| Leymus chinensis is an important dominant and strong species in the steppe region of Eurasia.It belongs to the perennial herb of Leymus Hochst..Due to its excellent forage quality,strong stress tolerance and resistance,Leymus chinensis plays an important role in the restoration of degraded grassland,planting of artificial grassland,prevention and control of water and soil erosion,and forage production and processing.In recent decades,grassland degradation in China has been serious,vegetation community degradation and succession have taken place,and productivity has decreased significantly.At the same time,with the change of environment,especially the aggravation of drought in the degraded steppe,the diversity of germplasm resources of Leymus chinensis is facing serious threat,and its important ecological role is gradually reduced with the degradation and succession of steppe.Based on this,this study used 48 wild Leymus chinensis germplasm resources collected from different regions of the world in 2014 as research materials.Based on the homogenous garden experiment,the phenotypic variation of Leymus chinensis from different geographical sources was analyzed and its variation characteristics were summarized.At the same time,the soil nutrient characteristics under the influence of different germplasm resources of Leymus chinensis were studied,and the correlation between the variation of Leymus chinensis characters and soil characters was clarified.The main conclusions are as follows:(1)There was great phenotypic variation among the germplasm resources of wild Leymus chinensis from different geographical sources,showing rich genetic diversity.The germplasm of Leymus chinensis with higher coefficient of morphological variation were YC23,YC28 and YC48,while the germplasm of Leymus chinensis with lower coefficient of morphological variation were YC46,YC05 and YC38.The morphological characters with higher coefficient of variation were stem weight/leaf weight,leaf weight and stem weight,while the morphological characters with lower coefficient of variation were leaf length,leaf width and plant height.(2)Principal component analysis of morphological traits showed that the cumulative variance contribution rate of the four principal components was 84.680%,which represented most of the information of the original indicators.The first principal component mainly reflects the characteristics of plant height of Leymus chinensis,representing the most original information;the second principal component mainly reflects the information of leaf weight;the third principal component mainly reflects the geometric characteristics of leaves;the fourth principal component mainly reflects the characteristics of the whole plant,representing relatively little information.According to the cluster analysis of morphological characters,48 germplasm resources of Leymus chinensis were grouped into 4 groups at the Euclidean distance coefficient 1.6,and the comprehensive comparison of morphological characters of4 groups of Leymus chinensis showed that the first and second groups of Leymus chinensis performed well.The morphological traits had the most significant effect on the aboveground biomass of Leymus chinensis,while the effect on the underground root biomass was small.Plant height,stem length and internode number were the most significant factors affecting aboveground biomass of Leymus chinensis.(3)Leymus chinensis had a better improvement effect on soil,and the effects of different geographical sources of Leymus chinensis on soil nutrient content were significantly different.Among them,the Leymus chinensis materials with the best performance on soil improvement were YC07,YC24,YC04,YC39 and YC46.According to the cluster analysis of soil nutrients,Leymus chinensis could be divided into three groups.The results showed that the first group of Leymus chinensis had a better effect on soil nutrients,which was basically consistent with the results of principal component score analysis.At the same time,the effect of Leymus chinensis increased soil C:P and N:P,and the soil ecological stoichiometry under the influence of different sources of Leymus chinensis showed significant differences.(4)There were general simple correlations among morphological traits and soil traits,and significant canonical correlations between morphological traits and biomass traits,and between morphological traits and soil traits.Plant weight,plant height and fresh grass weight played an important role in the typical correlation between morphological traits and biomass traits.The stem weight,leaf weight and soil organic matter were the main components of the typical correlation between morphological traits and soil traits. |
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