干旱胁迫对4种委陵菜属植物形态与光合生理的影响OA

[Objective]To evaluate the drought resistance of four Potentilla species and determine their drought-tolerance thresholds,thereby providing a theoretical basis for their application in landscape greening projects in the northern China.[Method]Four Potentilla species(P.multicaulis,P.multifida var.ornithopoda,P.conferta,and P.fragarioides)were subjected to drought stress induced by natural dehydration.Morphological and photosynthetic physiological parameters were measured during the drought treatment,and the drought resistance of the four taxa was comprehensively evaluated.[Result]With increasing drought stress,leaf relative water content,net photosynthetic rate,stomatal conductance,and transpiration rate decreased in all four Potentilla taxa,whereas relative electrical con-ductivity,root-shoot ratio,and intercellular CO₂ concentration increased.Morphologically,the plants reduced water loss and alleviated drought-induced damage by reducing the number of leaves and shrinking the leaf area,while in-creasing the root-to-shoot ratio.After 30 days of continuous drought stress,the comprehensive drought-resistance ranking of the four Potentilla species was P.multifida var.ornithopoda>P.fragarioides>P.multicaulis>P.con-ferta.[Conclusion]P.fragarioides and P.multifida var.ornithopoda exhibited sustained drought tolerance for 25-30 days following irrigation to full water saturation,indicating their suitability for landscapes characterized by low soil wa-ter-holding capacity or low-maintenance management.In contrast,P.multicaulis and P.conferta displayed limited drought tolerance,with post-irrigation drought endurance thresholds of no more than 15 days.Therefore,these two taxa are less suitable for water-efficient groundcover applications in xeriscaping projects.