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[摘要]
目的 研究不同质量浓度铅(Pb)胁迫对冬凌草Rabdosia rubescens不同器官抗氧化酶活性和生长的影响,为Pb污染下的冬凌草生长调控提供依据。方法 Pb质量浓度(0、135、270、540 mg/L)、胁迫时间(50 d)分株水培试验,以超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、生长速率、生物量和Pb质量分数为指标,用分光光度计测定抗氧化酶活性、等离子发射光谱仪测定植株Pb质量分数。结果 不同质量浓度Pb胁迫下,冬凌草叶片和根系中的SOD活性均表现为先升后降,但叶片中的SOD活性各组之间无显著性差异;叶片中的POD活性在135、270 mg/L Pb胁迫下与对照之间无显著差异,但在540 mg/L下则显著提高,而根系的POD活性在各质量浓度Pb胁迫下均显著低于对照,具体表现为先下降后又逐渐回升;叶片CAT活性随Pb质量浓度的增加而显著提高,而根系的CAT活性均随Pb质量浓度的增加而递减。中、低质量浓度Pb胁迫对冬凌草的生长无显著影响,高质量浓度(540 mg/L)Pb处理与对照组相比,生物量和相对生长速率分别降低33.33%和46.59%。结论 Pb胁迫对冬凌草叶部和根部的抗氧化酶系统活性刺激反应有明显差异;经拟合模型预测分析,比对照相对生长速率降低10%的Pb临界质量浓度为301.99 mg/L(P<0.01)。冬凌草对Pb胁迫表现为较强的抗逆性。
[Key word]
[Abstract]
Objective To study the effect of different concentration of plumbum (Pb) stress on antioxidase activity in different organs of Rabdosia Rubescentis Folium (RRF, the aerial parts of Rabdosia rubescens) and their growth, and provide the basis for the growth regulation of R. rubescens under Pb pollution. Methods Ramets hydroponic test was performed with the concentration of Pb (0, 135, 270, and 540 mg/L) and the stress time (50 d), taking superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), relative growth rate (RGR), biomass, and Pb mass fraction as indexes, the determination of antioxidant enzyme activity was performed with spectrophotometer, and plant's Pb mass fraction of plant with plasma emission spectrometer was carried out. Results Under Pb stress at different concentration (135-540 mg/L), SOD activity in the leaves and the roots of R. rubescens was increased first and then decreased, but no significant difference on SOD activity in the leaves at each level; POD activity in the leaves under Pb concentration (135-270 mg/L) was no significant difference compared with the control group, but was significantly increased at the concentration of 540 mg/L, while the POD activity in the roots under Pb stress at various concentration was significantly lower than that of the control group which gradually went up after declined; CAT activity in the leaves increased significantly with Pb concentration rising, and the activity in the root decreased gradually with Pb concentration rising. No significant effect on the growth of R. rubescens at low and mid levels of Pb concentration (135 and 270 mg/L), but under high concentration (540 mg/L) of Pb treatment compared with the control group, the biomass and RGR decreased by 33.33% and 46.59%, respectively. Conclusion The stimulus response is different obviously for antioxidase activities between the leaves and roots of R. rubescens; Through fitting model predictive analysis, the critical Pb concentration is 301.99 mg/L, which decreases RGR by 10% compared with control group (P < 0.01). RRF shows a strong resistance to Pb stress.
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[基金项目]
国家自然科学基金资助项目(31370634)