Peng Qin, Li Zhe, Liang Dong-Li, Wang Meng-Ke, Guo Lu
College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China.
Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling 712100, China.
Huan Jing Ke Xue. 2017 Apr 8;38(4):1667-1674. doi: 10.13227/j.hjkx.201607205.
The study aimed to find out the dynamic changes of selenium (Se) uptake with crops growing and to provide better understanding on the translocation of Se in soil-plant system. Pot experiments and laboratory analysis were carried out, in which 6 crops were planted for eight weeks in the soils treated with selenite and selenate. The results showed that there was a significant difference in the plant dynamic uptake pattern for selenite and selenate. Se concentration in shoots and roots of all tested plants continuously declined with growth since the third week after planting for selenate treatment; while Se concentration in roots of plants gradually increased with the growth, and that for shoots firstly increased and then leveled off or decreased for selenite treatment. Crops could accumulate Se throughout the whole growing period, while 80% of the Se in plants was uptaken in the first 6 weeks. Among the 6 tested plants, the Se concentration in the shoots and roots of mustard was the highest, followed by the shoots of wheat for selenate treatment. The Se concentration in shoots of carrot was the highest, while that in roots was the lowest for selenite treatment. For the same Se treatment, the Se concentrations in both roots and shoots of broccoli, purple cabbage and flowering Chinese cabbage were similar. Broccoli, purple cabbage, flowering Chinese cabbage, mustard and wheat had higher translocation ability to transport selenate than selenite from roots to shoots, whereas carrot had the same ability for translocating selenite and selenate. Biological dilution affected the dynamic changes of the Se content in crops, especially for selenate treatment, and a significant negative correlation between Se concentration of plants and their biomass further verified this. However, the changes of biomass of plants with growing period couldn't explain the total inverse dynamic uptake pattern for selenite and selenate. A significant positive correlation was observed between Se accumulations amount in six crops with available Se changes in soil during the corresponding growing period for selenate treatment, while no such correlation was found for selenite treatment. Se accumulation in crops grown on selenite-treated soil accounted for 0.5%-18.1% of soil available Se, whereas that in selenate treatment was 1.1-4.5 times of soil available Se except for carrot. In conclusion, the dynamic changes of Se uptake with crop growth were the comprehensive results of the absorption and transport capacity of crops, Se availability in soil and biological dilution. It should be considered as a whole in the selenium biofortification.
本研究旨在探究作物生长过程中硒（Se）吸收的动态变化，以便更好地理解土壤 - 植物系统中硒的转运情况。进行了盆栽试验和实验室分析，在亚硒酸盐和硒酸盐处理的土壤中种植6种作物，为期8周。结果表明，亚硒酸盐和硒酸盐的植物动态吸收模式存在显著差异。对于硒酸盐处理，自种植后第三周起，所有受试植物地上部和根部的硒浓度随生长持续下降；而对于亚硒酸盐处理，植物根部的硒浓度随生长逐渐增加，地上部的硒浓度则先增加，然后趋于平稳或下降。作物在整个生长期间都能积累硒，而植物中80%的硒在前6周被吸收。在6种受试植物中，芥菜地上部和根部的硒浓度最高，对于硒酸盐处理，其次是小麦地上部。对于亚硒酸盐处理，胡萝卜地上部的硒浓度最高，而根部的硒浓度最低。对于相同的硒处理，西兰花、紫甘蓝和小白菜地上部和根部的硒浓度相似。西兰花、紫甘蓝、小白菜、芥菜和小麦从根部向地上部转运硒酸盐的能力高于亚硒酸盐，而胡萝卜转运亚硒酸盐和硒酸盐的能力相同。生物稀释影响了作物中硒含量的动态变化，尤其是对于硒酸盐处理，植物硒浓度与其生物量之间的显著负相关进一步证实了这一点。然而，植物生物量随生长时期的变化并不能解释亚硒酸盐和硒酸盐完全相反的动态吸收模式。对于硒酸盐处理，观察到6种作物中的硒积累量与相应生长期间土壤有效硒变化之间存在显著正相关，而对于亚硒酸盐处理则未发现这种相关性。在亚硒酸盐处理土壤上生长的作物中，硒积累量占土壤有效硒的0.5% - 18.1%，而对于硒酸盐处理，除胡萝卜外，是土壤有效硒的1.1 - 4.5倍。总之，作物生长过程中硒吸收的动态变化是作物吸收和运输能力、土壤中硒的有效性以及生物稀释的综合结果。在硒生物强化中应将其作为一个整体来考虑。
