Vertical distribution pattern of mixed root systems of desert plants Reaumuria soongarica and Salsola passerina under different environmental gradients

AimsHow plant species interaction changes along environmental gradients has remained a hot issue in studies of species coexistence and biodiversity maintenance.This study was conducted to determine the responses of root systems to drought stress in desert Reaumuria soongarica-Salsola passerina communities, in order to better understand the interspecific relationships of plant communities in response to environmental stresses.Methods Monocultural and mixed R. soongarica and S. passerina communities were selected in Lingwu, Zhangye and Jiuquan, representing a drought stress gradient varying from desert steppe habitat to extreme desert habitat.Measurements were made on the vertical structures of root traits including specific root length (SRL) and specific root surface area (SRA).Root samples were collected by trench method by layers.Important findings Both SRL and SRA had greater values in mixed R. soongarica-S.passerina communities than in monocultural communities of either species within given habitat, suggesting a mutually beneficial relationship between the two species and the enhanced ability of roots to absorb soil nutrients and water when in mixture.Reaumuria soongarica had deeper roots and a greater root extinction coefficient in vertical distribution than S. passerina in either monocultural or mixed communities, indicating the belowground niche segregation 张素彦 于2018年6月