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作者	单位
刘建新，刘瑞瑞，贾海燕，卜婷，李娜	（甘肃省高校陇东生物资源保护与利用省级重点实验室/陇东学院生命科学与技术学院,甘肃庆阳 745000）

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中文摘要:

为探讨外源H₂S缓解植物盐碱胁迫伤害的生理机制及适宜喷施浓度，以裸燕麦为材料，采用盆栽砂培方法，在根部浇灌50 mmol·L^-1盐碱混合溶液(NaCl︰Na₂SO₄︰NaHCO₃︰Na₂CO₃=12︰8︰9︰1)，同时叶面喷施不同浓度H₂S供体NaHS(0、25、50、100、200、400 μmol·L^-1)，分析了盐碱胁迫条件下外源H₂S对幼苗生长及叶片内源H₂S和光合色素含量、活性氧代谢和渗透物质积累的影响。结果表明，盐碱胁迫下裸燕麦幼苗叶片L-半胱氨酸脱巯基酶活性和H₂S含量均随NaHS喷施浓度的增大而显著提高；喷施25~100 μmol·L^-1 NaHS能够缓解盐碱胁迫对裸燕麦幼苗生长的抑制，喷施200~400 μmol·L^-1 NaHS时幼苗生长受抑加重。喷施25~400 μmol·L^-1 NaHS均不同程度提高了盐碱胁迫下裸燕麦叶片叶绿素、类胡萝卜素和谷胱甘肽含量，对抗坏血酸和可溶性蛋白质含量影响不大，使超氧阴离子、过氧化氢、丙二醛含量和质膜相对透性显著降低或变化不显著；25~200 μmol·L^-1 NaHS处理下超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)活性均不同程度提高，过氧化物酶(POD)活性和游离氨基酸含量显著下降或变化不显著，400 μmol·L^-1 NaHS处理降低了SOD、CAT、APX和POD活性及游离氨基酸、脯氨酸含量；25 μmol·L^-1 NaHS处理显著降低了可溶性糖含量，50~400 μmol·L^-1 NaHS处理的可溶性糖含量不同程度提高。隶属函数综合评价显示，喷施25~200 μmol·L^-1 NaHS提高了盐碱混合胁迫下裸燕麦幼苗的综合评价值(D)，400 μmol·L^-1 NaHS处理的D值显著下降。综合以上结果，喷施适宜浓度NaHS (25~100 μmol·L^-1)可通过调节活性氧代谢和渗透溶质脯氨酸和可溶性糖积累缓解盐碱胁迫造成的氧化伤害和生长抑制，从而增强裸燕麦对盐碱胁迫的耐性。

英文摘要:

In order to explore the physiological mechanism of exogenous H₂S relieving plant saline-alkali stress injury and the appropriate application concentration,seedlings of naked oat(Avena nuda) cultured with potted sand in a solar greenhouse were irrigated with 50 mmol·L^-1 saline-alkali mixed solution(NaCl∶Na₂SO₄∶NaHCO₃∶Na₂CO₃=12︰8︰9︰1),and the leaves were sprayed with different H₂S concentrations(0,25,50,100,200 and 400 μmol·L^-1 NaHS,a exogenous H₂S donor). The seedling growth,endogenous H₂S and photosynthetic pigment contents,reactive oxygen species metabolism and osmoticum accumulation in leaves were measured. The results showed that spraying NaHS increased L-cysteine dethioylase(LCD) activity and H₂S content in leaves of naked oat seedling under saline-alkali stress,and the LCD activity and H₂S content increased with the increase of NaHS concentration. Application of 25-100 μmol·L^-1 NaHS alleviated the inhibition of saline-alkaline stress on the growth of naked oat seedlings,and NaHS of 200-400 μmol·L^-1 aggravated the inhibition of saline-alkali stress on the growth of naked oat seedlings. In addition,the contents of chlorophyll,carotenoid and glutathione in naked oat leaves under saline-alkali stress were increased by spraying 25-400 μmol·L^-1 NaHS to different degrees,but the contents of ascorbic acid and soluble protein did not significantly change,and the contents of superoxide anion,hydrogen peroxide,malondialdehyde and plasma membrane relative permeability were significantly reduced or not significantly different. Under the low NaHS concentrations(25-200 μmol·L^-1),the activities of superoxide dismutase(SOD),catalase(CAT) and ascorbic acid peroxidase(APX) in leaves under saline-alkali stress all increased to different degrees. However,the peroxidase(POD) activity and free amino acid content decreased significantly or the difference was not significant. Under the high NaHS concentration(400 μmol·L^-1),the activities of SOD,CAT,APX,POD and the contents of free amino acid and proline in leaves under saline-alkali stress decreased significantly. 25 μmol·L^-1 NaHS treatment significantly reduced the content of soluble sugar in the leaves of naked oats under saline-alkali stress,and 50-400 μmol·L^-1 NaHS treatment increased the content of soluble sugar in varying degrees. The comprehensive evaluation of membership function showed that spraying 25-200 μmol·L^-1 NaHS increased the comprehensive evaluation value(D) of naked oat seedlings under saline-alkali mixed stress,and the D value of 400 μmol·L^-1 NaHS decreased significantly. The above results showed that 25-100 μmol·L^-1 NaHS alleviated the oxidative damage and growth inhibition of naked oat under salt-alkali stress by regulating the metabolism of active oxygen and the accumulation of osmotic regulator such as proline and soluble sugar,so as to enhance the tolerance of naked oat to salt-alkali stress.

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