Plants adapt to the limitation of soil phosphorus(P)induced by nitrogen(N)deposition through a complex interaction of various root and leaf functional traits.In this study,a pot experiment was conducted to explore the...Plants adapt to the limitation of soil phosphorus(P)induced by nitrogen(N)deposition through a complex interaction of various root and leaf functional traits.In this study,a pot experiment was conducted to explore the effects of different levels of N addition(control,low N[LN]:25 kg N ha^(-1) yr^(-1),high N[HN]:50 kg N ha^(-1) yr^(-1))on tree growth,leaf nutrient content,foliar P fractions and root characteristics of two dominant tree species,the pioneer species Salix rehderiana Schneid and the climax species Abies fabri(Mast.)Craib,in a subalpine forest in southwestern China.The results demonstrated that LN addition had a minimal impact on leaf N and P contents.Conversely,HN addition significantly decreased the leaf P content in both species.Salix rehderiana exhibited more pronounced increases in specific root length and specific root area under P deficiency triggered by HN addition when compared with A.fabri.In contrast,A.fabri showed weaker morphological responses to N addition but had a higher proportion of foliar P to metabolic P,as well as higher root exudates rate and root phosphatase activity in response to HN addition.Abies fabri employs a synergistic approach by allocating a greater amount of leaf P to metabolite P and extracting P from the soil through P-mobilizing exudates and root phosphatase activity,while S.rehderiana exhibits higher flexibility in modifying its root morphology in response to P limitation induced by HN addition.This study provides insights into subalpine tree species adaptation to N-induced P limitation,emphasizing its significance for guiding forest management and conservation in the context of global climate change.展开更多
Aims: Plant roots show various functional strategies in soil phosphorus(P) acquisition. Under limited soil phosphatase activity, P deficiency is the main concern, and roots either invest carbon(C) to produce higher le...Aims: Plant roots show various functional strategies in soil phosphorus(P) acquisition. Under limited soil phosphatase activity, P deficiency is the main concern, and roots either invest carbon(C) to produce higher levels of phosphatase or establish more symbioses with mycorrhizal fungi. However, these strategies and their interactions are not clear. Furthermore, few studies have investigated trade-offs of functional traits in woody species associated with different types of mycorrhizal partners.Methods: Here we examined the abilities to release acid phosphatase(AP) and the colonization ratio by arbuscular and ectomycorrhizal fungi for fine roots of 15 woody species growing in a tropical common garden in Xishuangbanna, China. We also measured acid phosphatase activities of bulk soils under the canopy of target trees.Results: Soil and root AP activities exhibited a positive correlation, indicating that roots actively produced AP to acquire P even bulk soil AP was increasing. We found a significantly negative correlation(P=0.02) between mycorrhizal colonization ratio and root-released AP activity across target species, reflecting a trade-off between these two P acquisition strategies.Conclusions: Our findings suggest a trade-off of resource allocation between these two strategies at both species and individual levels, and provide information on the overall mechanism of P acquisition by fine roots that they either ‘do it by themselves’ or ‘rely on mycorrhizal partners’. These two strategies might be integrated into the collaboration gradient of the root economics space.展开更多
The mechanisms of plant adaptation to environmental gradients have been the focus of ecological research,with environmental stresses driving coordinated or differentiated regulation of plant functional traits.Plant re...The mechanisms of plant adaptation to environmental gradients have been the focus of ecological research,with environmental stresses driving coordinated or differentiated regulation of plant functional traits.Plant resource acquisition involves root trait plasticity and mycorrhizal symbiosis.However,root trait plasticity along precipitation gradients and root-mycorrhizal trade-offs remain unclear.We conducted community surveys along a west-east precipitation gradient in four natural grassland communities(alpine desert steppe,alpine steppe,alpine meadow steppe and alpine meadow)on the plateau in northern Xizang Plateau.Six key root traits(root diameter,RD;root dry matter content,RDMC;root tissue density,RTD;specific root length,SRL;root branching intensity,RBI;and root length colonization percentage,RLC)were measured in 18 alpine plant species to investigate the coordination and trade-offs between root traits and mycorrhizal fungi along the precipitation gradient.Our results showed community-level declines in RDMC,RD,RTD and RLC with increasing precipitation,contrasting with elevated RBI and SRL.Functional groups exhibited distinct patterns:grasses and legumes demonstrated root-mycorrhizal trade-offs,sedges displayed synergy and forbs showed inconsistent responses.Divergent trends in plant root traits and mycorrhizal fungi were observed at the species level.Alpine plants in humid eastern meadows favored root elongation,while those in arid western desert steppe relied on radial growth and mycorrhizal fungal cooperation for resource acquisition.These findings highlight varied root absorption strategies among alpine plants along environmental gradients,supporting the importance of ecological niche diversification in maintaining alpine ecosystem diversity and stability.展开更多
How sex-related root traits and soil microbes and their interactions respond to drought remains unclear.Here,we investigated how fine root traits and the composition of rhizosphere microbial communities in Populus eup...How sex-related root traits and soil microbes and their interactions respond to drought remains unclear.Here,we investigated how fine root traits and the composition of rhizosphere microbial communities in Populus euphratica females and males respond to drought in concert in 17-year-old plantations.Females increased specific root length(SRL)in response to drought.However,males showed no changes in their roots but significant increases in arbuscular mycorrhizal hyphal biomass and population of Gram-negative bacteria in the rhizosphere.Also,fungal symbiotroph communities associated with root systems in males differed from those in females under drought.We further demonstrated that the Gram-positive to Gram-negative bacteria ratios positively correlated with the SRL,while fungi to bacteria ratios were negatively correlated.Meanwhile,the relative abundance of symbiotrophs was negatively correlated with the SRL,while saprotroph abundance was positively correlated.Nevertheless,the relative abundance of symbiotrophs was positively correlated with the root carbon content(RCC).These findings indicate that microbial responses to drought depend highly upon the sex of the plant and microbial group and are related to root trait adjustments to drought.This discovery also highlights the role of plant-microbial interactions in the ecosystems of P.euphratica forest plantations.展开更多
Aims root systems play an essential role in grassland functioning in both acquisition and storage of resources.Nevertheless,root functional traits have not received as much attention as those measured on above-ground ...Aims root systems play an essential role in grassland functioning in both acquisition and storage of resources.Nevertheless,root functional traits have not received as much attention as those measured on above-ground organs,and little is known about their relations.our objec-tives were to test whether morphological and root system traits allowed identification of grass species’functional strategies and to determine whether a relation exists between above-and below-ground traits.Methods Functional traits of root tissues(specific root length,diameter,tissue density and nitrogen concentration),whole root systems(root mass,root length density,root mass percentage below a depth of 20 cm and fine root%)and two major leaf traits(specific leaf area and leaf dry matter content)were determined under field conditions and their rela-tions were analysed in eleven perennial temperate Poaceae species.Important Findings Canonical correspondence analysis along axis 1 revealed a gra-dient of species,from those with deep,dense and coarse root systems with a large root mass to those with shallow root sys-tems,thin roots and high specific root length;this suggests strong correlations among root traits.Correlations between specific root length and specific leaf area reveal two groups of species,which probably indicates different drought-tolerance capacities.root trait syndromes enable ranking grasses along a gradient from conservative-strategy species(from stressful habitats),which display a deep and coarse root system,to acquisitive species(from rich and moist meadows),which display a shallow and thin root system.although both types display similar above-ground strategies,drought-tolerant species have lower specific root lengths than drought-sensitive species,revealing more conservative root strategies.展开更多
Background Changes in precipitation alter soil moisture,thereby afecting the aboveground and belowground ecological processes.However,it remains unclear whether plant root systems alter these efects through rhizospher...Background Changes in precipitation alter soil moisture,thereby afecting the aboveground and belowground ecological processes.However,it remains unclear whether plant root systems alter these efects through rhizospheric processes.In this study,a precipitation control experiment was conducted in the alpine grassland of northern Xizang to simulate precipitation changes with a 50%decrease and 50%increase in precipitation.Nutrient and microbial biomass,root traits,and survival strategies in the rhizosphere and bulk soils of the dominant plant,Stipa purpurea,were analyzed for alterations under precipitation changes.Results Increased precipitation(IP)signifcantly decreased the rhizosphere soil total phosphorus and bulk soil ammonium nitrogen and increased the rhizosphere soil total potassium.Decreasing precipitation(DP)signifcantly increased the rhizosphere soil total potassium and decreased the bulk soil total potassium.DP signifcantly reduced microbial biomass carbon,nitrogen and phosphorus in rhizosphere soil,while IP signifcantly increased the bulk soil MBC:MBP,soil C:P imbalance,and soil N:P imbalance.Along the PC1 axis,where the contribution of the traits was relatively large,it was possible to defne the root economic spectrum.The root system of Stipa purpurea from the DP treatment was distributed on the conservative side of the economic spectrum,whereas that from the control and IP treatments were clustered on the acquisition side.Conclusions Increasing and decreasing precipitation mainly afected the contents of total phosphorus and total potassium in rhizosphere soil and the contents of ammonium nitrogen and total potassium in bulk soil of Stipa purpurea.The microbial biomass carbon,nitrogen and phosphorus were mainly afected by a decrease in precipitation.Decreasing precipitation signifcantly reduced microbial biomass carbon,nitrogen and phosphorus,but the rhizosphere MBC:MBN,MBC:MBP and MBN:MBP remained stable under the change of precipitation.Increasing precipitation exacerbated the C:P imbalance and N:P imbalance in bulk soil,and increased the demand for phosphorus by bulk microorganisms.Increased precipitation promoted root access to resources.The root system of Stipa purpurea in the context of precipitation changes was driven by rhizosphere nutrients and bulk microorganisms.This study is important for revealing plant–microbe–soil interactions in terrestrial ecosystems.展开更多
基金supported by Open Foundation of the Key Laboratory of Natural Resource Coupling Process and Effects(2023KFKTA005,2023KFKTB012)by the Science and Technology Research Program of Institute of Mountain Hazards and Environment,Chinese Academy of Sciences(IMHE-ZDRW-06).
文摘Plants adapt to the limitation of soil phosphorus(P)induced by nitrogen(N)deposition through a complex interaction of various root and leaf functional traits.In this study,a pot experiment was conducted to explore the effects of different levels of N addition(control,low N[LN]:25 kg N ha^(-1) yr^(-1),high N[HN]:50 kg N ha^(-1) yr^(-1))on tree growth,leaf nutrient content,foliar P fractions and root characteristics of two dominant tree species,the pioneer species Salix rehderiana Schneid and the climax species Abies fabri(Mast.)Craib,in a subalpine forest in southwestern China.The results demonstrated that LN addition had a minimal impact on leaf N and P contents.Conversely,HN addition significantly decreased the leaf P content in both species.Salix rehderiana exhibited more pronounced increases in specific root length and specific root area under P deficiency triggered by HN addition when compared with A.fabri.In contrast,A.fabri showed weaker morphological responses to N addition but had a higher proportion of foliar P to metabolic P,as well as higher root exudates rate and root phosphatase activity in response to HN addition.Abies fabri employs a synergistic approach by allocating a greater amount of leaf P to metabolite P and extracting P from the soil through P-mobilizing exudates and root phosphatase activity,while S.rehderiana exhibits higher flexibility in modifying its root morphology in response to P limitation induced by HN addition.This study provides insights into subalpine tree species adaptation to N-induced P limitation,emphasizing its significance for guiding forest management and conservation in the context of global climate change.
基金supported by funding from the National Natural Science Foundation of China(Nos.32001218,42141006 and 31988102).
文摘Aims: Plant roots show various functional strategies in soil phosphorus(P) acquisition. Under limited soil phosphatase activity, P deficiency is the main concern, and roots either invest carbon(C) to produce higher levels of phosphatase or establish more symbioses with mycorrhizal fungi. However, these strategies and their interactions are not clear. Furthermore, few studies have investigated trade-offs of functional traits in woody species associated with different types of mycorrhizal partners.Methods: Here we examined the abilities to release acid phosphatase(AP) and the colonization ratio by arbuscular and ectomycorrhizal fungi for fine roots of 15 woody species growing in a tropical common garden in Xishuangbanna, China. We also measured acid phosphatase activities of bulk soils under the canopy of target trees.Results: Soil and root AP activities exhibited a positive correlation, indicating that roots actively produced AP to acquire P even bulk soil AP was increasing. We found a significantly negative correlation(P=0.02) between mycorrhizal colonization ratio and root-released AP activity across target species, reflecting a trade-off between these two P acquisition strategies.Conclusions: Our findings suggest a trade-off of resource allocation between these two strategies at both species and individual levels, and provide information on the overall mechanism of P acquisition by fine roots that they either ‘do it by themselves’ or ‘rely on mycorrhizal partners’. These two strategies might be integrated into the collaboration gradient of the root economics space.
基金supported by the National Natural Science Foundation of China(42071066)the National Key Research and Development Program of China(2023YFF1304304)the West Light Foundation of the Chinese Academy of Sciences(2021).
文摘The mechanisms of plant adaptation to environmental gradients have been the focus of ecological research,with environmental stresses driving coordinated or differentiated regulation of plant functional traits.Plant resource acquisition involves root trait plasticity and mycorrhizal symbiosis.However,root trait plasticity along precipitation gradients and root-mycorrhizal trade-offs remain unclear.We conducted community surveys along a west-east precipitation gradient in four natural grassland communities(alpine desert steppe,alpine steppe,alpine meadow steppe and alpine meadow)on the plateau in northern Xizang Plateau.Six key root traits(root diameter,RD;root dry matter content,RDMC;root tissue density,RTD;specific root length,SRL;root branching intensity,RBI;and root length colonization percentage,RLC)were measured in 18 alpine plant species to investigate the coordination and trade-offs between root traits and mycorrhizal fungi along the precipitation gradient.Our results showed community-level declines in RDMC,RD,RTD and RLC with increasing precipitation,contrasting with elevated RBI and SRL.Functional groups exhibited distinct patterns:grasses and legumes demonstrated root-mycorrhizal trade-offs,sedges displayed synergy and forbs showed inconsistent responses.Divergent trends in plant root traits and mycorrhizal fungi were observed at the species level.Alpine plants in humid eastern meadows favored root elongation,while those in arid western desert steppe relied on radial growth and mycorrhizal fungal cooperation for resource acquisition.These findings highlight varied root absorption strategies among alpine plants along environmental gradients,supporting the importance of ecological niche diversification in maintaining alpine ecosystem diversity and stability.
基金supported by the National Natural Science Foundation of China(Grant No.U1803231).
文摘How sex-related root traits and soil microbes and their interactions respond to drought remains unclear.Here,we investigated how fine root traits and the composition of rhizosphere microbial communities in Populus euphratica females and males respond to drought in concert in 17-year-old plantations.Females increased specific root length(SRL)in response to drought.However,males showed no changes in their roots but significant increases in arbuscular mycorrhizal hyphal biomass and population of Gram-negative bacteria in the rhizosphere.Also,fungal symbiotroph communities associated with root systems in males differed from those in females under drought.We further demonstrated that the Gram-positive to Gram-negative bacteria ratios positively correlated with the SRL,while fungi to bacteria ratios were negatively correlated.Meanwhile,the relative abundance of symbiotrophs was negatively correlated with the SRL,while saprotroph abundance was positively correlated.Nevertheless,the relative abundance of symbiotrophs was positively correlated with the root carbon content(RCC).These findings indicate that microbial responses to drought depend highly upon the sex of the plant and microbial group and are related to root trait adjustments to drought.This discovery also highlights the role of plant-microbial interactions in the ecosystems of P.euphratica forest plantations.
基金French Research National Agency(O2LA project ANR-09-STRA-09).
文摘Aims root systems play an essential role in grassland functioning in both acquisition and storage of resources.Nevertheless,root functional traits have not received as much attention as those measured on above-ground organs,and little is known about their relations.our objec-tives were to test whether morphological and root system traits allowed identification of grass species’functional strategies and to determine whether a relation exists between above-and below-ground traits.Methods Functional traits of root tissues(specific root length,diameter,tissue density and nitrogen concentration),whole root systems(root mass,root length density,root mass percentage below a depth of 20 cm and fine root%)and two major leaf traits(specific leaf area and leaf dry matter content)were determined under field conditions and their rela-tions were analysed in eleven perennial temperate Poaceae species.Important Findings Canonical correspondence analysis along axis 1 revealed a gra-dient of species,from those with deep,dense and coarse root systems with a large root mass to those with shallow root sys-tems,thin roots and high specific root length;this suggests strong correlations among root traits.Correlations between specific root length and specific leaf area reveal two groups of species,which probably indicates different drought-tolerance capacities.root trait syndromes enable ranking grasses along a gradient from conservative-strategy species(from stressful habitats),which display a deep and coarse root system,to acquisitive species(from rich and moist meadows),which display a shallow and thin root system.although both types display similar above-ground strategies,drought-tolerant species have lower specific root lengths than drought-sensitive species,revealing more conservative root strategies.
基金funded by Sichuan Science and Technology Program(2023NSFSC0195).
文摘Background Changes in precipitation alter soil moisture,thereby afecting the aboveground and belowground ecological processes.However,it remains unclear whether plant root systems alter these efects through rhizospheric processes.In this study,a precipitation control experiment was conducted in the alpine grassland of northern Xizang to simulate precipitation changes with a 50%decrease and 50%increase in precipitation.Nutrient and microbial biomass,root traits,and survival strategies in the rhizosphere and bulk soils of the dominant plant,Stipa purpurea,were analyzed for alterations under precipitation changes.Results Increased precipitation(IP)signifcantly decreased the rhizosphere soil total phosphorus and bulk soil ammonium nitrogen and increased the rhizosphere soil total potassium.Decreasing precipitation(DP)signifcantly increased the rhizosphere soil total potassium and decreased the bulk soil total potassium.DP signifcantly reduced microbial biomass carbon,nitrogen and phosphorus in rhizosphere soil,while IP signifcantly increased the bulk soil MBC:MBP,soil C:P imbalance,and soil N:P imbalance.Along the PC1 axis,where the contribution of the traits was relatively large,it was possible to defne the root economic spectrum.The root system of Stipa purpurea from the DP treatment was distributed on the conservative side of the economic spectrum,whereas that from the control and IP treatments were clustered on the acquisition side.Conclusions Increasing and decreasing precipitation mainly afected the contents of total phosphorus and total potassium in rhizosphere soil and the contents of ammonium nitrogen and total potassium in bulk soil of Stipa purpurea.The microbial biomass carbon,nitrogen and phosphorus were mainly afected by a decrease in precipitation.Decreasing precipitation signifcantly reduced microbial biomass carbon,nitrogen and phosphorus,but the rhizosphere MBC:MBN,MBC:MBP and MBN:MBP remained stable under the change of precipitation.Increasing precipitation exacerbated the C:P imbalance and N:P imbalance in bulk soil,and increased the demand for phosphorus by bulk microorganisms.Increased precipitation promoted root access to resources.The root system of Stipa purpurea in the context of precipitation changes was driven by rhizosphere nutrients and bulk microorganisms.This study is important for revealing plant–microbe–soil interactions in terrestrial ecosystems.
