镉胁迫对滇润楠幼苗生理特性的影响

Effect of Cadmium Stress on Physiological Traits in Machilus yunnanensis Seedlings

以两年生滇润楠实生幼苗为材料,用CdCl2溶液对其进行胁迫处理,共设3个组(对照CK组),10 mmol/L CdCl2处理组,20 mmol/L CdCl2处理组,研究其部分生理生化特性对重金属Cd2+胁迫的响应。主要研究结果为:Cd2+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Cd2+的影响,随着Cd2+浓度的增加呈现出显著下降趋势,说明在CdCl2溶液处理下的滇润楠幼苗光系统II受到损伤,且高浓度处理比低浓度处理对其伤害更大。此外,Cd2+胁迫引起植株叶绿素含量、可溶性蛋白含量的下降,刺激了膜脂过氧化产物丙二醛(MDA)含量的显著增加,且在20 mmol/L的处理浓度下的变化更大。同时Cd2+胁迫也显著提高了过氧化物酶(POD)活性及促进了脯胺酸含量的累积,说明该幼苗可以通过启动抗氧化酶系统及渗透调节来抵御镉胁迫。

In this study, two - years old seedlings of Machilus yunnanensis were used as the experiment materials, some physiological and biochemical characteristics were determined under three treatment groups （the control group CK, the CdC12 treatment group with 10 mmol/L concentration and the CdC12 treatment group with 20 mmol/L concentration）. The results are as follows：under the Cd2 ＋ treatment, the initial fluorescence （F0） increased, while the maximal photochemical efficiency of I？SII （Fv/Fm） and the actual photochemical efficiency of PSI! （Yield） decreased significantly with the increage of Cd2＋ concentration,which indicating that the PSII of Machilus yunnanensis seedlings was damaged by the CdCl2 treatment, especially by the higher con- centration of CdC12 treatment. Furthermore, the Cd2＋ treatment caused the decline of chlorophyll and soluble protein contents, and significantly stimulated the increase of MDA content; moreover, these changes were more evident under the 20 mmol/L concentration treatment. On the other hand, the Cd2 ＋ stress promoted the POD activity and accelerated the accumulation of proline, which suggested that the Machilus yunnanensis could resist Cd2＋ stress by its antioxidative enzyme and osmotic regulation system.