铅胁迫对滇润楠幼苗生理特性的影响

Effect of Plumbum Stress on Physiological Characteristics of Machilus yunnanensis Seedlings

以2a生滇润楠实生幼苗为试材,研究了对照(CK)、5mmol/L Pb(NO3)2、10mmol/L Pb(NO3)2铅胁迫处理对其部分生理生化特性的影响。结果表明:Pb2+胁迫处理下,叶片初始荧光(F0)呈现上升趋势,PSII最大光化学效率(Fv/Fm)和PSII实际光合效率(Yield)显著受Pb2+的影响,且在低浓度的Pb2+浓度胁迫下呈现出显著下降趋势,表明在Pb(NO3)2溶液处理下的滇润楠幼苗光系统II受到损伤,且5mmol/L浓度处理比10mmol/L浓度处理对其伤害更大。此外,Pb2+胁迫引起植株叶绿素含量先降后升、可溶性蛋白含量显著下降,导致膜脂过氧化产物丙二醛(MDA)含量的增加,且在5mmol/L的处理浓度下的变化较大。同时Pb2+胁迫使过氧化物酶(POD)活性显著提高,在低浓度铅胁迫下脯胺酸含量显著降低,表明该幼苗可以通过启动抗氧化酶系统及渗透调节来抵御铅胁迫。

Taking two-year old seedlings of Machilus yunnanensis as experiment material,the effect of some physiological and biochemical characteristics under three stress treatment groups control （CK）, 5 mmol/L Pb（NOa ）2,10 mmol/L Pb（NOa ）2 were studied. The results showed that under the Pb2＋ treatment,the initial fluorescence （F0） increased,while the maximal photochemical efficiency of PSII （Fv/Fm） and the actual photochemical efficiency of PSII （Yield） decreased significantly in the low Pb2＋ concentration,which indicating the PSII of Machilus yunnanensis seedlings was damaged by Pb（NO3 ）2treatment, especially by the 5 mmol/L concentration of Pb （NOa）2 treatment. Furthermore, the contents of chlorophyll dropped and then increased as Pb2＋ concentration raised continually. Soluble protein contents declined obviously, and significantly stimulated the increase of MDA content;moreover, these changes were more evident under the 10 mmol/L concentration treatment. On the other hand, the Pb2＋ stress promoted the POD activity and decreased the accumulation of praline significantly in low concentration of Pb2. , which suggested the Machilus yunnanensis seedlings could resist Pb2＋ stress by its antioxidative enzyme and osmotic regulation system.