外源硫化氢对PEG模拟干旱胁迫下玉米种子萌发及幼苗生长的影响

Effects of Exogenous Hydrogen Sulfide on Seed Germination and Seedling Growth Under PEG Stimulated Drought Stress in Maize

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。

To investigate the alleviation effects of exogenous hydrogen sulfide（ H2S） on maize seeding growth under drought stress,maize inbred line Zheng 58 was employed and treated under nutrient solution with different concentrations（ 0,0.3,0.6,0.9,1.2 and 1.5 mmol·L- 1） sodium hydrosulfide（ Na HS） process maize seedlings under 15% PEG simulated drought stress.The optimal concentration of Na HS were also used to spray on the leaves of seedling,and to study the antioxidant enzyme activities,antioxidant content,free proline accumulation,reactive oxygen species（ ROS）accumulation,and membranous peroxide level on seedlings.According to the results,under the drought stress,exogenous H2 S treatment significantly improved the maize seed germination activity,germination rate and seedling biomass to some extent.After spraying 0.6 mmol·L- 1Na HS on the leaves,the antioxidant enzyme activities including superoxide dismutase（ SOD）,peroxidase（ POD）,catalase（ CAT） and ascorbic acid peroxidase（ APX）,and the content of ascorbic acid（ ASA） and glutathione（ GSH） were increased.Moreover,the delta 1- pyrroline- 5-carboxylic acid synthetase（ P5CS） activity and the free proline（ Pro） content in the leaves were also increased.However,hydrogen peroxide（ H2O2） and malondialdehyde（ MDA） contents had a significantly drop.These illustrated that the exogenous H2 S regulated the antioxidant levels in leaves to reduce oxidative damage on maize seedling during drought stress that improved the maize seedling adaptability to drought stress.This study provided the basis for the further study of H2 S function on maize drought stress response mechanism.