外源硅对盐胁迫下黄果厚壳桂幼苗的光合荧光及抗氧化特性的影响

Effects of Exogenous Silicon on Photosynthesis and Chlorophyll Fluorescence Characteristics and Antioxidant Enzymes of Cryptocarya concinna Seedlings Under Salt Stress

为探讨外源硅对盐胁迫下黄果厚壳硅的缓解作用。以一年生黄果厚壳桂(Cryptocarya concinna)幼苗为材料,在100 mg/L NaCl胁迫下,添加不同浓度(0、0.5、1、2 mmol/L)外源硅对幼苗进行处理,测定和分析不同处理下幼苗叶片的叶绿素含量、光合、叶绿素荧光特性参数和抗氧化酶含量。结果表明,外源硅能不同程度提高Pn、Tr、Gs、Fv/Fm,降低Ci;提高叶绿素a、叶绿素b和类胡萝卜素含量;提高SOD、PPO和APX活性,降低MDA含量。其中PPO在1.0 mmol/L硅处理下效果最佳,其他指标均在2.0 mmol/L硅处理效果最佳。可见,添加适度浓度硅可以缓解盐胁迫对黄果厚壳桂幼苗的伤害,提高其耐盐能力,该研究为黄果厚壳桂引种栽培提供参考。

In this study,one-year-old seedlings of Cryptocarya concinna were treated with different concentrations(0, 0.5, 1 and 2 mmol/L) of exogenous silicon under salt stress at 100 mg/L NaCl. The chlorophyll content, photosynthesis and chlorophyll fluorescence characteristics and antioxidant enzymes were determined and analyzed for investigating the effects of exogenous silicon on C. concinna exposed to NaCl stress. The results indicated that exogenous silicon could increase the contents of chlorophyll a, chlorophyll b and carotenoid, the activities of SOD, PPO and APX, and the values of Pn, Tr, Gs and Fv/Fm, while reduce the MDA content and Ci value. By comparing different treatments, PPO content was the highest under the treatment of adding 1.0 mmol/L Si and other indexes were the highest under the treatment of adding 2.0 mmol/L Si. In conclusion, the addition of appropriate concentration of exogenous silicon can alleviate the damage of salt stress to C. concinna seedlings and improve seedling salt tolerance. This study will provide reference for the introduction and cultivation of C. concinna.