Relationships between Lepidosaphes salicina Attack and Contents of Tannins and Phenolic Acids in Leaves of Different Syringa Species and Cultivars Leaves | 柳蛎盾蚧危害与丁香不同种（品种）间叶片单宁、酚酸含量的关系

chinois. 根据柳蛎盾蚧在丁香上的虫口密度,应用聚类分析法将13种（品种）丁香分为高抗类（什锦丁香等7种）、中抗类（西南丁香等3种）、易感类（紫丁香等2种）、高感类（红丁香）。分别在柳蛎盾蚧的未危害期（5月末）、危害盛期（6月末）、危害弱期（7月末）、危害末期（8月末）采集叶片,用香兰素盐酸法、高效液相色谱法测定其内的单宁、酚酸含量,分析丁香叶中单宁、总酚酸含量、酚酸种类等与柳蛎盾蚧危害的关系。结果表明：高抗类丁香叶中的酚酸种类齐全,或者未危害期内总酚酸、单宁含量均显著高于其余种（品种）（P〈0.05）,或者危害盛期单宁、总酚酸增幅均显著高于其余种（增幅为81.75%～888.43%）。中抗类丁香,只在危害盛期总酚酸含量增幅显著高于易感和高感类丁香,单宁含量显著高于易感类丁香。易感和高感类丁香在未危害期单宁和总酚酸含量相对较低,危害盛期单宁或总酚酸含量存在诱导滞后性,酚酸种数只是高抗和中抗类丁香的1/2。此外,一些特定酚酸种类的有无及其含量的多少也与丁香的抗性相关,如：高抗类及中抗类丁香在5―8月均检测到肉桂酸,易感和高感类丁香5―8月均未检测到肉桂酸。总之,丁香中酚酸种类多、总酚酸或单宁含量高,或者其单宁和总酚酸含量能在虫害后迅速升高、增幅大的种类,对柳蛎盾蚧的抗性就强,反之则弱。

anglais. In order to study the resistance mechanism of Syringa spp. against Lepidosaphes salicina, 13 species/ cuhivars of Syringa were categorized into four groups： highly-resistant group （ including 7 species, such as Syringa chinensis） , moderately-resistant group （3 species such as S. emodi） , susceptible group （2 species such as S. oblata） , highly-susceptible group （only 1 species, e.g.S, villosa） , on the basis of the population density of L. salicina on the Syringa spp. by cluster analysis. In the present study, the leaves of the 13 species/cuhivars were sampled separately in pre-infesting period （by the end of May） , peak-infesting period （by the end of June） , weakly-infesting period （by the end of July） and late-infesting period （by the end of August） , the contents of various tannins and phenolic acids of the samples were measured by Vanillin-HC1 and HPLC methods, and the relationships between the leaf extracts and the susceptibility to L. salicina were analyzed. The results showed that in the highly-resistant group, a full range/types of phenolic acids were detected in the uninfected leaves, and the contents of both total phenolic acids and tannins in the uninfected leaves was significantly higher than those species/euhivars in other groups （P 〈 0.05） , the total phenolic acids and tannins in the infected leaves of the highly-resistant group increased by 81.75% -888.43% and the increments were higher than other groups. In the moderately-resistant group, the increment in total phenolic acids contents at the peak- infesting period was significantly higher than that in the highly-susceptible and susceptible groups, and the tannins content was significantly higher than that of susceptible group. The susceptible and highly-susceptible groups had relatively low contents of tannin and total phenolic acids during the pre-infesting period, and delayed induction of tannins and total phenolic acids during the peak-infesting period, and the types of phenolic acids were only a half of the highly- and moderately resistant groups. In addition, the presence or absence of some specific phenolic acids and their contents also had correlation with the resistance of Syringa spp. For example, from May to August, the cinnamic acid was detected in all highly- and moderately-resistant groups, whereas it wasn＇t detected in the susceptible and the highly susceptible groups. In short, the resistance of Syringa spp. against L. salicina was related to the constitutive and induced types and contents of tannins and total phenolic acids. The species containing more types of phenolic acids and high contents of total phenolic acids and tannin, or quickly producing or increasing the contents of tannin or phenolic acids in response to insect attacks, might have a strong resistance potential against L. salicina, and vice versa.