In rice-wheat rotation systems, changes in soil phosphorus(P) pools and microorganisms in rice-growing seasons have been studied;however, further investigations are required to test whether these indexes exhibit diffe...In rice-wheat rotation systems, changes in soil phosphorus(P) pools and microorganisms in rice-growing seasons have been studied;however, further investigations are required to test whether these indexes exhibit different responses in wheat-growing seasons. Additionally, such studies need to include potential variations in soil carbon(C) structure and microbial community composition. In this study, a long-term rice-wheat rotation P-input reduction experiment was conducted to observe the variations in soil P pools and C composition in the 7th wheat season and to investigate the responses of soil enzyme activity and microbial communities. Four P fertilization treatments were included in the experiment, i.e., P application for rice season only(PR), for wheat season only(PW), and for both rice and wheat seasons(PR+W) and no P application in either season(Pzero). Compared with PR+W treatment, Pzero treatment significantly decreased(P < 0.05) labile and stable P pools. Different P fertilization regimes altered soil microbial community composition and enzyme activity, whereas C composition did not vary. However, PW treatment resulted in relatively more O-alkyl-C than PR treatment and the highest number of microorganisms. Besides, the higher ratios of fungi/bacteria and Gram-positive bactetia/Gram-negative bactetia were related to labile C pools, particularly O-alkyl-C, as opposed to recalcitrant C. Our results clarified the status of soil P pools, C chemistry, and the response of microorganisms under dry-farming conditions in the P input-reduced rice-wheat rotation system.展开更多
Stoichiometry plays a crucial role in biogeochemical cycles and can modulate soil nutrient availability and functions. In agricultural ecosystems,phosphorus(P) fertilizers(organic or chemical) are often applied to ach...Stoichiometry plays a crucial role in biogeochemical cycles and can modulate soil nutrient availability and functions. In agricultural ecosystems,phosphorus(P) fertilizers(organic or chemical) are often applied to achieve high crop yields. However, P is readily fixed by soil particles, leading to low P use efficiency. Therefore, understanding the role of carbon:nitrogen:P stoichiometries of soil and microorganisms in soil P transformation is of great significance for P management in agriculture. This paper provides a comprehensive review of the recent research on stoichiometry effect on soil P transformation in agricultural ecosystems. Soil microorganisms play an important role in the transformation of soil non-labile inorganic P to microbial biomass P by regulating microbial biomass stoichiometry. They also mobilize soil unavailable organic P into available P by changing ecoenzyme stoichiometry. Organic materials, such as manure and straw, play an important role in promoting the transformation of insoluble P into available P as well. Additionally, periphytic biofilms can reduce P loss from rice field ecosystems. Agricultural stoichiometries are different from those of natural ecosystems and thereby should receive more attention due to the influences of anthropogenic factors. Therefore, it is necessary to conduct further stoichiometry research on the soil biochemical mechanisms underlying P transformation in agricultural ecosystems. In conclusion, understanding stoichiometry impact on soil P transformation is crucial for P management in agricultural ecosystems.展开更多
In agricultural systems, it is vital to use limited yet optimal phosphorus(P) resources, because excessive P fertilizer application leads to the accumulation of P in soil, increasing the risk of environmental pollutio...In agricultural systems, it is vital to use limited yet optimal phosphorus(P) resources, because excessive P fertilizer application leads to the accumulation of P in soil, increasing the risk of environmental pollution and causing the waste and exhaustion of P resources. In a rice-wheat rotation system, omitting P fertilizer application in the rice-growing season is a good alternative;however, how this P fertilization reduction influences changes in P in the soil-root-aboveground system is unclear. In this study, after a seven-year rice-wheat rotation at the Yixing(YX) and Changshu(CS) sampling sites, China, compared with P fertilization in rice-and wheat-growing seasons(PR+W), reduced P fertilization(no P fertilizer application in either season, P0;P fertilization only in wheat-growing seasons, PW;and P fertilization only in rice-growing seasons, PR) did not result in substantial variation in crop biomass. The PW treatment did not reduce crop total P, root iron(Fe)-plaque P, and soil Olsen-P at three stages of rice growth(seedling, booting, and harvesting stages) at the YX and CS sites. In contrast, concentrations of soil Olsen-P, aboveground crop total P, and root Fe-plaque P decreased in the P0 treatment by 45.8%–81.0%,24.6%–30.9%, and 45.6%–73.4%, respectively. In addition, a significant negative correlation was observed between the root Fe-plaque P and crop biomass at the two sites. Significant positive correlations were also observed between root Fe-plaque P and root total P, crop total P, and soil Olsen-P. In addition, the results of a redundancy analysis revealed that soil alkaline phosphatase(ALP) played a major role in the supply of P in soil, and was closely associated with root Fe-plaque P. The results of this study will enhance the understanding of the changes in P in the soil-root-aboveground system, particularly under P fertilizer reduction regimes.展开更多
The altered lysosomal function can induce drug redistribution which leads to drug resistance and poor prognosis for cancer patients.V-ATPase,an ATP-driven proton pump positioned at lysosomal surfaces,is responsible fo...The altered lysosomal function can induce drug redistribution which leads to drug resistance and poor prognosis for cancer patients.V-ATPase,an ATP-driven proton pump positioned at lysosomal surfaces,is responsible for maintaining the stability of lysosome.Herein,we reported that the potassium voltage-gated channel subfamily J member 15(KCNJ15)protein,which may bind to V-ATPase,can regulate the function of lysosome.The deficiency of KCNJ15 protein in breast cancer cells led to drug aggregation as well as reduction of drug efficacy.The application of the V-ATPase inhibitor could inhibit the binding between KCNJ15 and V-ATPase,contributing to the amelioration of drug resistance.Clinical data analysis revealed that KCNJ15 deficiency was associated with higher histological grading,advanced stages,more metastases of lymph nodes,and shorter disease free survival of patients with breast cancer.KCNJ15 expression level is positively correlated with a high response rate after receiving neoadjuvant chemotherapy.Moreover,we revealed that the small molecule drug CMA/BAF can reverse drug resistance by disrupting the interaction between KCNJ15 and lysosomes.In conclusion,KCNJ15 could be identified as an underlying indicator for drug resistance and survival of breast cancer,which might guide the choice of therapeutic strategies.展开更多
Significant heterogeneity exists in hormone receptor(HR)-positive/HER2-positive(HR+/HER2+)breast cancer,contributing to suboptimal pathological complete response rates with conventional neoadjuvant treatment regimens....Significant heterogeneity exists in hormone receptor(HR)-positive/HER2-positive(HR+/HER2+)breast cancer,contributing to suboptimal pathological complete response rates with conventional neoadjuvant treatment regimens.Overcoming this challenge requires precise molecular classification,which is pivotal for the development of targeted therapies.We conducted molecular typing on a cohort of 211 patients with HR^(+)/HER2^(+) breast cancer and performed a comprehensive analysis of the efficacy of various neoadjuvant treatment regimens.Our findings revealed four distinct molecular subtypes,each exhibiting unique characteristics and therapeutic implications.The HER2-enriched subtype,marked by activation of the HER2 signaling and hypoxiainducible factor 1(HIF-1)pathway,may benefit from intensified anti-HER2-targeted therapy.Estrogen receptor(ER)-activated subtype demonstrated potential sensitivity to combined therapeutic strategies targeting both ER and HER2 pathways.Characterized by high immune cell infiltration,the immunomodulatory subtype showed sensitivity to HER2-targeted antibody-drug conjugates(ADCs)and promise for immune checkpoint therapy.The highly heterogeneous subtype requires a multifaceted therapeutic approach.Organoid susceptibility assays suggested phosphoinositide 3-kinase inhibitors may be a potential treatment option.These findings underscore the importance of molecular subtyping in HR^(+)/HER2^(+) breast cancer,offering a framework for developing precise and personalized treatment strategies.By addressing the heterogeneity of the disease,these approaches have the potential to optimize therapeutic outcomes and improve patient care.展开更多
Erratum to:SCIENCE CHINA Life Sciences,Volume 66,Issue 12:2805-2817(2023),https://doi.org/10.1007/s11427-023-2343-y.This paper contains errors in Figure 1B and Figure 5A,where the representative images of immunohistoc...Erratum to:SCIENCE CHINA Life Sciences,Volume 66,Issue 12:2805-2817(2023),https://doi.org/10.1007/s11427-023-2343-y.This paper contains errors in Figure 1B and Figure 5A,where the representative images of immunohistochemical staining of FSIP1 in TNBC tissues and Western blot band of Nanog in 231-WT and 231-F KO cells were misused.展开更多
CDK4/6 inhibitors are routinely recommended agents for the treatment of advanced HR+HER2-breast cancer.However,their therapeutic effectiveness in triple-negative breast cancer(TNBC)remains controversial.Here,we observ...CDK4/6 inhibitors are routinely recommended agents for the treatment of advanced HR+HER2-breast cancer.However,their therapeutic effectiveness in triple-negative breast cancer(TNBC)remains controversial.Here,we observed that the expression level of fibrous sheath interacting protein 1(FSIP1)could predict the treatment response of TNBC to CDK4/6 inhibitors.High FSIP1 expression level was related to a poor prognosis in TNBC,which was associated with the ability of FSIP1 to promote tumor cell proliferation.FSIP1 downregulation led to slowed tumor growth and reduced lung metastasis in TNBC.FSIP1knockout caused cell cycle arrest at the G0/G1 phase and reduced treatment sensitivity to CDK4/6 inhibitors by inactivating the Nanog/CCND1/CDK4/6 pathway.FSIP1 could form a complex with Nanog,protecting it from ubiquitination and degradation,which may facilitate the rapid cell cycle transition from G0/G1 to S phase and exhibit enhanced sensitivity to CDK4/6 inhibitors.Our findings suggest that TNBC patients with high FSIP1 expression levels may be suitable candidates for CDK4/6 inhibitor treatment.展开更多
Little attention has been paid to how long-term application of crop straw and its biochar affects soil phosphorus(P)transformation and carbon(C)fractions.We conducted a 7-year field experiment including control treatm...Little attention has been paid to how long-term application of crop straw and its biochar affects soil phosphorus(P)transformation and carbon(C)fractions.We conducted a 7-year field experiment including control treatment(chemical fertilizer only,CK),straw return(2.25 t ha^(−1)),and different amounts of biochar addition(11.25 t ha^(−1)(0.5%BC)and 22.5 t ha^(−1)(1.0%BC),to investigate influence of these amendments on soil C structure,P fractions,and their interaction with microorganisms.The 13C nuclear magnetic resonance and soil P sequence fractionation were applied to capture changes of soil C compositions and P pool.Compared to CK,straw and biochar amendments decreased alkyl C/O-alkyl C,which is conducive to increased soil organic C.The 0.5%BC and 1.0%BC treatments enhanced recalcitrant aromatic C by 69.0%and 131%,respectively.Compared to CK(101.2±33.32 mg kg^(−1)),the 0.5%BC and 1.0%BC treatments had a negligible effect on soil available P,while negative effects were observed in straw treatment(59.79±9.023 mg kg^(−1)).Straw and biochar amendments increased primary P and occluded P,whereas had negligible effect on organic P.Redundancy analysis and correlation analysis indi-cated that C compositions and P pool correlated to microbial community composition and enzyme activities,and aromatic C was the most related factor.Moreover,structural equation modeling indicated available P was most related to phosphatase activity and C composition.Our findings reveal the changes of soil P and C response under long-term crop straw and its biochar amendment,and can contribute toward improving understanding of the effect of biochar and straw return in future agriculture management.展开更多
Phosphorus(P)availability,diffusion,and resupply processes can be altered by biochar addition in flooded rice rhizosphere,which controls the risk of P release to the environment.However,there are few in-situ investiga...Phosphorus(P)availability,diffusion,and resupply processes can be altered by biochar addition in flooded rice rhizosphere,which controls the risk of P release to the environment.However,there are few in-situ investigations of these rhizospheric processes and effects.To explore the effects of biochar addition on soil P availability,high-resolution dialysis(HR-Peeper),diffusive gradients in thin films(DGT),and zymography techniques were used to provide direct evidence in the rice rhizosphere at the sub-millimeter scale.Long-term(9-years)field and greenhouse pot experiments demonstrated that biochar addition notably decreased the soluble/labile P and Fe concentrations in rice rhizosphere(vs.no biochar addition;CK)based on the results of Peeper,DGT,and two-dimensional imaging of labile P fluxes.DGT-induced fluxes in the soil/sediment(DIFS)model and sediment P release risk index(SPRRI)further indicated that biochar addition decreased the diffusion and resupply capacity of P from soil solid to the solution,thereby decreasing P release risk to the environment.These processes were dominated by Fe redox cycling and the hydrolysis of Al(hydro)oxides that greatly increased the unavailable P(Ca-P and residual-P).Additionally,greenhouse pot experiments(without additional biochar)showed that the previous long-term biochar addition significantly increased soil phosphatase activity,due to an adaptive-enhancing response to P decrease in the rhizosphere zone.The in-situ study on the biogeochemical reactions of P in the rice rhizosphere may provide a new and direct perspective to better evaluate the biochar addition and potential benefits to agricultural soils.展开更多
基金funded by the National Natural Science Foundation of China (No. 41671304)the National Key Research and Development Program of China (No. 2017YFD0200206)。
文摘In rice-wheat rotation systems, changes in soil phosphorus(P) pools and microorganisms in rice-growing seasons have been studied;however, further investigations are required to test whether these indexes exhibit different responses in wheat-growing seasons. Additionally, such studies need to include potential variations in soil carbon(C) structure and microbial community composition. In this study, a long-term rice-wheat rotation P-input reduction experiment was conducted to observe the variations in soil P pools and C composition in the 7th wheat season and to investigate the responses of soil enzyme activity and microbial communities. Four P fertilization treatments were included in the experiment, i.e., P application for rice season only(PR), for wheat season only(PW), and for both rice and wheat seasons(PR+W) and no P application in either season(Pzero). Compared with PR+W treatment, Pzero treatment significantly decreased(P < 0.05) labile and stable P pools. Different P fertilization regimes altered soil microbial community composition and enzyme activity, whereas C composition did not vary. However, PW treatment resulted in relatively more O-alkyl-C than PR treatment and the highest number of microorganisms. Besides, the higher ratios of fungi/bacteria and Gram-positive bactetia/Gram-negative bactetia were related to labile C pools, particularly O-alkyl-C, as opposed to recalcitrant C. Our results clarified the status of soil P pools, C chemistry, and the response of microorganisms under dry-farming conditions in the P input-reduced rice-wheat rotation system.
基金financial support from the Natural Science Foundation of Jiangsu Province,China(No.BK20230049)the National Natural Science Foundation of China(No.42277026)+2 种基金the 14th Five-Year Plan Innovation Program of the Institute of Soil Science,Chinese Academy of Sciences(No.ISSASIP2201)the Major Science and Technology of Inner Mongolia Autonomous Region,China(No.NMKJXM202009)the Program for Excellent Postdoctoral Talents of Jiangsu,China(No.2022ZB533)。
文摘Stoichiometry plays a crucial role in biogeochemical cycles and can modulate soil nutrient availability and functions. In agricultural ecosystems,phosphorus(P) fertilizers(organic or chemical) are often applied to achieve high crop yields. However, P is readily fixed by soil particles, leading to low P use efficiency. Therefore, understanding the role of carbon:nitrogen:P stoichiometries of soil and microorganisms in soil P transformation is of great significance for P management in agriculture. This paper provides a comprehensive review of the recent research on stoichiometry effect on soil P transformation in agricultural ecosystems. Soil microorganisms play an important role in the transformation of soil non-labile inorganic P to microbial biomass P by regulating microbial biomass stoichiometry. They also mobilize soil unavailable organic P into available P by changing ecoenzyme stoichiometry. Organic materials, such as manure and straw, play an important role in promoting the transformation of insoluble P into available P as well. Additionally, periphytic biofilms can reduce P loss from rice field ecosystems. Agricultural stoichiometries are different from those of natural ecosystems and thereby should receive more attention due to the influences of anthropogenic factors. Therefore, it is necessary to conduct further stoichiometry research on the soil biochemical mechanisms underlying P transformation in agricultural ecosystems. In conclusion, understanding stoichiometry impact on soil P transformation is crucial for P management in agricultural ecosystems.
基金funded by The National Key Research and Development Program of China (No. 2017YFD0800103)the National Natural Science Foundation of China (No. 41671304)the Key Projects in the National “948” Program during the Twelfth Five-Year Plan Period (No. 2011-G30)。
文摘In agricultural systems, it is vital to use limited yet optimal phosphorus(P) resources, because excessive P fertilizer application leads to the accumulation of P in soil, increasing the risk of environmental pollution and causing the waste and exhaustion of P resources. In a rice-wheat rotation system, omitting P fertilizer application in the rice-growing season is a good alternative;however, how this P fertilization reduction influences changes in P in the soil-root-aboveground system is unclear. In this study, after a seven-year rice-wheat rotation at the Yixing(YX) and Changshu(CS) sampling sites, China, compared with P fertilization in rice-and wheat-growing seasons(PR+W), reduced P fertilization(no P fertilizer application in either season, P0;P fertilization only in wheat-growing seasons, PW;and P fertilization only in rice-growing seasons, PR) did not result in substantial variation in crop biomass. The PW treatment did not reduce crop total P, root iron(Fe)-plaque P, and soil Olsen-P at three stages of rice growth(seedling, booting, and harvesting stages) at the YX and CS sites. In contrast, concentrations of soil Olsen-P, aboveground crop total P, and root Fe-plaque P decreased in the P0 treatment by 45.8%–81.0%,24.6%–30.9%, and 45.6%–73.4%, respectively. In addition, a significant negative correlation was observed between the root Fe-plaque P and crop biomass at the two sites. Significant positive correlations were also observed between root Fe-plaque P and root total P, crop total P, and soil Olsen-P. In addition, the results of a redundancy analysis revealed that soil alkaline phosphatase(ALP) played a major role in the supply of P in soil, and was closely associated with root Fe-plaque P. The results of this study will enhance the understanding of the changes in P in the soil-root-aboveground system, particularly under P fertilizer reduction regimes.
基金supported by the National Natural Science Foundation of China(#81872159,#81902607,and#81874301)the Liaoning Colleges Innovative Talent Support Program(#Cancer Stem Cell Origin and Biology Behavior)+2 种基金the Major Project Construction Foundation of China Medical University(#2017ZDZX05)the Outstanding Scientific Fund of Shengjing Hospital(#201803)the Outstanding Young Scholars of Liaoning Province(#2019-YQ-10).
文摘The altered lysosomal function can induce drug redistribution which leads to drug resistance and poor prognosis for cancer patients.V-ATPase,an ATP-driven proton pump positioned at lysosomal surfaces,is responsible for maintaining the stability of lysosome.Herein,we reported that the potassium voltage-gated channel subfamily J member 15(KCNJ15)protein,which may bind to V-ATPase,can regulate the function of lysosome.The deficiency of KCNJ15 protein in breast cancer cells led to drug aggregation as well as reduction of drug efficacy.The application of the V-ATPase inhibitor could inhibit the binding between KCNJ15 and V-ATPase,contributing to the amelioration of drug resistance.Clinical data analysis revealed that KCNJ15 deficiency was associated with higher histological grading,advanced stages,more metastases of lymph nodes,and shorter disease free survival of patients with breast cancer.KCNJ15 expression level is positively correlated with a high response rate after receiving neoadjuvant chemotherapy.Moreover,we revealed that the small molecule drug CMA/BAF can reverse drug resistance by disrupting the interaction between KCNJ15 and lysosomes.In conclusion,KCNJ15 could be identified as an underlying indicator for drug resistance and survival of breast cancer,which might guide the choice of therapeutic strategies.
基金supported by the National Natural ScienceFoundation of China(Grant Nos.U20A20381,82203804,82403918)the National Natural ScienceFoundation of Liaoning Province(Grant No.2024-MS-053)China Medical Education Association Subject(2016001).
文摘Significant heterogeneity exists in hormone receptor(HR)-positive/HER2-positive(HR+/HER2+)breast cancer,contributing to suboptimal pathological complete response rates with conventional neoadjuvant treatment regimens.Overcoming this challenge requires precise molecular classification,which is pivotal for the development of targeted therapies.We conducted molecular typing on a cohort of 211 patients with HR^(+)/HER2^(+) breast cancer and performed a comprehensive analysis of the efficacy of various neoadjuvant treatment regimens.Our findings revealed four distinct molecular subtypes,each exhibiting unique characteristics and therapeutic implications.The HER2-enriched subtype,marked by activation of the HER2 signaling and hypoxiainducible factor 1(HIF-1)pathway,may benefit from intensified anti-HER2-targeted therapy.Estrogen receptor(ER)-activated subtype demonstrated potential sensitivity to combined therapeutic strategies targeting both ER and HER2 pathways.Characterized by high immune cell infiltration,the immunomodulatory subtype showed sensitivity to HER2-targeted antibody-drug conjugates(ADCs)and promise for immune checkpoint therapy.The highly heterogeneous subtype requires a multifaceted therapeutic approach.Organoid susceptibility assays suggested phosphoinositide 3-kinase inhibitors may be a potential treatment option.These findings underscore the importance of molecular subtyping in HR^(+)/HER2^(+) breast cancer,offering a framework for developing precise and personalized treatment strategies.By addressing the heterogeneity of the disease,these approaches have the potential to optimize therapeutic outcomes and improve patient care.
文摘Erratum to:SCIENCE CHINA Life Sciences,Volume 66,Issue 12:2805-2817(2023),https://doi.org/10.1007/s11427-023-2343-y.This paper contains errors in Figure 1B and Figure 5A,where the representative images of immunohistochemical staining of FSIP1 in TNBC tissues and Western blot band of Nanog in 231-WT and 231-F KO cells were misused.
基金supported by the National Natural Science Foundation of China (82203804,81872159)345 Talent Project of Shengjing Hospital of China Medical University。
文摘CDK4/6 inhibitors are routinely recommended agents for the treatment of advanced HR+HER2-breast cancer.However,their therapeutic effectiveness in triple-negative breast cancer(TNBC)remains controversial.Here,we observed that the expression level of fibrous sheath interacting protein 1(FSIP1)could predict the treatment response of TNBC to CDK4/6 inhibitors.High FSIP1 expression level was related to a poor prognosis in TNBC,which was associated with the ability of FSIP1 to promote tumor cell proliferation.FSIP1 downregulation led to slowed tumor growth and reduced lung metastasis in TNBC.FSIP1knockout caused cell cycle arrest at the G0/G1 phase and reduced treatment sensitivity to CDK4/6 inhibitors by inactivating the Nanog/CCND1/CDK4/6 pathway.FSIP1 could form a complex with Nanog,protecting it from ubiquitination and degradation,which may facilitate the rapid cell cycle transition from G0/G1 to S phase and exhibit enhanced sensitivity to CDK4/6 inhibitors.Our findings suggest that TNBC patients with high FSIP1 expression levels may be suitable candidates for CDK4/6 inhibitor treatment.
基金Jiangsu Agriculture Science and Technology Innovation Fund(CX(19)1007)the National Natural Science Foundation of China(No.41671304).
文摘Little attention has been paid to how long-term application of crop straw and its biochar affects soil phosphorus(P)transformation and carbon(C)fractions.We conducted a 7-year field experiment including control treatment(chemical fertilizer only,CK),straw return(2.25 t ha^(−1)),and different amounts of biochar addition(11.25 t ha^(−1)(0.5%BC)and 22.5 t ha^(−1)(1.0%BC),to investigate influence of these amendments on soil C structure,P fractions,and their interaction with microorganisms.The 13C nuclear magnetic resonance and soil P sequence fractionation were applied to capture changes of soil C compositions and P pool.Compared to CK,straw and biochar amendments decreased alkyl C/O-alkyl C,which is conducive to increased soil organic C.The 0.5%BC and 1.0%BC treatments enhanced recalcitrant aromatic C by 69.0%and 131%,respectively.Compared to CK(101.2±33.32 mg kg^(−1)),the 0.5%BC and 1.0%BC treatments had a negligible effect on soil available P,while negative effects were observed in straw treatment(59.79±9.023 mg kg^(−1)).Straw and biochar amendments increased primary P and occluded P,whereas had negligible effect on organic P.Redundancy analysis and correlation analysis indi-cated that C compositions and P pool correlated to microbial community composition and enzyme activities,and aromatic C was the most related factor.Moreover,structural equation modeling indicated available P was most related to phosphatase activity and C composition.Our findings reveal the changes of soil P and C response under long-term crop straw and its biochar amendment,and can contribute toward improving understanding of the effect of biochar and straw return in future agriculture management.
基金the National Natural Science Foundation of China(No.42277026)the National Key Research and Development Program of China(2021YFD1700802)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA28090300).
文摘Phosphorus(P)availability,diffusion,and resupply processes can be altered by biochar addition in flooded rice rhizosphere,which controls the risk of P release to the environment.However,there are few in-situ investigations of these rhizospheric processes and effects.To explore the effects of biochar addition on soil P availability,high-resolution dialysis(HR-Peeper),diffusive gradients in thin films(DGT),and zymography techniques were used to provide direct evidence in the rice rhizosphere at the sub-millimeter scale.Long-term(9-years)field and greenhouse pot experiments demonstrated that biochar addition notably decreased the soluble/labile P and Fe concentrations in rice rhizosphere(vs.no biochar addition;CK)based on the results of Peeper,DGT,and two-dimensional imaging of labile P fluxes.DGT-induced fluxes in the soil/sediment(DIFS)model and sediment P release risk index(SPRRI)further indicated that biochar addition decreased the diffusion and resupply capacity of P from soil solid to the solution,thereby decreasing P release risk to the environment.These processes were dominated by Fe redox cycling and the hydrolysis of Al(hydro)oxides that greatly increased the unavailable P(Ca-P and residual-P).Additionally,greenhouse pot experiments(without additional biochar)showed that the previous long-term biochar addition significantly increased soil phosphatase activity,due to an adaptive-enhancing response to P decrease in the rhizosphere zone.The in-situ study on the biogeochemical reactions of P in the rice rhizosphere may provide a new and direct perspective to better evaluate the biochar addition and potential benefits to agricultural soils.
