Evaluation of drought resistance of 36 Indigofera pseudotinctoria germplasm resources
[Objective]The present paper aimed to analyze the impact of varying degrees of drought stress treatments on the physiological pa-rameters of Indigofera pseudotinctoria,preliminarily evaluate the drought-resistant physiological responses of these materials,and provide a foundational reference for the selection and genetic improvement of drought-resistant germplasm in Ⅰ.pseudotinctoria.[Method]36 wild Ⅰ.pseudotinctoria germplasm resources collected in Chongqing area were used as experimental materials.Pot cultivation was used to start drought treatment when Ⅰ.pseudotinctoria seedlings grew to the 90th day,and measure the content of osmoregulatory substances,relative wa-ter content,and antioxidant enzyme activity in the leaves of Ⅰ.pseudotinctoria under 0 days of stress(control group CK,the relative soil wa-ter content was 80％-85％of the field water capacity),7 days of stress(moderate drought,soil relative moisture content was 40％-50％of the field water capacity),and 14 days of stress(severe drought,soil relative moisture content was 20％-25％of the field water capaci-ty).Drought resistance coefficients,membership functions and cluster analysis were applied for a comprehensive evaluation of drought resist-ance.[Result]Under drought stress conditions,we observed a wide variation in physiological responses among the 36 Ⅰ.pseudotinctoria germplasms,leading to significant differences in their drought resistance capabilities.Comparative analysis of mean values for various param-eters showed that,in comparison to the control group,osmotic adjustment substances such as malondialdehyde(MDA),soluble protein(SP),and proline(Pro)increased with the severity of drought.The activities of superoxide dismutase(SOD),peroxidase(POD),and cat-alase(CAT)exhibited a'convex'trend as drought severity intensified,while relative water content(RWC)decreased with increasing drought stress.Among the seven parameters measured,peroxidase(POD)activity showed the largest coefficient of variation,while relative water content(RWC)displayed the smallest variation.Using membership function analysis,comprehensive D-value assessment,and cluster analysis,we categorized the drought resistance of the 36 Ⅰ.pseudotinctoria germplasms into two distinct groups:Drought-resistant(compri-sing 8 germplasms)and sensitive(comprising 28 germplasms).Further examination of physiological indicators between these two groups re-vealed that drought-resistant germplasms exhibited higher antioxidant enzyme activity and osmotic adjustment substance Pro content compared to their sensitive counterparts.[Conclusion]Under drought stress conditions,the physiological responses of the 36 Ⅰ.pseudotinctoria germ-plasm resources displayed significant diversity and variation.Among the 36 Ⅰ.pseudotinctoria germplasms,8 germplasms were classified as drought-resistance by a comprehensive evaluation analysis.
Indigofera pseudotinctoriaDrought stressEvaluation of germplasm resourceDrought resistancePhysiological response
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