铁营养状况对黄瓜幼苗吸收转运镉和锌的影响

用营养液培养的方法,研究不同铁营养状况对黄瓜幼苗吸收和转运镉、锌的影响。结果表明:不供铁处理的黄瓜不同部位(根、茎、叶)镉含量与供铁处理差异显著,以茎中最为明显,茎中镉含量分别是供铁50、100、200μmol·L-1处理的2.9、2.8、2.4倍,不供铁处理显著增加了黄瓜各部位镉的含量;不供铁处理也显著提高了黄瓜根和叶片中锌的含量,但对茎中锌的含量没有产生显著影响。黄瓜根系吸收镉和锌的总量与吸收铁的总量表现出显著的负相关关系。随着铁供应浓度的升高,镉在根中的分配增加,与缺铁相比,供铁200μmol·L-1处理根中分配系数上升43%,而茎、叶中分别下降59%和44%,其对锌的分配则无显著影响。与供铁相比,不供铁明显促进黄瓜根、茎、叶对镉的吸收,提高镉在黄瓜地上部的分配及由根向茎转运镉的能力。

Effects of Iron Supply on Cadmium and Zinc Uptake and Translocation by Cucumber Seedlings

We would like to dedicate this paper to 2015 the International Year of Soil. Monitoring and control methods for the quality and the safety of soil environment and agricultural products based on loading capacity of soil for heavy metals were essentially a set of measures of cleaner production during entire process of farmland management. The method can reduce or avoid the negative effects of heavy metals on soil and crops. This article focuses on the necessity and possibility of the monitoring and control methods based loading capacity of soil for pollution management and control, emphasizing the importance of the legal backing, namely the legitimacy of the method. The differences between the loading capacity-based methods and the traditional management approaches based on environmental standards are (1)The environmental standard-based management only controls a single numerical endpoint; the loading capacity control method is three-dimensional, controlling the full range of processes. (2)The environmental standard-based management is concentration control; the loading capacity-based method is total amount control of pollutants. (3)The subject of liability in the environmental standard-based management is not clarified, led to great passive dependence on the authorities; the loading capacity-based method takes the initiative for differentiating the main responsibility will not affect the prevention and control of heavy metal pollutions whether the uniform criteria established or not. (4)The environmental standard-based management may cause inadequate control or over-protection in certain circumstances; the loading capacity-based method adopts the essence of "Land Suitability Science" and fully utilizes the soil productivity. (5)The criteria assignment of heavy metals in the environmental standard-based management is too "unified", without considering the specialities of regional environments; the loading capacity-based method supplies the critical levels for each particular region, aiming at the protection of the safety of agricultural products. The characteristics and advantages of the control methods based the loading capacity of soil are discussed in detail. It can be used as a beneficial supplement to the standards and as a substitute under the premise of the legal recognition for effective prevention and control of soil pollution.