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Dry-hot stress significantly reduced the nitrogenase activity of epiphytic cyanolichen 

作者: Liu S
刊物名称: Science of the Total Environment
论文题目英文: Dry-hot stress significantly reduced the nitrogenase activity of epiphytic cyanolichen
年: 2018 APR
卷: 619
页: 630-637
联系作者: liu WY
影响因子: 4.900
摘要: Nitrogen (N) fixed by epiphytic cyanolichens (i.e. lichens that contain cyanobacterial symbionts) is thought to be themost important resource of this nutrient in somenatural forest ecosystems.Although a great deal of work has been carried out to evaluate the biomass of this group aswell as its contribution to ecosystem N budgets, empirical studies are needed to confirm the N input responses by cyanolichens under climate change conditions (dry-hot stress) as well as to determine the factors that control this process. We simulated climate change conditions by transplanting Lobaria retigera, a common cyanolichen in the area, to lower elevations, and measured nitrogenase activity in response towarmer and drier conditions. In addition, we conducted a series of laboratory and greenhouse experiments to determine the dominant factors influencing nitrogenase activity in this species. The results of this study show thatmean annual nitrogenase activity at the higher site was 1.5 and 2.4 times that at the simulated warmer and drier (middle and lower) sites, respectively. Combining laboratory experimental conclusions,we show that thalluswater content is a key factor determining the nitrogenase activity of L. retigera in early transplantation while insufficient carbon storage resulting froma combination ofwarming and desiccationwas likely responsible for reducing nitrogenase activity in latermonths of the transplant experiment. The results of this study imply that the negative impact of climate change (dry-hot stress) on ecosystems not only impacts the distribution and growth of species, but also nutrient circles and budgets. ? 2017 Elsevier B.V. All rights reserved.
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