| 1 | Effect of nitrogen and phosphorus addition on leaf nutrient concentrations and nutrient resorption efficiency of two dominant alpine grass species显示文摘Nitrogen(N)and phosphorus(P)are two essential nutrients that determine plant growth and many nutrient cycling processes.Increasing N and P deposition is an important driver of ecosystem changes.However,in contrast to numerous studies about the impacts of nutrient addition on forests and temperate grasslands,how plant foliar stoichiometry and nutrient resorption respond to N and P addition in alpine grasslands is poorly understood.Therefore,we conducted an N and P addition experiment(involving control,N addition,P addition,and N+P addition)in an alpine grassland on Kunlun Mountains(Xinjiang Uygur Autonomous Region,China)in 2016 and 2017 to investigate the changes in leaf nutrient concentrations(i.e.,leaf N,Leaf P,and leaf N:P ratio)and nutrient resorption efficiency of Seriphidium rhodanthum and Stipa capillata,which are dominant species in this grassland.Results showed that N addition has significant effects on soil inorganic N(NO_(3)^(-)-N and NH_(4)^(+)-N)and leaf N of both species in the study periods.Compared with green leaves,leaf nutrient concentrations and nutrient resorption efficiency in senesced leaves of S.rhodanthum was more sensitive to N addition,whereas N addition influenced leaf N and leaf N:P ratio in green and senesced leaves of S.capillata.N addition did not influence N resorption efficiency of the two species.P addition and N+P addition significantly improved leaf P and had a negative effect on P resorption efficiency of the two species in the study period.These influences on plants can be explained by increasing P availability.The present results illustrated that the two species are more sensitive to P addition than N addition,which implies that P is the major limiting factor in the studied alpine grassland ecosystem.In addition,an interactive effect of N+P addition was only discernable with respect to soil availability,but did not affect plants.Therefore,exploring how nutrient characteristics and resorption response to N and P addition in the alpine grassland is important to understand nutrient use strategy of plants in terrestrial ecosystems. | LIU Yalan LI Lei LI Xiangyi YUE Zewei LIU Bo | 2021 | Journal of Arid Land2021，13，10： | 1 |
| 2 | Response mechanism of Chlamydomonas reinhardtii to nanoscale bismuth oxyiodide(nano-BiOI):Integrating analysis of mineral nutrient metabolism and metabolomics显示文摘Nanoscale bismuth oxyiodide(nano-BiOI) is widely studied and applied in environmental applications and biomedical fields, with the consequence that it may be deposited into aquatic environments. However, the impact of nano-Bi OI on aquatic ecosystems, especially freshwater microalga, remains limited. Herein, the nano-Bi OI was synthesized and its response mechanism towards microalga Chlamydomonas reinhardtii was evaluated. Results showed that a low concentration of nano-Bi OI(5 mg/L) could stimulate algal growth at the early stage of stress. With the increase in concentration, the growth rate of algal cells was inhibited and showed a dose effect. Intracellular reactive oxygen species(ROS) were significantly induced and accompanied by enhanced lipid peroxidation, decreased nonspecific esterase activity, and significantly upregulated glutathione S-transferase activity(GST) activity. Mineral nutrient metabolism analysis showed that nano-Bi OI significantly interfered with the mineral nutrients of the algae. Non-targeted metabolomics identified 35 different metabolites(DEMs, 22 upregulated, and 13 downregulated) under 100 mg/L Bi OI stress.Metabolic pathway analysis demonstrated that a high concentration of nano-Bi OI significantly induced metabolic pathways related to amino acid biosynthesis, lipid biosynthesis,and glutathione biosynthesis, and significantly inhibited the sterol biosynthesis pathway.This finding will contribute to understanding the toxicological mechanisms of nano-Bi OI on C. reinhardtii. | Yan Huang Jinlong Lai Yang Huang Xuegang Luo Xu Yang Zewei Liu Yue Duan Chen Li | 2022 | Journal of Environmental Sciences2022，34，11： | 0 |
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