果园连作土中随土层加深而酚酸物质含量增加的现象。不同地区苹果园连作土中,对羟基苯甲酸、(+)-儿茶素、咖啡酸、阿魏酸含量与非连作土无显著差异,而焦性没食子酸、绿原酸和根皮苷显著高于非连作土。焦性没食子酸、绿原酸和根皮苷可能是引起山东、辽宁、河北地区苹果园连作障碍的关键酚酸物质。

Changes of phenolic acids in the soil of replanted apple orchards surrounding Bohai Gulf

Apple replant disease (ARD) is widely found in the most, if not all, apple production region through the world. It is a complex soil-borne disease syndrome that affects tree growth, suppresses the yield and quality of apple fruits when orchards are replanted. The causes of replant problem of apple trees are considered as a combination of abiotic and biotic factors, including phenolic acids, fungi, bacteria, actinomycetes and nematodes etc. At present, there is a bulk of research conclusions on replant disease and some of them suggest that phenolic acids are closely link to replant disease. Meanwhile, however, few references are referred to the changes in phenolic acids in the soils of apple replant orchard. In view of it, the composition and content of phenolic acids in the soils of apple orchards were tested in several regions around Bohai Bay, including Changyi, Qixia, Penglai of Shandong province and Dalian, Funing, Suiyuan of Liaoning province as well as Changli and Qingxian of Hebei province. The results showed that the composition and content of phenolic acids in apple orchards infested with replant diseases varied with regions and soil thickness. The contents of phenolic acids gradually decreased from spring to fall in apple orchard soils. However, the contents of phenolic acids in non-replant soils were much lower than those of replant soils. In replant soils the composition and content of phenolic acids remarkably differed in diverse seasons, especially in spring, while the types of phenolic acids were markedly different from the summer and fall. The possible reason on the difference was that the composition and content of phenolic acids secreted by plants in different seasons varied. Besides, the distribution of phenolic acids in different soil layers varied with seasons. In summer the phenolic acids mainly distributed in shallow soil. In contrast, it mostly relocalized to the deep layer of soil in autumn. The possible reason on this change was that artificial irrigation and natural precipitation resulted in an eluviation of the phenolic acids in soils, which dispersed large numbers of phenolic acids to move to the deep layer of soil. As a result, phenolic acids content increased with the soil depth in replant orchard soil in autumn. There were no significant differences in contents of p-hydroxybenzoic acid, catechin, caffeic acid and ferulic acid between the replant and non-replant soils from different regions. Furthermore, contents of pyrogallic acid, chlorogenic acid and phlorizin were much higher in replant soils than those in non-replant soils. Taken together, pyrogallic acid, chlorogenic acid and phlorizin were summarized to be the key phenolic acids that brought about apple replant disease in Shandong, Liaoning and Hebei.