镉胁迫对黄瓜幼苗的影响及调理剂对土壤中镉赋存形态的响应

发布时间：2018-03-09 10:02

  本文选题：镉　切入点：黄瓜　出处：《山东农业大学》2017年硕士论文　论文类型：学位论文

【摘要】：目前,由于工业废水、酸沉降和不合理的农田施肥措施导致土壤的酸化进程加快,致使土壤中重金属离子溶解度提高,有效态含量增加,移动性增强,不仅对作物产生毒害,也对人体健康构成威胁。本试验通过添加调理剂降低土壤pH,研究酸化后土壤中镉形态的变化,探究土壤酸化对镉形态及有效性的影响。通过研究酸化土壤条件下镉的赋存形态的变化和转化规律,对于揭示土壤酸化对重金属溶解度和释放潜力的影响具有一定的意义。研究结果如下:(1)镉胁迫下黄瓜株高受到抑制,在(0~300μmol·L~（-1）)镉浓度范围内,华南型均高于等镉浓度时的其它4种类型。中低镉浓度(0~50μmol·L~（-1）)可以刺激黄瓜幼苗根体积的增加,镉浓度为100~300μmol·L~（-1）时明显抑制根的生长。各类型黄瓜幼苗的抗氧化酶(SOD、POD、CAT)活性整体呈现先增后降的趋势,欧美温室型POD和CAT活性低于其它类型。50μmol·L~（-1）镉浓度以下时,幼苗地上部镉含量整体高于根部,100~300μmol/L浓度时则相反;300μmol·L~（-1）时,欧美加工型和华北Ⅰ型地上部镉含量显著低于其它处理,表现出较好的低累积特征。(2)随着培养时间的延长,随调理剂用量的增加显著的降低了土壤pH值,至56d时,最大降低了1.83个单位。土壤pH值的降低对土壤中镉的赋存形态有显著影响,减少了土壤中碳酸盐态镉的含量,使其转化成可交换态镉。随pH值的降低,铁锰结合态镉的含量增加。但pH值对土壤中有机结合态和残渣态的镉含量无显著影响。(3)15g·kg~（-1）调理剂用量显著增加了印度芥菜的生物量,促进了其叶和根的生长。但高用量的调理剂抑制了其生长。30g·kg~（-1）用量的调理剂对印度芥菜的生理代谢有显著的抑制作用。其中叶绿素含量、净光合速率等光合指标及抗氧化酶活性均显著低于对照。15g·kg~（-1）的调理剂用量对其无显著影响。随调理剂用量的增加,抑制了土壤脲酶、蔗糖酶、过氧化氢酶的活性,促进了土壤酸性磷酸酶的活性,各处理之间差异显著。15g·kg~（-1）调理剂用量降低了芥菜单位质量中镉的含量,但因其生物量的增加,增加了镉的积累量,与对照相比增加了169.86%。(4)试验表明调理剂的施用,使土壤的pH降低,使潜在利用态和不可利用态的镉转化为可利用态的镉,增加了超积累植物印度芥菜镉的吸收量,减少了土壤中镉的含量。但土壤的pH降低,使土壤中重金属镉离子浓度增大,有效态含量增加,移动性增强。因此,土壤酸化对土壤重金属镉的形态转化和溶出的影响应该引起关注,通过有效的措施防止土壤酸化,降低土壤和蔬菜中的重金属污染显得尤为重要。
[Abstract]:At present, due to industrial wastewater, acid deposition and unreasonable fertilization measures in farmland, the acidification process of soil is accelerated, and the solubility of heavy metal ions in soil is increased, the effective state content is increased, and the mobility is enhanced, which is not only toxic to crops, but also harmful to crops. In this study, the pH of soil was reduced by adding conditioning agent to study the changes of cadmium forms in acidified soil. The effects of soil acidification on the forms and availability of cadmium were studied. The results were as follows: the plant height of cucumber was inhibited under cadmium stress, in the range of 300 渭 mol 路L ~ (-1) ~ (-1) CD ~ (2 +), the effect of soil acidification on the solubility and release potential of heavy metals was studied. The South China type was higher than the other four types when the concentration of cadmium was equal. The root volume of cucumber seedlings could be increased by 50 渭 mol 路L ~ (-1) of low and low cadmium concentration. The activity of antioxidant enzyme SODPOD (CAT-1) of cucumber seedlings increased first and then decreased. The activities of POD and CAT in Europe and America were lower than those in other types of cucumber seedlings under cadmium concentration of .50 渭 mol 路L ~ (-1), and the activities of POD and CAT in greenhouse type were lower than those in other types of cucumber seedlings under the cadmium concentration of .50 渭 mol 路L ~ (-1), while the activities of POD and CAT in Europe and America were lower than those in other types of cucumber seedlings. When the CD content in shoot was higher than that in root (100 渭 mol 路L ~ (-1)), the CD content of American and European type and type 鈪，

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