外源水杨酸对高温胁迫下金莲花幼苗生理及电阻抗参数的影响

为解决金莲花幼苗在北方低海拔地区越夏过程中生长不良的问题,研究喷施水杨酸对高温胁迫下金莲花幼苗生理及电阻抗参数的影响,为提高金莲花的耐热性提供理论依据。以金莲花幼苗为试验材料,外源水杨酸(SA)设置4个浓度梯度(0.5、1.0、1.5、2.0 mmol·L-1),喷施处理后置于人工气候箱内进行昼38℃/夜30℃的高温胁迫试验。结果表明:喷施0.5~1.0 mmol·L-1水杨酸能有效降低金莲花幼苗的热害指数、相对电导率和丙二醛(MDA)含量,缓解叶绿素降解、显著提高可溶性糖含量、游离脯氨酸含量以及超氧化物歧化酶(SOD)活性,其中以1.0 mmol·L-1的水杨酸(SA)处理效果最好,JP2]说明喷施适宜浓度的SA可以提高金莲花的耐热性,从而缓解高温伤害。相关性分析表明,热害指数与相对电导率呈极显著正相关(P<0.01),与叶绿素总量、可溶性糖含量胞外电阻率(r e)呈显著负相关(P<0.05),胞内电阻率(r i)与Pro含量呈显著正相关,弛豫时间(τ)与Pro含量和SOD活性呈极显著正相关,因此胞外电阻率、胞内电阻率和弛豫时间等电阻抗参数可作为金莲花对高温逆境反应的评价指标。JP]

Effects of Exogenous Salicylic Acid on Physiological and Electrical Impedance Parameters of Trollius chinensis Seedlings under High Temperature Stress

In order to solve the problem of poor growth of Trollius chinensis seedlings during summer in low altitude areas of North China, the effects of salicylic acid spraying on physiological and electrical impedance parameters of T.chinensis seedlings under high temperature stress were studied for improving the heat resistance of T.chinensis. With T.chinensis seedlings as experimental materials, exogenous salicylic acid(SA) was sprayed with four concentration gradients(0.5, 1.0, 1.5 and 2.0 mmol·L^-1) and placed in an artificial climate chamber for high temperature stress test at 38℃ on day and 30℃ at night. The results showed that spraying 0.5-1.0 mmol·L^-1 salicylic acid could effectively reduce the heat injury index, relative conductivity and malondialdehyde(MDA) content of T.chinensis seedlings, alleviating chlorophyll degradation, significantly increase soluble sugar content, free proline content and superoxide dismutase(SOD) activity, among which 1.0 mmol·L^-1 salicylic acid(SA) had the best treatment effect, indicating that spraying SA with appropriate concentration could improve the heat resistance of T.chinensis seedlings, so as to alleviate the high temperature damage. The correlation analysis of each index showed that the heat injury index was positively extremely correlated with relative conductivity, negatively significantly correlated with total chlorophyll content, soluble sugar content and extracellular resistivity(r_e)(P<0.05), positively significantly correlated with intracellular resistivity(r_i) and Pro content, and positively significantly correlated with relaxation time(τ) and Pro content and SOD activity. Therefore, the resistance parameters such as extracellular resistivity, intracellular resistivity and relaxation time that can be used as an evaluation index of response of T.chinensis to high temperature stress.