黄腐酸钾对干旱胁迫下烤烟幼苗活性氧代谢的影响

摘要

To reveal the roles of reactive oxygen metabolism in drought-resistance improvement by fulvic acid potassium in flue-cured tobacco seedlings, the effects of fulvic acid potassium (foliar spraying) on ROS, autioxidant enzyme activities, antioxidant content and MDA content in leaves of flue-cured tobacco with different drought resistance, drought resistant cultivar (honghuadajinyuan) and drought sensitive cultivar (yunyan100) grown under drought stress were investigated by hydroponic experiments. The results showed that the O2– production rate, H2O2 and MDA contents in leaves of flue-cured tobacco seedlings were increased, the activities of SOD, POD and CAT were all significantly enhanced under drought stress, and the content of GSH was significantly increased during the initial period of drought stress, however, the content of AsA was decreased. Under stress conditions, foliar spraying of fulvic acid potassium could effectively enhance the activities of antioxidase and the amount of antioxidants, and decrease the content of superoxide anion, hydrogen peroxide and MDA. Compared with Honghuadajinyuan, there was greater influence on Yunyan100 under drought stress, and fulvic acid potassium could effectively alleviate the stress-induced damage to Yunyan100. These results indicated that fulvic acid potassium could alleviate stress-induced damage to flue-cured tobacco seedlings and improve its drought tolerance through increasing of antioxidants activities/contents.%为揭示黄腐酸钾提高烤烟抗旱能力与体内活性氧代谢之间的关系,以不同抗旱能力的烤烟品种红花大金元和云烟100为试验材料,采用控制水培试验,研究了叶面喷施黄腐酸钾对干旱胁迫下烤烟幼苗叶片中活性氧自由基(ROS)、抗氧化酶活性、抗氧化物质和丙二醛(MDA)含量的影响.结果表明,干旱胁迫处理提高了烤烟幼苗叶片内超氧阴离子(O2?)产生速率、过氧化氢(H2O2)和MDA含量,超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性都有不同程度升高,谷胱甘肽(GSH)含量在胁迫前期也明显升高,而抗坏血酸(AsA)含量降低.黄腐酸钾处理提高了干旱胁迫下SOD、POD和CAT等抗氧化酶活性,同时提高了AsA和GSH含量,降低了O2?产生速率、H2O2和MDA含量.与红花大金元相比,干旱胁迫对云烟100影响较大,且黄腐酸钾对云烟100干旱胁迫伤害的缓解作用较红花大金元大.因此,黄腐酸钾可通过调节抗氧化酶活性与抗氧化物质含量,协同清除ROS,缓解干旱胁迫对烤烟幼苗的伤害.