铅胁迫对紫穗槐光合作用及生理生化特征的影响

以紫穗槐幼苗为材料,通过盆栽试验,研究不同浓度(0、100、300、600 mg·kg~(-1))铅(Pb)胁迫条件下,紫穗槐叶片中的丙二醛(MDA)含量、抗氧化酶(SOD、POD、CAT)活性等生理指标和光合作用参数以及叶绿素荧光参数对Pb胁迫的响应。结果表明:紫穗槐叶片中MDA含量和电解质外渗率随着Pb胁迫程度的增加呈升高趋势,Pb胁迫提高了紫穗槐叶片中抗氧化酶SOD、POD的活性;100 mg·kg~(-1)Pb胁迫处理下,紫穗槐净光合速率(Pn)显著高于对照组;Pb胁迫浓度达到300 mg·kg~(-1)时,紫穗槐抗氧化酶活性、相对叶绿素含量(SPAD值)显著升高;600 mg·kg~(-1)Pb胁迫下CAT活性开始有所降低,光合作用降低主要受非气孔限制因素的影响,对紫穗槐叶绿素荧光特性未造成严重损伤。说明紫穗槐对环境中Pb(600 mg·kg~(-1))污染的耐受能力较强。

Effects of Lead Stress on Photosynthesis and Physiological and Biochemical Characteristics of Amorpha fruticosa

The seedlings of Amorphafruticosa were cultured at lead concentration of 0 (control),100,300,600 mg· kg-1 respectively,under pot experiment to observe and analyze the response of physiological indicators such as malonaldehyde(MDA) content,activities of antioxidant enzymes(SOD,POD,CAT),photosynthesis and chlorophyll fluorescence parameters in leaves of A morphafruticosa to Pb stress.The results showed that with the increase of Pb concentration,the contents of MDA and activities of SOD and POD in leaves of A morphafruticosa increased.The net photosynthetic rate (Pn) was significantly higher than that of the control at 100 mg· kg-1 Pb stress treatment.When the Pb concentration reached 300 mg·kg-1,the activity of antioxidant enzymes and relative content of chlorophyll(SPAD) of A morphafruticosa increased significantly.The activities of catalases(CAT) began to decrease,the decrease of photosynthesis was mainly affected by nonstomatal limitation,and the chlorophyll fluorescence characteristics of A morphafruticosa were not seriously damaged when A morphafruticosa was under Pb stress of 600 mg· kg-1.It indicated that A morphafruticosa could resist Pb pollution(600 mg· kg-1) in the environment.