印度芥菜生理生化特性及其根区土壤中微生物对Cd胁迫的响应

通过盆栽试验研究了印度芥菜对土壤Cd污染的耐性及其生理生化特性响应。结果表明,印度芥菜对Cd胁迫表现了较强的耐性,在Cd添加量为0～200mg·kg-1的情况下,印度芥菜能够顺利发芽、生长,其生物量出现了先增后降的＂抛物线型＂变化规律,Cd主要影响其生殖生长,大量的Cd使印度芥菜延迟进入生育期。植株体内Cd浓度随土壤Cd浓度增加而升高,地上部可达7.824～102.672mg·kg-1,地下部可达0.374～191.910mg·kg-1。地上部富集系数呈逐渐降低的趋势,而地下部富集系数呈逐渐升高的趋势。转移系数为20.920～0.535,呈逐渐降低趋势。随着土壤Cd胁迫浓度的增加,印度芥菜3种酶活性均呈先增后降的＂抛物线型＂变化趋势,并且出现抗性酶活性高峰所对应的土壤Cd浓度相同,均为120mg·kg-1,在Cd高浓度水平下酶活性普遍受到抑制,在最高浓度处理时的酶活性均明显低于对照。根区土壤中微生物数量为细菌〉放线菌〉霉菌,随着Cd添加量的增加,土体内微生物的数量也增加,但当Cd添加量〉160mg·kg-1时,微生物数量下降。

Effects of Cd Contamination on Number of Microbes,Physiological and Biochemical Characteristics of Brassica juncea

Series of pot experiments were performed to determine the effects of cadmium in soil on chlorophyll content,CAT,POD and SOD activities in Brassica juncea.The results indicated that tolerance of Brassica juncea for Cd was stronger.It was able to burgeon and grow all right in the soil added Cd from 0 to 200 mg·kg-1.The biomass of Brassica juncea taken on principle of parabola changes with Cd concentration in the soil.Nevertheless,Cd influenced the growth stages of Brassica juncea to postpone its procreating growth.Cd concentration of Brassica juncea gone to increase with the content of Cd in the soil.The contents of Cd was 7.824~102.672 mg·kg-1 in the aboveground parts and 0.374~191.910 mg·kg-1 in the underground parts.The bioaccumulation factor of the ground part was falling and underground part was rising during the Cd is rising.Meanwhile,the translocation factor was 20.920~0.535.It taken on gradually falling trend.The POD,CAT and SOD activities increased at lower Cd concentrations,but decreased at higher Cd concentrations.Added Cd in the soil was 120 mg·kg-1,the POD,CAT and SOD activities was highest.The number of microorganisms was Bacteriaactinomycetesmould.The number of microbes was increasing during the Cd added in the soil.When the added Cd was more than 160 mg·kg-1,the number of microbes was going down.