外源褪黑素对高温胁迫下茄子幼苗光合及抗氧化特性的影响

以紫红长茄为材料,采用营养钵种植法,设4种不同浓度的褪黑素(MT)溶液(50、100、150、200μmol/L),以清水处理为对照处理,喷施茄子幼苗叶片,再将茄子幼苗进行高温胁迫,通过测定茄子幼苗的光合参数以及POD、SOD等生理生化指标,研究外源褪黑素对高温胁迫下茄子幼苗的光合作用及抗氧化特性的影响。结果表明:喷施MT能有效提高高温胁迫下茄子幼苗叶片中光合色素含量及光合能力,当MT浓度为150μmol/L时,茄子叶片的叶绿素含量和净光合速率均达到最大值,分别为3.69 mg/g和12.14μmol/(m2·s),与对照相比,差异显著;喷施各浓度的MT均能显著提高茄子幼苗抗氧化酶POD、SOD、CAT活性,当MT浓度为150μmol/L时,SOD、CAT活性最高,分别为256.31、41.80 U/g,且与MT浓度为200μmol/L时的SOD、CAT活性差异无统计学意义;喷施各浓度的MT均能显著降低MDA含量,当MT浓度为150μmol/L时,MDA含量最低,为16.71 nmol/g。喷施外源MT能提高茄子对高温胁迫的抵抗力,且浓度为150μmol/L时效果较好。

Effects of exogenous melatonin on photosynthesis and antioxidant activity of eggplant seedlings under high temperature stress

In this study, the eggplant(Solanum melongenaL.) seedlings planted in the nutritive soil cup were placed in high temperature condition for 24 hours after the leaves were sprayed by four different concentrations of melatonin solution( by water as control), then the indexes of the photosynthetic parameters, the activities of SOD, POD and CAT and the content of MDA were measured to study the effect of exogenous melatonin (MT) on photosynthesis and antioxidant properties of eggplant seedlings under high temperature stress. The results showed that foliar application of MT could effectively increase photosynthetic capacity and antioxidant properties of eggplant seedlings under high temperature stress. Compared with the other MT concentration treatments and the control, 150μmol/L had the greatest effect on the contents of chlorophyll (3.69 mg/g) and net photosynthetic rate (12.14μmol/m2·s), the activities of SOD(256.31 U/g) and CAT(41.80 U/g), the content of MDA(16.71 nmol/g). The contents of chlorophyll and net photosynthetic rate of 150μmol/L were significant higher than those of the control, and there were no significant difference on the activities of the SOD and CAT between the 50μmol/L and the 200μmol/L, while the content of MDA of MT treatments were significantly lower than those of the control.