摘要
[目的]研究镉(Cd)对紫花苜蓿(Medicago sativa)生长和结瘤固氮的影响。[方法]采用盆栽试验。[结果]在土壤中Cd添加量较低的处理中,Cd对紫花苜蓿地上部分生物量、株高和叶绿素含量影响不大;当土壤中Cd添加量达到10.0mg/kg时,Cd对地上部分生物量影响显著;当土壤中Cd添加量达到50.0mg/kg时,植株生长和叶绿素合成均受到明显抑制。紫花苜蓿体内Cd含量的分布次序为根部>地上部分,且不同部位Cd的含量与处理中Cd添加量呈极显著相关(P<0.01)。随着土壤中Cd添加量的增大,单位盆钵中紫花苜蓿根瘤鲜重不断下降。当土壤中Cd添加量达到5.0mg/kg时,紫花苜蓿的根瘤固氮酶活性受到严重抑制。[结论]紫花苜蓿及其共生固氮体系对Cd具有一定的耐性,但较高浓度的Cd不仅会导致紫花苜蓿地上部Cd含量超标,也会抑制其生长和固氮。
[Objective] The research aimed to study the effects of cadmium on growth,nodulation and nitrogen fixation of Medicago sativa.[Method] The pot experiment was used.[Result] The results showed that there was little effects of cadmium on aboveground biomass,height and chlorophyll content of Medicago sativa in treatments with low cadmium addition.Effects of cadmium on aboveground biomass was significant in treatment with cadmiumaddition of 10.0 mg/kg soil,and growth and chlorophyll synthesis of Medicago sativa were significantly restrained in treatment with cadmiumaddition of 50.0 mg/kg soil.The distribution of cadmium content in Medicago sativa could be sequenced as：Rootaboveground part.Cadmium content in different parts of Medicago sativa had significantly positive relation to cadmium addition in the soil（P0.01）.Average fresh weight of root nodule in different pots declined along with increase of cadmium addition in treatments.Nitrogenase activity in the treatment began to be significantly restrained when cadmium of 5.0 mg/kg soil was added into the soil.[Conclusion] The study implied that Medicago sativa and N-fixing symbiosis had certain tolerance to cadmium pollution,and cadmiumof higher content in soil would induce cadmiumcontent in aboveground part of Medicago sativa exceed standard,and restrained the growth and nitrogen fixation of Medicago sativa.
出处
《安徽农业科学》
CAS
北大核心
2010年第12期6421-6423,6476,共4页
Journal of Anhui Agricultural Sciences
基金
中国博士后科学基金项目(20090460716)
重庆市自然科学基金项目(CSTC
2009BB1108)
国家科技支撑计划项目(2007BAD87B10
2008BABA7B09)
中央高校基本科研业务费专项基金项目(XDJK2009C060)
关键词
Cd
苜蓿
叶绿素
固氮酶
Cadmium
Alfalfa（Medicago sativa）
Chlorophyll
Nitrogenase
