Root physiological responses can explain the effects of short-term plant-plant interactions on growth of two subalpine coniferous species

Root functional traits play an important role in nutrient acquisition of plants, affecting the outcome of plant-plant interactions. However, few studies have comprehensively investigated the plastic responses of plant root traits to plant-plant interactions. A pot experiment was conducted to quantify the effects of intraspecific and interspecific interactions on seedlings growth and multiple root traits of two coniferous species, Picea asperata and Abies faxoniana. The results showed that plant-plant interactions changed root physiology of two species but did not affect their root system, morphological, architectural and biotic traits. Intraspecific interaction resulted in lower root N content and stronger resource competition than under interspecific interaction. Under intraspecific interaction, P. asperata had lower root vigor and nitrate reductase activity, which impeded the acquisition and utilization of the limited resources, and thus resulted in marginally decreased total biomass; while total biomass for A. faxoniana was not significantly affected. Under interspecific interaction, the high total biomass of A. faxoniana could be explained by rhizosphere interactive effects and reduced metabolic (carbon and nitrogen) costs due to lower root exudative outputs. Our results demonstrate that root physiological responses can explain the effects of short-term plant-plant interactions on plant growth.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author