腐皮镰刀菌对不同品种核桃抗性生理指标的影响

为分析腐皮镰刀菌(Fusarium solani)引起的核桃根腐病对寄主抗性生理指标的影响,该研究以铁核桃、绵阳早熟、新疆2号3个核桃品种为材料,研究各品种受腐皮镰刀菌侵染后,不同时期的发病情况以及丙二醛(MDA)、可溶性糖含量以及过氧化物酶(POD)、多酚氧化酶(PPO)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)的动态变化。结果表明：接种病原菌50 d 后,铁核桃100％发病,属高感品种,绵阳早熟和新疆2号发病率分别为23.33％和16.67％,属抗病品种；在50 d 监测范围内,各品种对照组各项叶部生理指标仅出现上下波动且差异不显著；然而,各品种核桃接入腐皮镰刀菌后,可溶性糖含量随时间迅速下降,MDA 含量和 POD 活性总体表现为先上升趋势,SOD、PPO 活性总体则表现为先上升后下降的变化趋势,并且5个指标品种间差异显著,而 CAT 活性变化无规律。相关性分析表明,可溶性糖、MDA 含量、SOD、POD、PPO 活性可以作为核桃品种抗性评价指标。该研究结果为深入研究由腐皮镰刀菌引起的核桃根腐病发病机制以及通过诱导等措施提高其抗性的研究提供了理论基础。

Resistance physiological indexes of different walnut varieties after infected by Fusarium solani

Juglans sigllata, a commercial crop, is widely planted in Liangshan prefecture of Southwest China. Liangshan prefecture is a major traditional growing area of J. sigllata and has an unique advantage for walnut industrial development because of its good conditions of soil, solar-thermal and source of water. Currently there are 2.7 hm² walnut, contributing to an important incomes for farmers. In April 2013, numerous J. sigllata were found infected with the root rot in the Muli County of Liangshan prefecture. Complications include dried leaves, dead brachces, and even death. According to the cultural characteristics, the fungus was primarily identified as Fusarium solani. To analyze the impact of host resistance physiological index of walnut root rot caused by F. solani, in this study, three different walnut varieties including Juglans sigllata, Mianyang walnut and No. 2 of Xinjiang walnut were the samples, and their morbidity situations and six changes of the physiological indexes including MDA, soluble sugar, POD, PPO, SOD and CAT were further detected after inoculated of Fusarium solani respectively. The results showed that the morbidity of Juglans sigllata was up to 100%, and the morbidities of Mianyang walnut and Xinjiang walnut were 23.33% and 16.67%, so it turned out that J. sigllata belonged to highly infected varieties, while the other two were disease-resistant varieties. During the fifty monitoring days, the leaf physiological indexes of the controls showed fluctuated and no obvious difference. But the content of soluble sugar of the experimental group droped rapidly over time, and the content of MDA and POD activities performanced rising trends overall, for SOD and PPO activities, it rose firstly and then droped. Moreover, the differences among the five Indexes of the study were significant while it was irregular to CAT activity. The correlation analysis indicated that the contents of soluble sugar and MDA, the activities of SOD, POD and PPO could be used as the standards to evaluate the resistance abilities of different walnut varieties. This paper provides important references to the study on mechanism of walnut root rot and improvement of resistance abilities.