康定柳对铯胁迫的生理生化响应及富集能力

Accumulation and physio-biochemical responses of Salix paraplesia to caesium stress

主要探讨康定柳(Salix paraplesia)在水培条件下对铯胁迫(133Cs+浓度0、50和200μmol/L)的生理生化响应和富集修复能力。研究结果表明:铯胁迫造成了植物的过氧化损伤,且与胁迫浓度呈正相关;植物通过提高渗透调节能力(Pro)和抗氧化能力(SOD、POD和CAT)应对铯胁迫,但高浓度铯胁迫却显著抑制了植株抗氧化系统的作用。从植物光合荧光指标和叶绿素含量来看,低浓度铯能促进植物叶绿素合成且对光合能力影响不大,而高浓度铯胁迫则抑制了植物叶绿素的合成及光合能力。此外,与对照相比,低浓度铯胁迫能够显著促进植株的茎长,而高浓度铯胁迫则显著抑制了植株的生物量、根长和茎长,对植株生长发育的抑制作用明显。康定柳对水体中铯的富集量和富集系数均表现为根>茎>叶,铯主要富集在植株根部,且在高处理浓度下,植株富集量最高达到2.235 8 mg/g DW。表明康定柳对水体中铯的污染具有较好的耐受性和修复潜力。

The physio-biochemical responses and accumulations of Salix paraplesia to cesium（^133Cs^＋0,50 and 200 μmol / L） stress under hydroponic condition were studied. Our results showed that the Cs stress caused peroxidation damage to S. paraplesia,which was positively correlated with the stress concentration. Adapting to the Cs stress,S. paraplesia would improve the osmotic adjustment（ Pro） and antioxidant ability（ SOD,POD and CAT）; however,the antioxidant systems were obviously inhibited by high Cs concentration stress. Regarding the photosynthetic fluorescence indexes and chlorophyll contents,our results indicated that a low concentration of Cs stress could improve the biosynthesis of chlorophyll rather than negatively affecting photosynthesis. However,both biosynthesis of chlorophyll and photosynthesis were obviously inhibited by the high level of Cs stress. In addition,compared with the control treatment and low concentration of Cs stress that only improved the growth of the stem length,the high concentration of Cs stress could significantly inhibit plant biomass,root length,and stem length,indicating adverse effects on the growth and development of S. paraplesia. Moreover,the enrichment and enrichment coefficient of Cs by S. paraplesia were as follows： root 〉stem〉 leaf. The root proved to be the main accumulation area of the plant,in which the highest enrichment reached 2. 235 8 mg / g DW. In conclusion,our results indicated that S. paraplesia is tolerant to Cs stress and proved to be a potential plant to be used in Cs remediation.