| 不同作物对外源硒动态吸收、转运的差异及其机制 |
| 摘要点击 1972 全文点击 1157 投稿时间：2016-07-28 修订日期：2016-11-17 |
| 查看HTML全文
查看全文 查看/发表评论 下载PDF阅读器 |
| 中文关键词 硒酸盐 亚硒酸盐 动态吸收 转运 有效硒 |
| 英文关键词 selenate selenite dynamic uptake translocation available selenium |
|
| 中文摘要 |
| 查明作物硒吸收、转运随生育期的动态变化，有助于更好地了解硒在土壤-植物系统中的迁移进而对其有效性进行调控.本文采用盆栽试验，研究了6种不同作物在8周生长期内对外源硒酸盐和亚硒酸盐的动态吸收和转运差异及可能机制.结果表明，作物对硒酸盐和亚硒酸盐的动态吸收规律显著不同.硒酸盐处理作物地上部和根部硒含量从种植3周后持续下降；而亚硒酸盐处理作物根部硒含量随生长逐步上升，地上部硒含量随生长呈先上升后平稳或下降的趋势.两种硒处理在整个作物生长期内都有硒的累积，但植物体内80%的硒源于前6周的吸收.6种作物相比，硒酸盐处理芥菜地上部和根部硒含量最高，小麦地上部次之，亚硒酸盐处理，胡萝卜地上部硒含量最高，地下硒含量最小，而相同硒处理菜薹、紫甘蓝和绿菜花地上部和根部硒含量相近.绿菜花、紫甘蓝、菜薹、芥菜和小麦对硒酸盐的转运明显高于亚硒酸盐，胡萝卜对两种硒的转运能力相当.生物稀释作用影响作物硒含量的动态变化，尤以硒酸盐处理最为明显，供试植物硒含量与其干重呈显著负相关，但生物量改变引起的稀释作用并不能解释其对两种价态硒截然相反的吸收规律.进一步分析发现，硒酸盐处理6种作物硒累积量与作物生长期土壤有效硒改变量呈显著正相关（P<0.05），但亚硒酸盐处理却未发现此结果；6种作物硒累积量仅占亚硒酸盐处理土壤有效硒的0.5%~18.1%，而硒酸盐处理除胡萝卜外5种作物硒累积总量为土壤有效硒量的1.1~4.5倍，由此可见，作物对外源硒酸盐和亚硒酸盐动态吸收的差异是作物硒吸收和转运能力、土壤供硒能力及生物稀释综合作用的结果，在作物硒的强化中应该综合考虑. |
| 英文摘要 |
| 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. |
|
|
|
