NaCl处理对曼陀罗幼苗生长、光合、离子积累及抗氧化系统的影响

Effects of NaCl Treatment on Seedling Growth, Photosynthesis, Ion Accumulation and Antioxidant System of Datura stramonium

通过测定曼(Datura stramonium L.)陀罗鲜质量、干质量、叶绿素质量分数、光合参数、Na^+和K^+质量摩尔浓度、脂肪酸质量分数、丙二醛(MDA)质量摩尔浓度、超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)和谷胱甘肽还原酶(GR)等抗氧化酶的活性,研究曼陀罗在盐渍环境的生理适应机制及耐盐适应性。结果表明:NaCl处理后,曼陀罗幼苗鲜质量、干质量、叶绿素a、叶绿素b、总叶绿素质量分数显著降低。随着盐胁迫的加剧,曼陀罗幼苗叶片净光合速率(Pn)逐渐下降,T1(土壤NaCl质量分数为0.15%)处理Pn降低幅度较小,T2(土壤NaCl质量分数为0.40%)和T3(土壤NaCl质量分数为0.60%)处理Pn显著降低,分别比对照降低33.54%和41.59%。NaCl处理使曼陀罗地上部分和根部Na^+质量摩尔浓度明显增加,根部比地上部分积累更多的Na^+。随着盐胁迫的加剧,地上部分的K^+质量摩尔浓度逐渐降低,根部K^+质量摩尔浓度未受到显著影响。NaCl处理后,曼陀罗叶片3种不饱和脂肪酸质量分数总体呈上升趋势,亚麻酸上升幅度最大,各处理分别比对照增加11.03%、20.17%和27.58%。T1处理曼陀罗受到的氧化伤害较轻,表现为较低的MDA质量摩尔浓度;T2和T3处理MDA质量摩尔浓度显著升高,氧化伤害明显加重。NaCl处理后,除GR外,SOD、POD、CAT和APX均明显增加。综上,曼陀罗通过调整Na+在根部与地上部分的积累比例,提高不饱和脂肪酸质量分数,有效调动抗氧化防御体系,共同抵御盐胁迫造成的伤害。曼陀罗具有一定的耐盐性,可作为盐碱地区重点开发的优质能源植物资源。

Fresh weight, dry weight, chlorophyll content, photosynthetic parameters, the molar concentrations of Na^+ and K^+, the fatty acid contents, the molar concentration of malondialdehyde(MDA), and the activities of antioxidant enzymes including superoxide dismutase(SOD), peroxidase(POD), catalase(CAT), ascorbate peroxidase(APX) and glutathione reductase(GR) were determined to study the physiological response mechanism and salt tolerance of Datura stramonium L. under the saline environment. The results showed that fresh weight, dry weight, the contents of chlorophyll a, chlorophyll b and total chlorophyll were significantly reduced after NaCl treatment. With the increase of salt stress, net photosynthetic rate(Pn) of the D. stramonium seedlings decreased gradually, the decrease under T1 treatment was lower, while that under T2 and T3 treatment decreased significantly, increased by 33.54% and 41.59% compared with that in the control group, respectively. NaCl treatment resulted in a significant increase in the molar concentration of Na^+ in the aerial parts and the roots of D. stramonium seedlings, and the roots accumulated more Na^+ than the aerial parts. With the increase of salt stress, the molar concentration of K^+ in the aerial parts was gradually decreased, and that of K^+ in the roots was not significantly affected. Under the treatment of NaCl, the contents of three unsaturated fatty acids in the leaves of D. stramonium increased, especially the increase of linolenic acid, increased by 11.03%, 20.17% and 27.58%, respectively. The molar concentration of MDA under the treatment of T2 and T3 increased significantly. Under NaCl treatment, SOD, POD, CAT and APX increased significantly excluding GR. In conclusion, the accumulation ratio of Na+ between the roots and the aerial parts, the amount of unsaturated fatty acids, and the operating efficiency of the antioxidant defense system were improved and adjusted to resist the damage caused by salt stress. D. stramonium has a certain salt tolerance, and can be used as a high-quality energy plant resource for the key development in saline-alkali areas.