冀北山地土壤养分和肥力对海拔梯度的响应

【目的】为研究冀北山地土壤养分和肥力对海拔梯度的响应,揭示土壤养分含量、化学计量特征和肥力的海拔梯度差异,为区域生态公益林可持续经营提供理论依据。【方法】以河北小五台山不同海拔梯度典型植被类型0~60 cm土壤为研究对象,分析了土壤有机质(SOM)、全氮(TN)、全磷(TP)、全钾(TK)、碱解氮(AN)、速效磷(AP)、速效钾(AK)及C、N、P、K化学计量特征的海拔梯度差异,通过主成分分析和相关分析方法选取土壤肥力评价指标,对不同海拔梯度土壤肥力进行了综合评价。【结果】1)随海拔梯度升高,土壤有机质、全氮、碱解氮、全磷、全钾和C/N、C/P、C/K、N/K升高,而速效磷、速效钾和N/P、P/K无明显变化规律。2)小五台山不同海拔梯度0~60 cm土层土壤有机质含量变化范围为19.77~70.69 g·kg^-1;全氮、全磷、全钾含量分别为0.85~2.34、0.26~0.86、7.60~10.31 g·kg^-1;碱解氮、速效磷、速效钾含量分别为72.26~206.61、0.30~0.50、64.03~130.90 mg·kg^-1。3)土壤C/N、C/P、C/K随海拔升高的变化范围分别为12.79~18.72、22.51~75.75、1.50~4.31;N/K、N/P、P/K变化范围分别为0.11~0.27、1.76~4.67、0.03~0.10;土壤C/N变异系数最小,C/K变异系数最大。4)经土壤肥力指数(SFI)综合评价,小五台山SFI与海拔高度显著正相关(R^2=0.68,P<0.01)。【结论】参照全国第二次土壤普查标准,小五台山土壤有机质、全氮、碱解氮含量较高,全磷和速效钾含量处于中间水平,而全钾和速效磷含量比较低,在森林经营中应注意补充。SFI指数显示小五台山海拔越高土壤肥力越好。

山涧口流域2种林分降雨及再分配特征

为分析山涧口流域白桦林和落叶松人工林降雨的再分配特征,针对林分的降雨、穿透雨、树干径流、枯落物渗透水、坡面径流5个方面,从pH值、HCO_3^-、Ca^(2+)、Mg^(2+)、Zn^(2+)、Mn^(2+)、Fe^(2+)7种化学指标进行测定与分析。结果表明:(1)与降雨相比,落叶松林在降雨再分配过程中pH值与Mg^(2+)含量下降; Ca^(2+)、Mn^(2+)含量升高; Zn^(2+)含量在穿透雨及坡面径流中下降,其它过程升高; Fe^(2+)含量在穿透雨及树干径流中下降,其它过程升高; HCO_3^-含量在穿透雨中升高,其它过程下降。(2)比较白桦与落叶松2种林分的水化学特征可知,在各个分配过程中2种林分对于测定物质有不同的影响,并且数量改变也存在明显的差异,其中差异最大的是HCO_3^-。(3)落叶松土壤流失的营养物质种类及数量多于白桦林,水源涵养功能低于白桦林,从发挥生态功能角度出发白桦林优于落叶松林。

Genetic imprinted gene PEG10 expression in deciduas of normal early pregnant women

Objective: To investigate the role and significance of paternally expressed gene 10 (PEG10) in deciduas of normal pregnant women. Methods: Sixty deciduas tissue from pregnant 6 to 11 weeks were divided into six groups and in each group ten samples were done every gestational week. The expression and distribution of PEG10 in deciduas were examined by RT-PCR, hybridization in situ, Western Blot and laser scanning confocal microscopy. Results: The PEG10 mRNA and protein were expressed in deciduas tissue from pregnant 6 to 11 weeks. Among them, the expression of PEG10 showed a gradual increase as the pregnancy weeks increased. In RT-PCR, the PEG10 expression was lower at pregnant 6th week (0.6743±0.114), from pregnant 7 to 8 weeks, the expression was increased gradually (7th week 0.7349±0.0083) and reached the pinnacle at 8th week (0.7354±0.0074). And then the pinnacle began to descend (9th week 0.6340±0.0084, 10th week 0.5901±0.0089 and 11th week 0.5261±0.0112). There was a significant difference in the expression of PEG10 from pregnant 6 to 11 weeks except 7th week and 8th week. This expression characteristic was demonstrated by hybridization in situ. The similar conclusion was proved by Western Blot and laser scanning confocal microscopy. Conclusion: Expression of PEG10 may play an important role in early pregnancy.