In order to study the impact of sewage irrigation and cadmium stresses on the growth process and cadmium accumulation in spinach ( Spinacia oleracea L. ) ,the spinach planted in pots were irrigated and sprayed with tap water and sewage water,both containing Cd2+ of various concentrations. The results show that Cd2+-contai-ning sewage imposed higher inhibiting effects than the Cd2+-containing tap water,as evidenced by lower values of plant height,leaf area and average number of leaves per pot,as well as the significantly higher cadmium concentra-tions in the tissue. The comparisons with the control group show that the tissue cadmium increased along with the in-creasing of Cd2+ exposure concentration in both treatments of Cd2+-containing tap water and Cd2+-containing sew-age water. Two distinguishable stages of the increase in tissue cadmium were identified. At the first stage,significant linear relationships with correlation coefficients of 0. 999 6 and 0. 997 6 were observed with the slopes of 1. 602 9 and 1. 665 6 for the spinach exposed to 0-10 mg/L of Cd2+-containing tap water and Cd2+-containing sewage water re-spectively. At the second stage,significant linear relationships with correlation coefficients of 0. 997 9 and 0. 999 8 were observed with the slopes of 0. 237 3 and 0. 254 8 for the plants exposed to 10-50 mg/L of Cd2+-containing tap water and Cd2+-containing sewage water respectively. The slope of the second stage is notably smaller than the first stage. The threshold concentration of cadmium pollution to spinach growth was found 10 mg/L. The Cd2+-containing sewage water may stimulate spinach growth at low concentration,but impose inhibition at higher concentrations,in the measurement of spinach height,leaf area,number of leaves,stem diameter and biomass.%为了研究污水灌溉和镉胁迫复合处理对菠菜镉积累和生长过程的影响,采用盆栽试验,用清水和污水分别配制不同浓度(0,1,5,10,30,50 mg/L)的镉溶液,定期对菠菜整个生长过程进行浇灌和喷洒处理。结果表明,与清水处理系列相比,污水灌溉有利于菠菜对土壤镉的吸收,且相同浓度的污水处理系列的菠菜株高、叶面积、每盆平均叶片数、生物量等均低于清水处理系列。与各自的空白对照相比,2个处理系列的菠菜镉含量均随着处理试液镉离子浓度的增大而增大,呈现双阶段直线相关性；当镉浓度在0~10 mg/L时,清水和污水系列菠菜镉含量与处理试液镉浓度的线性相关系数分别为0.9996,0.9976,相关直线斜率分别为1.6029,1.6656；当处理试液镉浓度为10~50 mg/L时,二者的直线相关系数分别为0.9979,0.9998,斜率分别为0.2373,0.2548,斜率变小。2个处理系列的菠菜株高、叶面积、每盆平均叶片数、生物量等均在0~10 mg/L表现出低浓度刺激效应,10~50 mg/L表现出高浓度抑制效应。
展开▼
