大麦与谷类科学

为了探究干旱胁迫条件下不同基因型春小麦种质苗期的抗旱性，以不同来源的15份春小麦种质为材料，在不同程度的干旱胁迫下，测定根长、根体积、根表面积、苗鲜质量、苗长、超氧化物歧化酶活性等指标，综合运用聚类分析、隶属函数分析、相关性分析和主成分分析等多种方法，对春小麦种质的抗旱性进行全面、系统的评价。结果表明：15份春小麦种质之间的抗旱性差异较大；在轻度干旱胁迫下，各指标的变异系数范围为7.60%～39.05%；在重度干旱胁迫下，变异系数范围为8.51%～37.89%；对照条件下变异系数范围为7.96%～47.84%。相比于对照，所有春小麦种质在干旱胁迫（轻度干旱胁迫和重度干旱胁迫）下的苗长、叶绿素含量、苗鲜质量均有不同程度的降低，过氧化物酶（POD）、过氧化氢酶（CAT）和超氧化物歧化酶（SOD）活性及丙二醛（MDA）含量均有不同程度的增加。利用主成分分析，13个苗期指标被划分为4个主成分，轻度干旱胁迫下4个主成分贡献率分别为45.98%、16.18%、11.71%、8.69%，重度干旱胁迫下4个主成分贡献率分别为47.88%、14.30%、12.74%、8.72%。依托各生理指标的抗旱系数，并结合主成分分析过程中确定的主成分特征向量，经过系统运算，最终确定综合抗旱系数D值。依据D值对15个春小麦种质抗旱性进行排序，同时依据D值进行聚类分析，将供试种质在轻度干旱胁迫和重度干旱胁迫下各分为4个群体。筛选出强抗旱春小麦种质1份（甘春0058），干旱敏感型种质2份（甘春33号、IBWSN 93），确定了苗鲜质量、苗干质量、根鲜质量、根干质量、根长、根表面积作为春小麦种质苗期抗旱性评价的有效指标。

To explore the drought resistance of different genotypes of spring wheat germplasm at the seedling stage under drought stress, 15 spring wheat germplasm resources from different sources were used as materials. Under different degrees of drought stress,the indicators including root length, root volume, root surface area, seedling fresh weight, seedling length, and superoxide dismutase(SOD) were determined. Multiple methods such as cluster analysis, membership function analysis, correlation analysis, and principal component analysis(PCA) were comprehensively applied to conduct a comprehensive and systematic evaluation of the drought resistance of spring wheat germplasm. There were significant differences in drought resistance among the 15 spring wheat germplasm resources. Under mild drought stress, the coefficient of variation(CV) of each indicator ranged from 7.60% to 39.05%. Under severe drought stress, the CV ranged from 8.51% to 37.89%, and under control conditions, the CV ranged from 7.96% to 47.84%. Compared with the control, seedling length, chlorophyll content, and seedling fresh weight of all spring wheat germplasm decreased to varying degrees under drought stress(both mild and severe), while the activities of peroxidase(POD), catalase(CAT), and SOD as well as the content of malondialdehyde(MDA) increased to varying degrees. Through PCA, 13 seedling-stage indicators were divided into4 principal components. The contribution rates of the 4 principal components under mild drought stress were 45.98%, 16.18%,11.71%, and 8.69% respectively, while those under severe drought stress were 47.88%, 14.30%, 12.74% and 8.72% respectively.Based on the drought resistance coefficients of each physiological indicator and combined with the principal component eigenvectors determined in the PCA process, the comprehensive drought resistance coefficient(D value) was finally obtained through systematic calculations. The drought resistance of the 15 spring wheat germplasm was ranked according to the D value, and cluster analysis based on the D value divided the tested germplasm into 4 groups respectively under mild and severe drought stress. One highly drought-resistant germplasm(Ganchun 0058) and two drought-sensitive germplasm(Ganchun No.33, IBWSN 93) were screened out.Seedling fresh weight, seedling dry weight, root fresh weight, root dry weight, root length, and root surface area were identified as effective indicators for evaluating the drought resistance of spring wheat germplasm at the seedling stage.