Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, 11A Datun Road, Chaoyang District, Beijing 100101, China.
Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, 11A Datun Road, Chaoyang District, Beijing 100101, China; Department of International Health, Faculty of Health, Medicine and Life Sciences, Maastricht University, 6200 MD, Maastricht, The Netherlands.
Ecotoxicol Environ Saf. 2014 Apr;102:55-61. doi: 10.1016/j.ecoenv.2014.01.004. Epub 2014 Feb 1.
In this study, we performed a rhizobox experiment to examine the dynamic changes in the rhizosphere properties and antioxidant enzyme responses of Triticum aestivum L. under three levels of cadmium stress. A set of micro-techniques (i.e., Rhizobox and Rhizon SMS) were applied for the dynamically non-destructive collection of the rhizosphere soil solution to enable the observation at a high temporal resolution. The dynamics of soluble cadmium and dissolved organic carbon (DOC) in the rhizosphere soil solutions of the Triticum aestivum L. were characterised by the sequence week 0 after sowing (WAS0)<3 weeks after sowing (WAS3)<10 weeks after sowing (WAS10), whereas the soil solution pH was found to follow an opposite distribution pattern. Systematically, both superoxide dismutase (SOD) and catalase (CAT) activities in the leaves of the Triticum aestivum L. increased concomitantly with increasing cadmium levels (p>0.05) and growth duration (p<0.05), whilst ascorbate peroxidase (APX) activity was induced to an elevated level at moderate cadmium stress with a decrease at high cadmium stress (p>0.05). These results suggested the enhancement of DOC production and the greater antioxidant enzyme activities were two important protective mechanisms of Triticum aestivum L. under cadmium stress, whereas rhizosphere acidification might be an important mechanism for the mobilisation of soil cadmium. The results also revealed that plant-soil interactions strongly influence the soil solution chemistry in the rhizosphere of Triticum aestivum L., that, in turn, can stimulate chemical and biochemical responses in the plants. In most cases, these responses to cadmium stress were sensitive and might allow us to develop strategies for reducing the risks of the cadmium contamination to crop production.
在这项研究中，我们进行了根盒实验，以研究在三种镉胁迫水平下，小麦根际特性和抗氧化酶响应的动态变化。我们应用了一组微技术（即根盒和 Rhizon SMS），用于动态非破坏性地收集根际土壤溶液，以便能够以高时间分辨率进行观察。通过播种后第 0 周（WAS0）<播种后第 3 周（WAS3）<播种后第 10 周（WAS10）的顺序，我们可以发现小麦根际土壤溶液中可溶性镉和溶解有机碳（DOC）的动态变化，而土壤溶液 pH 值则呈现相反的分布模式。系统地说，随着镉水平（p>0.05）和生长时间（p<0.05）的增加，小麦叶片中的超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性同时增加，而过氧化氢酶（APX）活性在中等镉胁迫下诱导到较高水平，在高镉胁迫下则降低（p>0.05）。这些结果表明，DOC 产生的增强和更大的抗氧化酶活性是小麦在镉胁迫下的两个重要保护机制，而根际酸化可能是土壤镉活化的重要机制。研究结果还表明，植物-土壤相互作用强烈影响小麦根际土壤溶液的化学性质，这反过来又可以刺激植物的化学和生化反应。在大多数情况下，这些对镉胁迫的响应是敏感的，这可能使我们能够制定减少镉污染对作物生产风险的策略。
