多粘类芽孢杆菌对油菜中锶富集和转移的影响

目的：研究根际促生菌——多粘类芽孢杆菌对油菜中锶富集和转移的影响。方法：实验分5组，设置4个不同锶浓度（1、2、3、4 mmol/L）处理组和1个对照组（水培养液）。利用水培方式培育油菜，水培养液中添加多粘类芽孢杆菌（0.333 g/L），于添加锶和菌后3个时间点（7、14、21 d）收获油菜，用电感耦合等离子体发射光谱仪（ICP-AES）分别测定油菜的根和茎叶中锶含量，并计算转移系数和富集率。结果：与对照组相比，多粘类芽孢杆菌存在时，油菜根部和茎叶中⁸⁸Sr含量随着培养液中锶浓度增高和作用时间的延长而升高（P < 0.05，油菜根部在1 mmol/L锶+菌作用21 d时除外），且油菜茎叶中的⁸⁸Sr含量大于油菜根部（P < 0.05）；多粘类芽孢杆菌使⁸⁸Sr的转移系数增加、富集率降低（P < 0.05），可促进⁸⁸Sr从根到茎叶的转移。4个处理组对⁸⁸Sr的转移系数均增加（P < 0.05），且转移系数均在21 d达到最高。结论：多粘类芽孢杆菌能够影响油菜对锶的转移和富集，可降低油菜根和茎叶部分对⁸⁸Sr的富集率，促进⁸⁸Sr从根到茎叶的转移。

Effect of Paenibacillus polymyxa on strontium enrichment in rape

OBJECTIVE:This paper was to study on the effects of rhizosphere growth promoting bacteria Paenibacillus polymyxa on strontium enrichment in rape.From the aspect of food safety assessment,it was of practical significance to explore the characteristics of enrichment and transfer of typical radionuclide strontium in vegetables.It also provided a theoretical basis for the feasibility of phytoremediation of contaminated soil.METHODS:The experiment was divided into 5 groups:4 different strontium concentration treatment groups and 1 control groups (hydroponics blank control).The vegetable was cultivated by hydroponic method and Paenibacillus polymyxa was added.Vegetables were harvested at 3 time points (7 d,14 d,21 d) after adding Paenibacillus polymyxa to the hydroponic solution.Then the concentration of strontium in roots,stems and leaves of rape was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) and the concentration ratios and transportation factors were calculated.RESULTS:Compared with blank control groups,when Paenibacillus polymyxa was present,strontium concentrations in the stems,leaves and roots of rape increased with strontium concentration in hydroponic solution and increased with the number of cultivation days (P＜0.05) (except rape roots of 1 mmol/L strontium concentration in hydroponic solution with 21 d).The content of strontium in stems and leaves of rape was greater than that in rape roots (P＜0.05).Paenibacillus polymyxa led to reduction of the concentration ratios of strontium but to increase of the transportation factors which promoted the transfer of strontium from root to stem and leaf.TF(transportation factor) of strontium increased in experiment groups 1,2,3 and 4,with increased number of days to reach the highest in 21 days.CONCLUSION:Paenibacillus polymyxa significantly affected the transfer of strontium in rape.It reduced the concentration ratios of strontium in roots,stems and leaves of rape,and promoted the strontium transfer from root to stem and leaf.