实验以甘草(Clycyrrhiza uralensis Fiach)植被和其下部土壤为研究对象,通过测定甘草植被的盖度、高度、地上生物量和土壤表层(0~5 cm)的水、盐、有机质含量等指标,来揭示甘草植被对土壤理化性质的影响.结果表明,随着生长年限的增加,甘草植被的盖度、高度、地上生物量和其下部土壤表层的含水率、有机质含量呈显著升高趋势(P<0.05),而土壤盐含量却呈显著下降趋势(P<0.05);土壤的水、有机质含量与甘草植被的盖度、高度、地上生物量间表现出极显著的正相关关系(P<0.01),而土壤的盐含量与它们间却表现出极显著的负相关关系(P<0.01);进一步通径分析显示,甘草植被的地上生物量对土壤的水、盐、有机质含量均有较大的直接作用,而盖度、高度的直接作用相对较小;盖度、高度均通过地上生物量对土壤的水、盐、有机质含量产生较强的间接作用效果.植被的地上生物量是影响土壤表层水、盐、有机质含量的最主要因素.

[Objective] The relationship between salinification and alkaline of topsoil and vegetation cover was analyzed to provide scientific basis for the prevention and control of soil secondary salinization in this area.[Methods] Plant height,aboveground biomass of glycyrrhiza community and soil moisture,pH value,salt content in soil surface(0-5 cm) were measured.The relationships between indexes of vegetation characteris tics and physical and chemical indexes of topsoil through measuring vegetation coverage were analyzed.[Results] With the extension of growing years,the vegetation coverage,plant height and aboveground biomass of Glycyrrhiza uralensis appeared an increasing trend.On the contrary,salt content and pH value of topsoil indicated a decreasing trend.Correlation analysis displayed,there was a negative relation between soil salt content and pH value of topsoil and all indexes of vegetation characteristics.Correlation coefficients ranked as vegetation coverage＞ plant height＞ aboveground biomass.Regression analysis indicated,salt content and pH value of topsoil and indexes of vegetation characteristics all showed a negative linear relation.When coverage,height and aboveground biomass of Glycyrrhiza uralensis vegetation each increased one unit,pH values of topsoil decreased 0.012,0.011 and 0.002,salt content of topsoil decreased 0.108,0.107 and 0.015 g/kg.[Conclusion] Vegetation significantly influenced salt content and pH value of topsoil.The most influence index is vegetation.When only considering the restraining of soil salt,those crops with more branches and leaves,and with high stalks should be selected.

To explore effects and mechanisms of liqorice ( Glycyrrhiza Uralensis) vegetation conserving soil nutrients and reducing wind erosion, analysis was done of the liqorice vegetation cover for characteristic indices and of the soil 0-5 cm under the cover for soil nutrient conservation and effect on wind erosion reduction. Results show that with the liqorice vege?tation growing on, coverage, height and above ground biomass of the vegetation, and organic carbon( OC) , available N, P and K contents in the topsoil all increased, while wind erosion and bulk density decreased ( P<0?05) . Correlation analysis indicates that characteristic indices were significantly and positively related to soil nutrients ( P<0?05) , showing an order of vegetation coverage>height>aboveground biomass in terms of correlation coefficient. Regression analysis demonstrates that for every 1% of increase in vegetation coverage, the content of OC, available N, P and K in the topsoil increased 0?038 g·kg-1, 0?052 mg·kg-1, 0?113 mg·kg-1 and 0?971 mg·kg-1, respectively. Obviously, the adoption of the practice of maintaining vegetation coverage on farmlands of wind erosion stricken regions of Northwest China, may on the one hand, reduce wind erosion of the surface soil and hence the loss of soil nutrients, and on the other hand, increase the amount of litters and hence content of soil nutrient, of which the joint effects will eventually reduce the loss of soil nutrients correspondingly.

OBJECTIVE:To research the relationship between the seedling grade of Glycyrrhiza uralensis and the biomass accumulation, yield and quality of product, so as to provide basis for establishing seedling standard.METHODS:The weight of single seedling root was measured and the seedlings were divided into three grades by the clustering analysis. The different grade treatments of seedlings were made to conduct field trials and laboratory experiments.RESULTS:The weight of the whole plant and dry root in growth period of grades 1 and 2 (the weight of single root greater than 10.0 g) were larger than grade 3, and the yield was also the case. The root of Glycyrrhiza uralensis, growing for three years, of grades 1 and 2 contained higher contents of active compounds than grade 3 and the content of glycyrrhizin and liquiritin in the root of Glycyrrhiza uralensis of all treatments were higher than the standard of Chinese Pharmacopoeia (2010 edition).CONCLUSION:The plant from the grades 1 and 2 seedlings with larger growth increment,higher output and better quality is the best seedling in cultivation.

The changes of soil physical properties and surface microenvironment in Glycyrrhiza uralensis field were studied using the sequence instead of temporal.The results showed that with the extension of growing time,the coverage,plant height and aboveground biomass of Glycyrrhiza uralensis population showed increasing trend.The aerodynamic roughness of soil surface increased by 12-55 times,the soil moisture content in topsoil(0-5cm) increased by 27%-148%; on the contrary,the soil bulk density and soil mean grain size decreased by0.7%-19.4% and 33.1%-48.8% respectively,compared with barren cultivated land.In conclusion,planting Glycyrrhiza uralensis could increase roughness and humidity of the surface,soil moisture content and porosity,and the values of these indices appeared increasing trend with aboveground biomass increasing.It was suggested that ecological environment and economic benefits would be improved,when Glycyrrhiza uralensis was planted in sandy cultivated land in northwest China.

The present study determined erosion-resistance effects of fields planted with Glycyrrhiza uralensis through measuring soil moisture content,aerodynamic roughness of soil surface and soil loss.The above ground biomass of G.uralensis community significantly increased with the extension of growing years.The aerodynamic roughness of soil surface increased by 12~55times and soil moisture content in soil surface(0-5cm)increased by 27%~148%after G.uralensis planted.Soil wind erosion in G.uralensis lands significantly decrease by 16%~83%than that of barren land.The above ground biomass positively correlated with roughness length and soil moisture content and negatively correlated with soil erosion.The possible mechanism of wind erosion resistance by planting G.uralensis was that surface of cultivated land was covered by the above ground dry branches and fallen leaves of G.uralensis which increased roughness of soil surface and topsoil moisture content,decreased the wind speed on soil surface and increased the starting wind speed for soil sand grain.

采用TPS-2型光合测定仪对乌拉尔甘草（Glycyrrhiza uralensis）、胀果甘草（G.inflata）、刺果甘草（G.pallidiflora）、光果甘草（G.glabra）和黄甘草（G.eurycarpa）栽培植株上部叶片光合日变化特征进行研究,对光合色素、形态和生物量进行测定和分析,并比较上述指标的种间差异,为甘草栽培技术和综合利用模式提供科学依据。结果表明:（1）各种的叶片净光合速率、蒸腾速率、水分利用率和气孔导度日变化均呈"双峰"型,峰值分别出现于12:00和16:00,14:00存在明显的光合"午休"现象;叶片细胞间隙CO2浓度日变化均呈"W"型,峰值分别出现于08:00、14:00和18:00,低谷出现于12:00和16:00;叶片温度日变化均呈"倒V"型,峰值出现于14:00,低值出现于08:00和18:00;且各种上述指标存在不同程度的差异性。（2）各种的叶片叶绿素a、叶绿素b、类胡萝卜素含量及叶绿素总量和叶绿素a含量/叶绿素b含量大小各不相同,其中叶绿素a含量存在种间显著差异。（3）各种的主茎分枝数、叶片数、主茎高、主根长、地上部分干重、地下部分干重及总生物量存在一定的差异性。（4）净光合速率日均值与气孔导度、蒸腾速率、水分利用效率、叶面温度日均值和叶绿素a含量正相关,相关系数分别为0.984、0.977、0.927、0.909和0.933,与胞间CO2浓度负相关,相关系数为-0.972。乌拉尔甘草具有较高的光合性能和经济产量,适于在该区大规模推广栽培;胀果甘草、光果甘草和刺果甘草总生物量较大,除地下部分药用外,应加强对其地上部分的开发利用;黄甘草光合性能、经济产量和总生物量均显著低于其他种,但地上部分鲜嫩,建议对其加强畜牧业方面的开发利用。

We applied tissue culture technology,stems with axillaries buds from aseptic seedling of Radix Glycyrrhiza,researched the effect on induction of aseptic seedling of Radix Glycyrrhiza and rapid propagation technique with different concentrations of 6-BA.The results indicated that the best culture medium was MS,the most suitable lengths of stem segments was 0.7 cm,the best concentration was 1 mg/L 6-BA,the most suitable cultivation condition was MS+1 mg/L 6-BA+0.1 mg/L NAA,lengths of stem segments was 0.7 cm,culture first generation needed 20 days,increment multiple was 7,one Radix Glycyrrhiza seed could become 117 649 aseptic seeding after half-year cultivation.