NaCl胁迫下外源壳聚糖对菜用大豆叶绿体 AsA-GSH循环的影响

摘要

为探讨壳聚糖对NaCl胁迫下光合作用的调节机制，采用盆栽试验方法研究了外源壳聚糖对NaCl胁迫下菜用大豆[Glycine max （L．） Merr．]叶绿体内AsA⁃GSH循环的影响。选用菜用大豆主栽品种绿领特早为试验材料，设4个处理：①叶面喷洒清水，根部浇灌营养液（对照）；②叶面喷洒壳聚糖溶液，根部浇灌营养液；③叶面喷洒清水，根部浇灌溶有NaCl的营养液；④叶面喷洒壳聚糖溶液，根部浇灌溶有NaCl的营养液。结果表明，外源壳聚糖阻止了NaCl胁迫下菜用大豆干质量的下降，显著降低了叶绿体H2 O2含量，显著提高了抗坏血酸过氧化物酶（ APX）、单脱氢抗坏血酸还原酶（ MDHAR）、脱氢抗坏血酸还原酶（ DHAR）、谷胱甘肽还原酶（ GR）、谷胱甘肽过氧化物酶（ GPX）活性以及还原型谷胱甘肽（ GSH）含量和胁迫中期还原型抗坏血酸（ AsA）含量。外源壳聚糖对NaCl胁迫下菜用大豆叶绿体内AsA⁃GSH循环产生了显著促进作用，使AsA⁃GSH循环保持较强的活性氧清除能力，这可能是其维持较强光合能力，进而减缓干质量下降的重要原因之一。%In order to investigate the mechanism of photosynthesis regulation by chitosan under NaCl stress, the effects of exogenous chitosan on AsA⁃GSH cycle in the chloroplasts of NaCl⁃stressed vegetable soybean [Glycine max (L.) Merr.] was studied. Four treatments were set for soybean Lutingtezao: (1) foliar water spraying and root watering with mutrient solution (control);(2)foliar chitosan solution spraying and root watering with nutrient solution; (3) foliar water spraying and root watering with NaCl solution;and ( 4) foliar chitosan solution spraying and root watering with NaCl solu⁃tion. The results showed that exogenous chitosan prevented vegetable soybean dry mass from declining, decreased chloroplast H2 O2 content and improved the contents of ascorbate peroxidase ( APX ) , monodehydroascorbate reductase ( MDHAR) , dehydro ascorbic acid reductase ( DHAR) , glutathione reductase ( GR) and glutathione peroxidase ( GPX) ac⁃tivities and dehydroascorbic glutathione ( GSH ) , as well as dehydroascorbic acid ( AsA ) during the mid⁃term of NaCl stress, suggesting that exogenous chitosan facilitated the AsA⁃GSH cycle of vegetable soybean chloroplast, so that the AsA⁃GSH cycle maintained strong activity of reactive oxygen scaven⁃ging, which may be one of the key reasons to keep strong photo⁃ synthetic capacity to prevent dry mass from declining.