两种麻疯树苗对盐胁迫的生理生态响应

研究两种不同基因型麻疯树苗(南油2、3号)在不同NaCl浓度下生理生态响应特征,并比较不同基因型麻疯树苗的耐盐差异性。结果表明:①用25、50 mmo.lL-1NaCl处理,南油2号全株干重与对照无显著差异,而南油3号全株干重比对照显著降低。用100 mmol.L-1l或以上浓度的NaCl处理,随着盐度增加,两种树苗全株干重皆比对照显著降低,且3号苗降低的幅度大于2号苗。②在用200 mmol.L-1或以下浓度的NaCl处理,南油2、3号叶片相对含水量(RWC)皆与对照无显著差异,而在用300 mmol.L-1NaCl处理,则分别比对照显著降低5%和8%。③用25、50 mmol.L-1NaCl处理,南油2号可溶性糖(SS)含量比对照显著降低,3号与对照无显著差异;用200、300 mmo.lL-1NaCl处理后,两者SS含量均比对照显著降低。同时,2号苗可溶性蛋白(SP)含量比对照显著增加,3号苗SP含量与对照无显著差异。④随着盐度增加,南油2号苗超氧化物歧化酶(SOD)活性先增加后降低。用300 mmol.L-1NaCl处理,比对照显著降低。随着盐度增加,3号苗的SOD活性递减,皆显著低于对照。用25、50 mmo.lL-1NaCl处理,两种树苗的过氧化物酶(POD)活性与对照无显著差异。随着盐度增加,2号苗的POD活性比对照显著增加,而3号苗比对照显著降低。用25、50 mmo.lL-1NaCl处理,两种树苗的过氧化氢酶(CAT)活性皆比对照显著增加,且随着盐度增加,其变化趋势如SOD活性。结果表明,麻疯树幼苗具有较好的耐盐性,且南油2号比南油3号具有更高的耐盐性,因为前者具有更高的保护酶活性、叶片保水能力和叶片SP含量。

Response characteristics of physiology and ecology to salt stresses in two varieties of Jatropha curcas L. seedlings

Nanyou 2 and Nanyou 3 are two cultivars of barbadosnut (Jatropha curcas L.) with different genotypes. Physiological and ecological responses of these two cultivars to salt stress were studied by comparing their tolerances to various concentrations of NaCl. When the seedlings were exposed to NaCl at 25 and 50 mmol?L-1, Nanyou 2 showed no change while Nanyou 3 decreased significantly in total dry weight. When treated with NaCl at 100 mmol?L-1 or higher concentrations, the total dry weight of seedlings of both cultivars decreased significantly, and Nanyou 3 decreased to a greater extent than Nanyou 2 did. Relative water contents of seedling leaves showed no changes upon treatment with NaCl at 200mmol?L-1 or lower concentrations, but a significant decrease by 5% and 8% in Nanyou 2 and Nanyou 3, respectively, upon treatment with NaCl at 300mmol?L-1. When treated with NaCl at 25 and 50 mmol?L-1, Nanyou 2 decreased significantly whereas Nanyou 3 showed no change in the soluble sugar contents. As the NaCl concentration increased to 200 and 300 mmol?L-1, the soluble sugar contents of both cultivars decreased significantly. Meanwhile, Nanyou 2 had a significant increase while Nanyou 3 showed no change in the soluble protein contents. The SOD activity of Nanyou 2 displayed an increase-decrease curve as the NaCl concentrations increased, and, upon treatment with NaCl at 300mmol?L-1, it was significantly lower than the control plants. The SOD activity of Nanyou 3 decreased steadily as salt concentrations increased and was significantly lower than the control plants in all treatments. The POD activities of both cultivars showed no differences with the control plants as treated with 25 and 50 mmol?L-1 of NaCl. As the NaCl concentrations increased, POD activity of Nanyou 2 increased and that of Nanyou 3 decrease significantly as compared to corresponding controls. The CAT activities of both cultivars increased significantly when treated with NaCl at 25 and 50 mmol?L-1, and then showed similar trend as the SOD activities did in both cultivars respectively as the salt concentrations increased. These results suggested that barbadosnut seedlings were salt tolerant, and the Nanyou 2 was more tolerant than Nanyou 3, mainly due to its higher protective enzyme activities, ability to maintain higher leaf water contents and higher soluble protein contents upon exposure to salt stress.