钴在蚕豆中积累与分布的动态变化

On the dynamic change of cobalt accumulation and distribution in the broad bean

采用模拟钴污染土壤的方法，研究了不同质量比的钴污染土壤（0、10 mg/kg、25 mg/kg、40 mg/kg）对不同时期（初期、营养生长期、成熟期）蚕豆植株生长及各部位钴的积累与分布特征的影响。结果表明，1）在不同质量比的钴处理下，植株总生物量在成熟期均达到最大，钴质量比越高，对植株的毒害作用越大。当钴质量比为40 mg/kg时，成熟期植株的总生物量比对照组降低了70%。2）钴处理后，各时期植株不同部位钴质量比由大到小均为根部、叶部、其他部位。3）在初期和营养生长期，70%以上的钴积累在根部；而在成熟期，根部钴积累量所占比重急剧下降，此时籽实钴积累量比重达到22%~46%，表明在成熟期，大量的钴向籽实中转移积累。4）土壤钴质量比越高，植株单株钴积累量越大，并且中高质量比的钴明显抑制了植株持续积累钴的能力。当钴质量比为25 mg/kg、40 mg/kg时，单株积累量在营养生长期最大。5）随土壤钴质量比增加，植株将钴由根部转移至地上部的能力逐步降低，而地上部富集钴的能力越来越强，这在初期和营养生长期表现得比较明显。

In this paper, we have conducted a pot-planted investigative experiment to trace the dynamic change of cobalt accumulation and distribution in the broad bean was to the accumulation and distribution of cobalt in different parts of the bean plant at different growth stages （the early stage, the vegetative stage and the maturity stage） by imitating the different levels of cobalt polluted soils （0, 10 mg/kg, 25 mg/kg, 40 mg/kg）. The results have shown that： （1） The total biomass of the broad bean plant tends to reach the maximum value at the maturity stage when treated with different concentrations of cobalt in the soil;and, the higher the cobalt concentration is in the soil, the greater toxicity the cobalt concentration tends to affect the plant under growth. Therefore, as compared with the control group, the total biomass of the broad bean plant tends to decrease by 70% when the cobalt content accounts for 40 mg/kg. （2） The distribution of the cobalt content concentration in the different parts of the broad bean plant proves to be in a descending order, that is, the root〉the leaf〉the other parts. （3） Our experiments have also found that at the early sprout and vegetative stages, more than 70% of the cobalt content tends to be accumulated in the root, whereas at the maturity stage, the proportion of the cobalt content accumulated in the root turns to be declining sharply, with 22%-46% of the cobalt accumulation has been found in the seeds at the same time. This fact demonstrates that a great proportion of cobalt tends to transfer from the root to the seed at the ripping stage. （4） With the increase of the cobalt content in the soil, the cobalt accumulation in the said bean plant tends to get enhanced and its capability for continuing accumulation of cobalt in the plant would be significantly inhibited under high and medium cobalt content concentrations. For example, when the cobalt content concentration is 25 mg/kg and 40 mg/kg in the soil, the total cobalt accumulation in the plant tends to reach its maximum values at the vegetative stage. （5） With the increase of the cobalt content in the soil, the capability of the broad bean plant to transfer the cobalt from the root to the above-ground parts would be gradually reduced, but the enrichment capacity of the cobalt concentration in the above-ground parts turns to be much stronger, which tends to appear obviously at the early and vegetative stages.