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为明确干旱胁迫下外源硫化氢(H2S)对植物幼苗的缓解作用,以玉米自交系郑58为试验材料,研究了不同浓度(0、0.3、0.6、0.9、1.2及1.5 mmol·L-1)的H2S供体硫氢化钠(Na HS)对15%PEG模拟干旱胁迫下玉米种子萌发的影响,并以筛选到的最佳Na HS浓度对幼苗进行叶面喷施,研究其对幼苗叶片抗氧化酶活性、抗氧化剂含量、游离脯氨酸(Pro)和活性氧(ROS)的积累特征及膜质过氧化水平的影响。结果表明,不同浓度的Na HS处理在一定程度上提高了干旱胁迫下玉米种子的发芽势、发芽率及幼苗的生物量,其中以0.6 mmol·L-1的Na HS处理效果最佳。叶面喷施0.6 mmol·L-1Na HS溶液显著增强了叶片中超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)及抗坏血酸过氧化物酶(APX)活性,提高了叶片中抗坏血酸(As A)和谷胱甘肽(GSH)的含量。同时,外源H2S处理增强了玉米叶片中△1-吡咯啉-5-羧酸合成酶(P5CS)的活性,提高了叶片中游离Pro含量,显著降低了叶片中过氧化氢(H2O2)及丙二醛(MDA)含量。综上,外源H2S处理通过提高幼苗的抗氧化水平,减少干旱胁迫对玉米叶片造成的氧化损伤,在一定程度上提高了玉米幼苗对干旱胁迫的适应能力。本研究为进一步探索H2S缓解玉米干旱胁迫的机理提供了理论依据。
In order to clarify the alleviating effect of exogenous hydrogen sulfide (H2S) on plant seedlings under drought stress, the effects of different concentrations (0, 0.3, 0.6, 0.9, 1.2 and 1.5 mmol·L- 1) H2S donor sodium hydrosulfide (Na HS) on seed germination of 15% PEG simulated drought stress in maize, and the best Na HS concentration screened the leaves of young seedlings sprayed to study the seedling leaves Antioxidant enzyme activity, antioxidant enzyme activities, accumulation of free proline (Pro) and reactive oxygen species (ROS) and the effect of membrane lipid peroxidation. The results showed that Na HS treatment at different concentrations increased the germination potential, germination rate and seedling biomass of maize seeds under drought stress, of which the treatment with 0.6 mmol·L -1 Na HS was the best. Foliar application of 0.6 mmol·L-1Na HS significantly enhanced the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) , Increased the content of As A and GSH in leaves. At the same time, exogenous H2S treatment enhanced the activity of △ 1-pyrroline-5-carboxylic acid synthase (P5CS) in maize leaves, increased the content of free Pro in leaves and significantly reduced the contents of hydrogen peroxide (H2O2) and Dialdehyde (MDA) content. In conclusion, exogenous H2S treatment can reduce the oxidative damage caused by drought stress on maize leaves by increasing the anti-oxidative level of seedlings, and to some extent, improve the adaptability of maize seedlings to drought stress. This study provides a theoretical basis for further exploring the mechanism of H2S alleviating drought stress in maize.