张爱华+马文丽+雷锋杰+安宁波+张欣欣+刘志庆+张连学

[摘要] 该实验采用平板对峙培养法和孢子悬滴萌发法探讨了人参黑斑菌对精氨酸、谷氨酸、天冬氨酸以及苏氨酸在不同条件下化学趋向性响应。结果显示，人参黑斑菌对4种氨基酸化学趋向性响应的最优培养温度均为25 ℃，不同质量浓度和pH的培养条件下人参黑斑菌对4种氨基酸化学趋向性响应有所差异，其中精氨酸、谷氨酸及苏氨酸在质量浓度为2 mg·L^-1，pH 7，天冬氨酸在20 mg·L^-1，pH 6时，化学趋向性均达到最强，其趋化率分别为1.24，1.38，1.27，1.31；生长速率分别为0.451 0，0.353 0，0.381 3，0.228 8；孢子萌发率分别为57.33%，63%，56.67%，58%；菌丝干重分别为372.9，348.5，314.4，390.2 mg·L^-1。氨基酸作为人参根系分泌物中的重要物质对人参黑斑病菌表现出了高效的趋化性效应，有的甚至出现了高浓度抑制的现象。

[关键词] 人参黑斑病菌；根系分泌物；氨基酸；化学趋向性

[Abstract] Plate assay and spore germination method were used to study the chemotaxis response of Alternaria panax to arginine，glutamic acid，aspartic acid and threonine. The result showed that the optimum temperature of A. panax chemotaxis response to four amino acids were all 25 ℃. And chemotaxis responses of A. panax were different under conditions of different concentration and pH value. The chemotaxin reached to the highest under the condition of 2 mg·L^-1 and pH value was 7 for arginine，glutamic acid and threonine while 20 mg·L^-1 and pH value was 6 for aspartic acid . The data of chemotactic migration index （CMI） were 1.24，1.38，1.27，1.31 and chemotactic growth rates（CGR） were 0.451 0，0.353 0，0.381 3，0.228 8 and spores germination rates（SGR） were 57.33%，63%，56.67%，58% and the dry weight of mycelial （DWM） were 372.9，348.5，314.4，390.2 mg·L^-1 respectively. It indicated that the low and middle concentration of amino acid had significant promoting effect on chemotaxis response of A. panax. As important substances generated in ginseng root，amino acids exhibited an efficient chemotactic effect on A. panax，and some even show inhibition effect under high concentration .

[Key words] Alternaria panax；root exudates；amino acid；chemotaxis

人參Panax ginseng C.A.Mey.为五加科草本植物，享有“百草之王”的美誉。长期以来，由于原始生态环境的改变以及不断的过度采挖致使我国野生人参资源匮乏。近年，我国人参栽培产业迅猛发展，人工栽培面积逐年扩大，栽培种类繁，但由于生长环境的改变以及人参病害的发生和流行导致人参产量大幅度下降，其中人参黑斑病菌是发生最普遍，危害最严重[1]，更是人参规范化生产的重要病害。根系分泌物是植物在生长的过程当中产生的并经根的不同部位向外界环境分泌的物质[2]，此类物质作为趋化基质在植物与真菌之间起着调节作用[3-4]，而这一趋化性运动是病原真菌对不同趋化物质浓度、温度、pH做出的反应，使趋向有益刺激，逃避有害刺激[5-6]，并且与植物的生长有很密切的关系。……