Microplastic accumulation caused by traditional plastic mulching can disturb plant nutrient-mining strategies.Biodegradable plastics may reduce these risks.However,the different effects of traditional and biodegradabl...Microplastic accumulation caused by traditional plastic mulching can disturb plant nutrient-mining strategies.Biodegradable plastics may reduce these risks.However,the different effects of traditional and biodegradable microplastics on agroecosystems and optimal microplastic type for crop-soil systems remain largely unknown.A pot experiment was performed to identify the mechanisms underlying the effects of traditional[polypropylene(PP)and polyethylene(PE)]and biodegradable[polycaprolactone(PCL)and polyadipate/butylene terephthalate(PBAT)]microplastics at 0%,0.1%and 1%(w/w)in a pea-soil ecosystem.Traditional microplastics caused greater carbon allocation to shoots,while PBAT did not significantly alter dissolved organic-carbon content.NH_(4)^(+)-N increased with 1%(w/w)PP whereas NO_(3)^(–)-N decreased owing to enhanced N-acetylglucosaminidase activity with 0.1%and 1%PP and PE,and 1%PBAT during pea growth.Biodegradable microplastics enhanced microbial biomass carbon,nitrogen and phosphorus,whereas traditional microplastics gave inconsistent results.Microplastics increased the complexity of bacterial and fungal networks and impacted ecosystem functions because they may serve as labile carbon resources for soil microorganisms,stimulating organic matter decomposition.However,once labile carbon in native soils is depleted,inadequate fresh labile carbon from root exudates fails to alleviate microbial carbon limitations,resulting in peas competing with microorganisms for scarce nitrogen resources to promote its growth.展开更多
Background Establishing mixed-species plantations is increasingly recognized as an important silvicultural measure because they are more productive than monocultures.This over-yielding is attributed to the complementa...Background Establishing mixed-species plantations is increasingly recognized as an important silvicultural measure because they are more productive than monocultures.This over-yielding is attributed to the complementary resource use between component tree species,yet it remains largely unknown whether and how component tree species adjust nutrient acquisition and utilization strategies to achieve complementary nutrient use.Here,we measured soil nitrogen(N)availability and transformation rates,leaf N resorption efficiency and proficiency,and nine root morphological,physiological and mycorrhizal traits tightly related to N acquisition in 20-year-old pure and mixed stands of Pinus sylvestris var.mongolica(Mongolian pine)and Populus simonii(Simon poplar),northeast China.Results Tree species mixing had negative effects on soil nitrate concentration and net N mineralization rate,but had positive effects on absorptive fine root biomass.Compared to growing alone,Mongolian pine in mixed stands had higher leaf N resorption efficiency,and produced more absorptive fine roots with more-efficient morphological features in nutrient acquisition characterized by higher specific root length and lower root tissue density.Additionally,Simon poplar had greater root length density,root area index,and the relative abundance of ectomycorrhizal fungi with genetic potential to produce class II peroxidases in mixed than pure stands.Conclusions These findings highlight that component species express high plasticity in nutrient acquisition and utilization traits in response to tree species mixing,and suggest that this high plasticity could be responsible for the over-yielding of mixed-species plantations.展开更多
基金supported by National Natural Science Foundation of China(42407458 and 42307420)China Agriculture Research System Food-Legumes(CARS-08-G-09)the UK Natural Environment Research Council,the Global Challenges Research Fund(NE/V005871/1)and the K.C.Wong Magna Fund at Ningbo University.
文摘Microplastic accumulation caused by traditional plastic mulching can disturb plant nutrient-mining strategies.Biodegradable plastics may reduce these risks.However,the different effects of traditional and biodegradable microplastics on agroecosystems and optimal microplastic type for crop-soil systems remain largely unknown.A pot experiment was performed to identify the mechanisms underlying the effects of traditional[polypropylene(PP)and polyethylene(PE)]and biodegradable[polycaprolactone(PCL)and polyadipate/butylene terephthalate(PBAT)]microplastics at 0%,0.1%and 1%(w/w)in a pea-soil ecosystem.Traditional microplastics caused greater carbon allocation to shoots,while PBAT did not significantly alter dissolved organic-carbon content.NH_(4)^(+)-N increased with 1%(w/w)PP whereas NO_(3)^(–)-N decreased owing to enhanced N-acetylglucosaminidase activity with 0.1%and 1%PP and PE,and 1%PBAT during pea growth.Biodegradable microplastics enhanced microbial biomass carbon,nitrogen and phosphorus,whereas traditional microplastics gave inconsistent results.Microplastics increased the complexity of bacterial and fungal networks and impacted ecosystem functions because they may serve as labile carbon resources for soil microorganisms,stimulating organic matter decomposition.However,once labile carbon in native soils is depleted,inadequate fresh labile carbon from root exudates fails to alleviate microbial carbon limitations,resulting in peas competing with microorganisms for scarce nitrogen resources to promote its growth.
基金supported by the National Natural Science Foundation of China(No.32471838)the National Key Research and Development Program of China(No.2023YFF1304201)
文摘Background Establishing mixed-species plantations is increasingly recognized as an important silvicultural measure because they are more productive than monocultures.This over-yielding is attributed to the complementary resource use between component tree species,yet it remains largely unknown whether and how component tree species adjust nutrient acquisition and utilization strategies to achieve complementary nutrient use.Here,we measured soil nitrogen(N)availability and transformation rates,leaf N resorption efficiency and proficiency,and nine root morphological,physiological and mycorrhizal traits tightly related to N acquisition in 20-year-old pure and mixed stands of Pinus sylvestris var.mongolica(Mongolian pine)and Populus simonii(Simon poplar),northeast China.Results Tree species mixing had negative effects on soil nitrate concentration and net N mineralization rate,but had positive effects on absorptive fine root biomass.Compared to growing alone,Mongolian pine in mixed stands had higher leaf N resorption efficiency,and produced more absorptive fine roots with more-efficient morphological features in nutrient acquisition characterized by higher specific root length and lower root tissue density.Additionally,Simon poplar had greater root length density,root area index,and the relative abundance of ectomycorrhizal fungi with genetic potential to produce class II peroxidases in mixed than pure stands.Conclusions These findings highlight that component species express high plasticity in nutrient acquisition and utilization traits in response to tree species mixing,and suggest that this high plasticity could be responsible for the over-yielding of mixed-species plantations.
