苹果绵蚜对不同苹果品种春梢生长期生理指标的影响

为了筛选培育对苹果绵蚜(Eriosoma lanigerum Hausmann)的抗性品种,实现持续有效治理苹果绵蚜的目的,通过测定红富士、金帅、昭锦108、秦冠、红将军等5种不同苹果品种春梢生长期被苹果绵蚜危害前后枝条内可溶性糖、蛋白质、游离氨基酸、总酚含量以及防御性酶的活性变化,探讨苹果生理指标与抗蚜性的关系。结果表明,被害后可溶性糖含量除红将军外均有所上升,其中红富士上升达13.7%;蛋白质含量除红富士外均有所降低;氨基酸含量均有所上升,其中红将军变化明显,变化率达68.8%。酚类物质是一种重要的抗蚜物质,红富士、昭锦108、秦冠被害后总酚含量均升高,其中昭锦108、秦冠中总酚含量上升率约为红富士的2倍。红富士品种正常枝条内超氧化物歧化酶(Superoxide Dismutase,SOD)、多酚氧化酶(Polyphenol Oxidase,PPO)、过氧化物酶(Peroxidase,POD)以及过氧化氢酶(Catalase,CAT)活性均显著低于昭锦108,被害后各苹果枝条SOD活性均出现上升趋势,除红将军的PPO、POD活性降低外,其他品种均升高;金帅、红富士的CAT活性上升明显,分别为110.8%、45.5%。植物的防御性酶与其抗虫性有密切关系,苹果春梢生长期对苹果绵蚜的抗性与苹果体内的可溶性糖、游离氨基酸、SOD、PPO、POD以及CAT活性均有关,而且不同苹果品种被害后生理指标的变化也与其抗蚜性有一定关系。

Effects of Eriosoma lanigerum (Hausmann) on physiological indices of different apple cultivars

The woolly apple aphid, Eriosoma lanigerum Hausmann, is native to eastern North America. It threatens the survival of apple trees by infesting shoots and roots, ultimately resulting in decreased apple production. The woolly apple aphid has spread to most apple-growing regions of the world and is now an important pest in apple production areas. The following control methods have been tested: chemical control, biological control, agrotechnical control and host plant resistance. However, chemical control causes resistance, residue and resurgence (the "3R" problem), biological control is constrained by climate, and agrotechnical control wastes time and resources. Consequently, host plant resistance seems optimal because it is safe, effective and economically viable. Some studies have shown that physiological indices can indicate the insect resistance of a plant. To reveal the relationship between physiological indices in apples and resistance to woolly apple aphid, we studied changes in soluble sugar, protein, free amino acids, total phenolic compounds and defense enzymatic activities in five apple cultivars damaged by E. lanigerum. The five apple cultivars studied were Red Fuji, Golden Delicious, Zhaojin 108, Qinguan and Red General. Red Fuji is the most sensitive cultivar and Qinguan the most resistant. Golden Delicious, Zhaojin 108 and Red General demonstrate average resistance. To examine physiological indices, one-year-old injured branches from the lower parts of the trees were clipped and frozen with Drikold. Undamaged branches were treated using the same method as for the control group. Results showed that the soluble sugar contents increased in damaged branches, except in those of Red General trees. Soluble sugar contents in Red Fuji increased by 13.7%. Protein contents in the four cultivars besides Red Fuji decreased. Amino acid contents increased in all five cultivars, increasing by 68.8% in Red General. Total phenolic compound is an important defensive substance against aphids. The total phenolic compound was increased in Red Fuji, Zhaojin 108 and Qinguan after damage by woolly apple aphid, and the rate of change of total phenolic compound in Zhaojin 108 and Qinguan was about twice that of Red Fuji. The Superoxide Dismutase (SOD), Peroxidase (POD), Polyphenol Oxidase (PPO) and Catalase (CAT) activities in Red Fuji were markedly lower than that in Zhaojin 108. The SOD activity was increased in all five cultivars. Activities of PPO and POD were increased in all cultivars except Red General. The activity of CAT in Golden Delicious and Fuji increased by 110.8% and 45.5%, respectively. Plant resistance to pests is closely linked with the defensive enzymes exhibited by the plant. It is suggested that the contents of soluble sugar, amino acids and the activities of SOD, POD, PPO and CAT affect host selection by woolly apple aphids. Changes in physiological indices in different apple cultivars are associated with resistance to woolly apple aphid.