稀土元素对短叶对齿藓生理生化的研究

通过测定分析3个主要生理指标过氧化物酶（POD）活性、丙二醛（MDA）含量和叶绿素含量的变化，研究了短叶对齿藓组培苗在6个不同浓度梯度的轻稀土La³⁺，Ce⁴⁺和重稀土Y³⁺单一元素胁迫下的生理响应和变化。结果如下：（1）短叶对齿藓体内的过氧化物酶（POD）活性和丙二醛（MDA）含量各处理组均低于对照组；Ce⁴⁺元素在3.55×10^-2 mmol·L^-1时显著提高了POD活性，在7.1×10^-2 mmol·L^-1时显著增加了膜脂过氧化产物丙二醛（MDA）含量。表明短叶对齿藓对Ce⁴⁺元素胁迫响应较强；而La³⁺元素各处理浓度间POD的变化较为平缓，胁迫响应较弱；Y³⁺处理居中。（2）较低浓度的La³⁺（1.8×10^-2 mmol·L^-1）和Ce⁴⁺（3.55×10^-2 mmol·L^-1）时显著提高叶绿素a、叶绿素b和总叶绿素含量；3种稀土元素在较高浓度时叶绿素的含量均有明显下降。本研究为进一步探明白云鄂博稀土矿区的苔藓植物生长发育受稀土元素的影响奠定了基础。

Influence of Rare Earth Elements on Physiological and Biochemical Characteristics of Didymodon tectorum

Based on the successful application of tissue cultured seedlings of Didymodon tectorum, three physiological indexes, including POD vitality, MDA and chlorophyll content were determined to check out the influences of the rare earth elements stress under gradient concentrations treatment. We choosed the light rare earth La³⁺, Ce⁴⁺ and heavy rare earth Y³⁺ three elements and setted respectively six concentrations under the single elemnet stress, in order to explore the physiological response and changes of D.tectorum to the rare earth stress. The results were the following:(1)The peroxidase(POD) activity and malondialdehyde(MDA) content in D.tectorum were lower in each treatment group than those in the control group; Ce⁴⁺ element significantly promoted the POD activity at 3.55×10^-2 mmol·L^-1, at 7.1×10^-2 mmol·L^-1, the content of MDA increased. It showed that the D.tectorum had a stronger response to Ce⁴⁺ stress, while La³⁺ showed a more gradual change in POD activity, and the stress response was weaker; Y³⁺ treatment was intermediate; (2)At lower concentrations of La³⁺(1.8×10^-2 mmol·L^-1) and Ce⁴⁺(3.55×10^-2 mmol·L^-1) the contents of chlorophyll a, chlorophyll b and total chlorophyll increased significantly, but at higher concentrations of all three rare earth elements, the contents of chlorophyll decreased obviousily. This study laid the foundation for further exploration of the effects of rare earth elements on the growth and the development of bryophytes in the Baiyun obo rare earth mineral area.