BACKGROUND Liver transplantation aims to increase the survival of patients with end-stage liver diseases and improve their quality of life.The number of organs available for transplantation is lower than the demand.To...BACKGROUND Liver transplantation aims to increase the survival of patients with end-stage liver diseases and improve their quality of life.The number of organs available for transplantation is lower than the demand.To provide fair organ distribution,predictive mortality scores have been developed.AIM To compare the Acute Physiology and Chronic Health Evaluation IV(APACHE IV),balance of risk(BAR),and model for end-stage liver disease(MELD)scores as predictors of mortality.METHODS Retrospective cohort study,which included 283 adult patients in the postoperative period of deceased donor liver transplantation from 2014 to 2018.RESULTS The transplant recipients were mainly male,with a mean age of 58.1 years.Donors were mostly male,with a mean age of 41.6 years.The median cold ischemia time was 3.1 hours,and the median intensive care unit stay was 5 days.For APACHE IV,a mean of 59.6 was found,BAR 10.7,and MELD 24.2.The 28-day mortality rate was 9.5%,and at 90 days,it was 3.5%.The 28-day mortality prediction for APACHE IV was very good[area under the curve(AUC):0.85,P<0.001,95%CI:0.76-0.94],P<0.001,BAR(AUC:0.70,P<0.001,95%CI:0.58–0.81),and MELD(AUC:0.66,P<0.006,95%CI:0.55-0.78),P<0.008.At 90 days,the data for APACHE IV were very good(AUC:0.80,P<0.001,95%CI:0.71–0.90)and moderate for BAR and MELD,respectively,(AUC:0.66,P<0.004,95%CI:0.55–0.77),(AUC:0.62,P<0.026,95%CI:0.51–0.72).All showed good discrimination between deaths and survivors.As for the best value for liver transplantation,it was significant only for APACHE IV(P<0.001).CONCLUSION The APACHE IV assessment score was more accurate than BAR and MELD in predicting mortality in deceased donor liver transplant recipients.展开更多
Hypnosis is a promising tool in the management of various conditions,such as anxiety and chronic pain.Preliminary studies have shown that hypnosis can directly affect the cardiovascular system,as it increases parasymp...Hypnosis is a promising tool in the management of various conditions,such as anxiety and chronic pain.Preliminary studies have shown that hypnosis can directly affect the cardiovascular system,as it increases parasympathetic activation and reduces sympathetic activity.However,the literature related to the effects of hypnosis on cardiovascular health is scarce,mainly due to misconceptions about hypnosis among researchers and medical professionals.This opinion paper examines the role that hypnosis may play in cardiovascular health,highlighting the physiological mechanisms behind it.The evidence suggests that hypnosis has both direct(e.g.,changes in the activity of the autonomic nervous system)and indirect(e.g.,changes in healthy behaviours)effects on the cardiovascular system;however,further studies are needed to properly define its mechanisms of action and its applicability in improving cardiovascular health.Thus,this opinion paper advocates the adoption of the term“hypno-cardiac physiology”to identify a new research area that gathers experts from neuroscience and cardiovascular science with the joint aim of seeking further understanding of the effects of hypnosis on the cardiovascular system.The adoption of a dedicated term to identify the study of the cardiovascular response to hypnosis will encourage its implementation in cardiovascular health interventions,promoting awareness of its effects among the public and the healthcare community,and promoting the formation of dedicated multidisciplinary research groups and dedicated educational training for healthcare professional interested in its applications.展开更多
BACKGROUND Previous studies have reported the high predictive accuracy of 4C Mortality Score derived at hospital admission in coronavirus disease 2019(COVID-19)patients.Very few studies have assessed it at intensive c...BACKGROUND Previous studies have reported the high predictive accuracy of 4C Mortality Score derived at hospital admission in coronavirus disease 2019(COVID-19)patients.Very few studies have assessed it at intensive care unit(ICU)admission and compared it with the Acute Physiology and Chronic Health Evaluation(APACHE)II score.There are no studies comparing its accuracy with APACHE III score.AIM To describe the characteristics and outcomes of patients admitted to ICU with COVID-19 infection and to compare the accuracy of 4C score and APACHE score in predicting mortality in these patients.METHODS We conducted this retrospective cohort study using an electronic database in a tertiary ICU in Sydney.We included all adult patients(age>16 years)admitted to ICU with COVID-19 infection over a 5-month period(July 1,2021 to November 30,2021).We collected the data on demographics,clinical characteristics,interventions and outcomes for all patients.We calculated the 4C Mortality Score for each patient using eight variables as described previously.We compared the predictive accuracy of 4C Mortality Score at hospital and ICU admission and APACHE II and III scores by area under the receiver operating characteristic curve(AUROC).We determined the optimal cut-off value for each of these scores using the‘nearest’method and its 95%confidence interval by bootstrapping.RESULTS A total of 140 patients(62%males,mean age 56±17 years,mean APACHE II score 13±57)were included in the study.Nineteen(13.6%)of 140 patients died in the hospital.Compared to survivors,the non-survivors were older,males,had more comorbidities,higher rate of mechanical ventilation and vasopressor use.The AUROC for the 4C Mortality Score at hospital and ICU admission and APACHE II and II score was 0.75,0.80.0.75 and 0.79 respectively.The optimal cut-off value for these four scores was 9,10,14 and 56 respectively.The cut-point for all the scores had higher sensitivity than specificity.CONCLUSION The 4C score at ICU admission had a higher accuracy in predicting mortality than the 4C score at hospital admission.The predictive accuracy was similar to that for APACHE III score.The 4C score at ICU admission needs to be validated in future studies.展开更多
Publisher Correction to:Journal of Forestry Research(2025)36:29 https://doi.org/10.1007/s11676-025-01823-0 In Fig.4c of this article,the lower part of the figure was unintentionally cropped and incomplete during the p...Publisher Correction to:Journal of Forestry Research(2025)36:29 https://doi.org/10.1007/s11676-025-01823-0 In Fig.4c of this article,the lower part of the figure was unintentionally cropped and incomplete during the publisher's production process.The published incorrect version and the corrected version of Fig.4 are given below.展开更多
Vegetation annual gross primary production(AGPP),the total yearly carbon assimilation via photosynthesis,serves as a key indicator of ecosystem carbon uptake.While AGPP variations are jointly influenced by both vegeta...Vegetation annual gross primary production(AGPP),the total yearly carbon assimilation via photosynthesis,serves as a key indicator of ecosystem carbon uptake.While AGPP variations are jointly influenced by both vegetation phenology and physiology,the effectiveness of satellite-derived indicators in capturing these variations has not been fully evaluated.This study develops and evaluates the satellite-derived phenology and physiology indicators for modeling AGPP variability.We assessed the performance of satellite-derived metrics,including solar-induced chlorophyll fluorescence(SIF),leaf area index(LAI),and enhanced vegetation index(EVI),in capturing AGPP variations.Among these,SIF-based indicators exhibited the highest accuracy(Pearson's r=0.79;root mean square error=414.7 gC·m^(-2)·year^(-1)),outperforming LAI-and EVI-based indicators.To further investigate the mechanisms driving AGPP variability,we used a structural equation model based on in situ observations to quantify the direct and indirect effects of climate on AGPP through phenology and physiology.Our results reveal that vegetation physiology,particularly the seasonal maximum gross primary production,plays a more dominant role in regulating AGPP than phenology.Furthermore,we found that globally,SIF-derived phenology indicators tend to be lower than those from LAI and EVI,whereas SIF-derived physiology indicators are elevated in tropical regions and the Southern Hemisphere.These findings highlight the potential of satellite-derived indicators in advancing AGPP modeling and emphasize the predominant role of vegetation physiology in regulating ecosystem carbon uptake.This study contributes to a refined understanding of global carbon cycle dynamics and provides insights for improving large-scale carbon assessments in the context of climate change.展开更多
Physiology is an important basic course for medical majors.The content of the nervous system is abstract,the theories are profound,the knowledge is updated rapidly,and it is most closely connected with clinical practi...Physiology is an important basic course for medical majors.The content of the nervous system is abstract,the theories are profound,the knowledge is updated rapidly,and it is most closely connected with clinical practice.Students generally report difficulties in understanding,resulting in low learning interest.To improve teaching quality,this study has attempted to organically integrate clinical cases,scientific research methods and classroom teaching in the teaching of the nervous system,and constructed a“clinical-research-teaching”trinity teaching model.With“clinical problem-driven,scientific research thinking-driven,teaching scenario reconstruction”as the main line,real cases,scientific research examples and cutting-edge research progress in neuroscience were introduced to stimulate students’learning interest and cultivate their scientific thinking and clinical application abilities.Practice has shown that this model can effectively improve teaching effectiveness and students’comprehensive quality.Compared with the traditional teaching model,this teaching model significantly improved students’final exam scores(p<0.01),scores of the Critical Thinking Disposition Inventory(p<0.01),and the number of approved college students’innovation and entrepreneurship projects.It is proved that the“trinity”teaching model can stimulate learning interest,cultivate integrated medical talents,and is an effective way to achieve in-depth connection between basic medicine and clinical practice.展开更多
Noninvasive detection of human physiology plays a key role for diagnosis or therapeutic assessment of various diseases.In the past,many functional modalities,such as electrocardiograph(ECG),electroencephalogram(EEG),f...Noninvasive detection of human physiology plays a key role for diagnosis or therapeutic assessment of various diseases.In the past,many functional modalities,such as electrocardiograph(ECG),electroencephalogram(EEG),fluorescence microscope,and positron emission computed tomography(PETS)have been applied to clinic for probing human heart,brain waves or tissue metabolism,owing to rapid development in fields of electromagnetism,optics or particle physics.Nowadays,a few smart sensing technologies are emerging for human physiology detection in more wide range.展开更多
The construction of the New Medical Sciences aims to cultivate interdisciplinary medical talents,placing higher demands on physiology experiment teaching.In light of the challenges of traditional teaching,such as outd...The construction of the New Medical Sciences aims to cultivate interdisciplinary medical talents,placing higher demands on physiology experiment teaching.In light of the challenges of traditional teaching,such as outdated content,a single assessment mechanism,low student engagement,and limited research experience among instructors,this study proposes a reform pathway centered on research competence development,supported by diversified evaluation methods and the deep integration of ideological and scenario-based teaching.By optimizing teaching content,introducing innovative projects,establishing a multidimensional assessment system,and strengthening faculty development,the proposed reforms effectively enhance students’Innovative ability and practical skills.This study provides theoretical insights and practical experience for training interdisciplinary medical professionals to meet the demands of the new era.展开更多
The toxic effects of different gradient concentrations of Hg2+ and Cd2+ on chlorophyll content, chlorophyll a/b value, photosynthetic O-2 evolution, respiration rate, anti-oxidase system (superoxide dismulase (SOD), c...The toxic effects of different gradient concentrations of Hg2+ and Cd2+ on chlorophyll content, chlorophyll a/b value, photosynthetic O-2 evolution, respiration rate, anti-oxidase system (superoxide dismulase (SOD), catalase (CAT), peroxidase (POD)) and ultrastructure of the cells of Azolla imbricata (Roxb.) Nakai were studied. The results showed that with Hg2+ and Cd2+ increase, chlorophyll content and chlorophyll a/b value, photosynthetic O-2 evolution decreased drastically; respiration rate peaked at 2 mg/L pollutant and declined afterwards. The activities of SOD, CAT and POD increased first and decreased afterwards except the activity of POD, which decreased with the increasing of Cd2+ concentration. Ultrastructural observation showed that the extent of ultrastructural damage was much more serious with higher pollutant concentration and longer time of stress. This resulted in swelling of chloroplast, disruption and disappearance of chloroplast membrane and disintegration of chloroplasts; swelling of cristae of mitochondria, deformation and vacuolization of mitochondria; condensation of chromatin in nucleus, dispersion of nucleolus and disruption of nuclear membrane. The experimental results showed: (1) Hg2+ and Cd2+ pollution not only destroyed physiological activities, but also caused irreversible damage to its ultrastructure, thus leading the cells to death; (2) With increase in the stress of Hg2+ and Cd2+, ultrastructural damage was related to the changes of plant physiology; (3) The toxic symptoms of plant showed an evident correlation between dose and effect; (4) The toxicity of Cd2+ on A. imbricata is heavier than that of Hg2+ under the same treatment time and concentration. The lethal concentration of Hg2+ to A. imbricata ranged from 3.5 to 4 mg/L, and that of Cd2+ ranged from 3 to 3.5 mg/L. The damage of cell ultrastructure on Anabaena azollae Strasburger was observed. The results indicated that tolerance of Azolla imbricata for Hg2+ and Cd2+ was higher than that of A. imbricata.展开更多
细胞自噬作为真核生物中高度保守的保护机制,通过降解并循环利用细胞成分,在植物生长发育和逆境响应中发挥着关键作用。本研究旨在全面阐述植物自噬的生物发生机制及其生理功能,为后续深入研究提供理论基础,并探索其在作物养分高效和抗...细胞自噬作为真核生物中高度保守的保护机制,通过降解并循环利用细胞成分,在植物生长发育和逆境响应中发挥着关键作用。本研究旨在全面阐述植物自噬的生物发生机制及其生理功能,为后续深入研究提供理论基础,并探索其在作物养分高效和抗逆育种中的应用潜力。植物自噬包括巨自噬、微自噬和分子伴侣介导自噬,其生物发生过程包括激活启动、膜延伸、自噬体形成及与液泡融合降解4个阶段,受ATG基因(autophagyrelated gene,ATG)和SnRK1/TOR(SNF1-related protein kinase,SnRK1/target of rapamycin,TOR)相关信号通路调控。Sn RK1可通过TOR依赖和非依赖方式调节自噬,ATG基因在自噬各阶段发挥关键作用,如ATG1/ATG13复合体、ATG12-ATG5-ATG16复合体、ATG8脂化等。自噬调控植物根系发育、养分高效吸收以及衰老与养分循环利用,并增强植物对氮、磷和锌、铁、镉等微量元素胁迫,以及盐、干旱、高温、水淹等非生物胁迫的耐受性。未来研究需深入解析自噬的时空调控网络,整合多组学技术,系统探索其在养分跨膜转运中的机制,及其与激素信号和营养代谢之间的交互作用,同时,结合作物育种,聚焦养分高效吸收、利用与抗逆,推动“自噬-养分高效-抗逆”协同调控,为培育高效抗逆作物提供理论支持,推动农业高效、可持续发展。展开更多
文摘BACKGROUND Liver transplantation aims to increase the survival of patients with end-stage liver diseases and improve their quality of life.The number of organs available for transplantation is lower than the demand.To provide fair organ distribution,predictive mortality scores have been developed.AIM To compare the Acute Physiology and Chronic Health Evaluation IV(APACHE IV),balance of risk(BAR),and model for end-stage liver disease(MELD)scores as predictors of mortality.METHODS Retrospective cohort study,which included 283 adult patients in the postoperative period of deceased donor liver transplantation from 2014 to 2018.RESULTS The transplant recipients were mainly male,with a mean age of 58.1 years.Donors were mostly male,with a mean age of 41.6 years.The median cold ischemia time was 3.1 hours,and the median intensive care unit stay was 5 days.For APACHE IV,a mean of 59.6 was found,BAR 10.7,and MELD 24.2.The 28-day mortality rate was 9.5%,and at 90 days,it was 3.5%.The 28-day mortality prediction for APACHE IV was very good[area under the curve(AUC):0.85,P<0.001,95%CI:0.76-0.94],P<0.001,BAR(AUC:0.70,P<0.001,95%CI:0.58–0.81),and MELD(AUC:0.66,P<0.006,95%CI:0.55-0.78),P<0.008.At 90 days,the data for APACHE IV were very good(AUC:0.80,P<0.001,95%CI:0.71–0.90)and moderate for BAR and MELD,respectively,(AUC:0.66,P<0.004,95%CI:0.55–0.77),(AUC:0.62,P<0.026,95%CI:0.51–0.72).All showed good discrimination between deaths and survivors.As for the best value for liver transplantation,it was significant only for APACHE IV(P<0.001).CONCLUSION The APACHE IV assessment score was more accurate than BAR and MELD in predicting mortality in deceased donor liver transplant recipients.
文摘Hypnosis is a promising tool in the management of various conditions,such as anxiety and chronic pain.Preliminary studies have shown that hypnosis can directly affect the cardiovascular system,as it increases parasympathetic activation and reduces sympathetic activity.However,the literature related to the effects of hypnosis on cardiovascular health is scarce,mainly due to misconceptions about hypnosis among researchers and medical professionals.This opinion paper examines the role that hypnosis may play in cardiovascular health,highlighting the physiological mechanisms behind it.The evidence suggests that hypnosis has both direct(e.g.,changes in the activity of the autonomic nervous system)and indirect(e.g.,changes in healthy behaviours)effects on the cardiovascular system;however,further studies are needed to properly define its mechanisms of action and its applicability in improving cardiovascular health.Thus,this opinion paper advocates the adoption of the term“hypno-cardiac physiology”to identify a new research area that gathers experts from neuroscience and cardiovascular science with the joint aim of seeking further understanding of the effects of hypnosis on the cardiovascular system.The adoption of a dedicated term to identify the study of the cardiovascular response to hypnosis will encourage its implementation in cardiovascular health interventions,promoting awareness of its effects among the public and the healthcare community,and promoting the formation of dedicated multidisciplinary research groups and dedicated educational training for healthcare professional interested in its applications.
文摘BACKGROUND Previous studies have reported the high predictive accuracy of 4C Mortality Score derived at hospital admission in coronavirus disease 2019(COVID-19)patients.Very few studies have assessed it at intensive care unit(ICU)admission and compared it with the Acute Physiology and Chronic Health Evaluation(APACHE)II score.There are no studies comparing its accuracy with APACHE III score.AIM To describe the characteristics and outcomes of patients admitted to ICU with COVID-19 infection and to compare the accuracy of 4C score and APACHE score in predicting mortality in these patients.METHODS We conducted this retrospective cohort study using an electronic database in a tertiary ICU in Sydney.We included all adult patients(age>16 years)admitted to ICU with COVID-19 infection over a 5-month period(July 1,2021 to November 30,2021).We collected the data on demographics,clinical characteristics,interventions and outcomes for all patients.We calculated the 4C Mortality Score for each patient using eight variables as described previously.We compared the predictive accuracy of 4C Mortality Score at hospital and ICU admission and APACHE II and III scores by area under the receiver operating characteristic curve(AUROC).We determined the optimal cut-off value for each of these scores using the‘nearest’method and its 95%confidence interval by bootstrapping.RESULTS A total of 140 patients(62%males,mean age 56±17 years,mean APACHE II score 13±57)were included in the study.Nineteen(13.6%)of 140 patients died in the hospital.Compared to survivors,the non-survivors were older,males,had more comorbidities,higher rate of mechanical ventilation and vasopressor use.The AUROC for the 4C Mortality Score at hospital and ICU admission and APACHE II and II score was 0.75,0.80.0.75 and 0.79 respectively.The optimal cut-off value for these four scores was 9,10,14 and 56 respectively.The cut-point for all the scores had higher sensitivity than specificity.CONCLUSION The 4C score at ICU admission had a higher accuracy in predicting mortality than the 4C score at hospital admission.The predictive accuracy was similar to that for APACHE III score.The 4C score at ICU admission needs to be validated in future studies.
文摘Publisher Correction to:Journal of Forestry Research(2025)36:29 https://doi.org/10.1007/s11676-025-01823-0 In Fig.4c of this article,the lower part of the figure was unintentionally cropped and incomplete during the publisher's production process.The published incorrect version and the corrected version of Fig.4 are given below.
基金support from the National Natural Science Foundation of China(Nos.42450226,42371483,and 42171308)the Natural Science Foundation of Guangdong Province,China(No.2025A1515010770)the Postdoctoral Fellowship Program of CPSF(No.GZB20240880).
文摘Vegetation annual gross primary production(AGPP),the total yearly carbon assimilation via photosynthesis,serves as a key indicator of ecosystem carbon uptake.While AGPP variations are jointly influenced by both vegetation phenology and physiology,the effectiveness of satellite-derived indicators in capturing these variations has not been fully evaluated.This study develops and evaluates the satellite-derived phenology and physiology indicators for modeling AGPP variability.We assessed the performance of satellite-derived metrics,including solar-induced chlorophyll fluorescence(SIF),leaf area index(LAI),and enhanced vegetation index(EVI),in capturing AGPP variations.Among these,SIF-based indicators exhibited the highest accuracy(Pearson's r=0.79;root mean square error=414.7 gC·m^(-2)·year^(-1)),outperforming LAI-and EVI-based indicators.To further investigate the mechanisms driving AGPP variability,we used a structural equation model based on in situ observations to quantify the direct and indirect effects of climate on AGPP through phenology and physiology.Our results reveal that vegetation physiology,particularly the seasonal maximum gross primary production,plays a more dominant role in regulating AGPP than phenology.Furthermore,we found that globally,SIF-derived phenology indicators tend to be lower than those from LAI and EVI,whereas SIF-derived physiology indicators are elevated in tropical regions and the Southern Hemisphere.These findings highlight the potential of satellite-derived indicators in advancing AGPP modeling and emphasize the predominant role of vegetation physiology in regulating ecosystem carbon uptake.This study contributes to a refined understanding of global carbon cycle dynamics and provides insights for improving large-scale carbon assessments in the context of climate change.
基金General Program of Guangdong Provincial Natural Science Foundation(Project No.:2214050002848)College Students’Innovation and Entrepreneurship Projects(Project No.:202310582018,622A0243,S202410582051)+2 种基金Key Teaching Reform Project of Jiaying University(Project No.:423A0613)2025 Teaching Quality and Teaching Reform Project of Jiaying University(Project No.:27)2023 University-level Teaching Quality and Teaching Reform Project(Project No.:ZLGC2023101)。
文摘Physiology is an important basic course for medical majors.The content of the nervous system is abstract,the theories are profound,the knowledge is updated rapidly,and it is most closely connected with clinical practice.Students generally report difficulties in understanding,resulting in low learning interest.To improve teaching quality,this study has attempted to organically integrate clinical cases,scientific research methods and classroom teaching in the teaching of the nervous system,and constructed a“clinical-research-teaching”trinity teaching model.With“clinical problem-driven,scientific research thinking-driven,teaching scenario reconstruction”as the main line,real cases,scientific research examples and cutting-edge research progress in neuroscience were introduced to stimulate students’learning interest and cultivate their scientific thinking and clinical application abilities.Practice has shown that this model can effectively improve teaching effectiveness and students’comprehensive quality.Compared with the traditional teaching model,this teaching model significantly improved students’final exam scores(p<0.01),scores of the Critical Thinking Disposition Inventory(p<0.01),and the number of approved college students’innovation and entrepreneurship projects.It is proved that the“trinity”teaching model can stimulate learning interest,cultivate integrated medical talents,and is an effective way to achieve in-depth connection between basic medicine and clinical practice.
文摘Noninvasive detection of human physiology plays a key role for diagnosis or therapeutic assessment of various diseases.In the past,many functional modalities,such as electrocardiograph(ECG),electroencephalogram(EEG),fluorescence microscope,and positron emission computed tomography(PETS)have been applied to clinic for probing human heart,brain waves or tissue metabolism,owing to rapid development in fields of electromagnetism,optics or particle physics.Nowadays,a few smart sensing technologies are emerging for human physiology detection in more wide range.
基金supported by the Key Teaching Reform and Practice Project of Pingdingshan University in 2023,titled“Research and Practice on Innovation and Entrepreneurship Pathways for Medical Students under the New Medical Discipline Framework”(Project No.2023-JYZD15)Additionally,this study received support from the Henan Province Higher Education Teaching Reform Research and Practice Project,titled“Research on the Integration Path of Medical Education and Innovation&Entrepreneurship Education under the‘Project-based+Mentorship System’Model”(Project No.2024SJGLX0495).
文摘The construction of the New Medical Sciences aims to cultivate interdisciplinary medical talents,placing higher demands on physiology experiment teaching.In light of the challenges of traditional teaching,such as outdated content,a single assessment mechanism,low student engagement,and limited research experience among instructors,this study proposes a reform pathway centered on research competence development,supported by diversified evaluation methods and the deep integration of ideological and scenario-based teaching.By optimizing teaching content,introducing innovative projects,establishing a multidimensional assessment system,and strengthening faculty development,the proposed reforms effectively enhance students’Innovative ability and practical skills.This study provides theoretical insights and practical experience for training interdisciplinary medical professionals to meet the demands of the new era.
文摘The toxic effects of different gradient concentrations of Hg2+ and Cd2+ on chlorophyll content, chlorophyll a/b value, photosynthetic O-2 evolution, respiration rate, anti-oxidase system (superoxide dismulase (SOD), catalase (CAT), peroxidase (POD)) and ultrastructure of the cells of Azolla imbricata (Roxb.) Nakai were studied. The results showed that with Hg2+ and Cd2+ increase, chlorophyll content and chlorophyll a/b value, photosynthetic O-2 evolution decreased drastically; respiration rate peaked at 2 mg/L pollutant and declined afterwards. The activities of SOD, CAT and POD increased first and decreased afterwards except the activity of POD, which decreased with the increasing of Cd2+ concentration. Ultrastructural observation showed that the extent of ultrastructural damage was much more serious with higher pollutant concentration and longer time of stress. This resulted in swelling of chloroplast, disruption and disappearance of chloroplast membrane and disintegration of chloroplasts; swelling of cristae of mitochondria, deformation and vacuolization of mitochondria; condensation of chromatin in nucleus, dispersion of nucleolus and disruption of nuclear membrane. The experimental results showed: (1) Hg2+ and Cd2+ pollution not only destroyed physiological activities, but also caused irreversible damage to its ultrastructure, thus leading the cells to death; (2) With increase in the stress of Hg2+ and Cd2+, ultrastructural damage was related to the changes of plant physiology; (3) The toxic symptoms of plant showed an evident correlation between dose and effect; (4) The toxicity of Cd2+ on A. imbricata is heavier than that of Hg2+ under the same treatment time and concentration. The lethal concentration of Hg2+ to A. imbricata ranged from 3.5 to 4 mg/L, and that of Cd2+ ranged from 3 to 3.5 mg/L. The damage of cell ultrastructure on Anabaena azollae Strasburger was observed. The results indicated that tolerance of Azolla imbricata for Hg2+ and Cd2+ was higher than that of A. imbricata.
文摘细胞自噬作为真核生物中高度保守的保护机制,通过降解并循环利用细胞成分,在植物生长发育和逆境响应中发挥着关键作用。本研究旨在全面阐述植物自噬的生物发生机制及其生理功能,为后续深入研究提供理论基础,并探索其在作物养分高效和抗逆育种中的应用潜力。植物自噬包括巨自噬、微自噬和分子伴侣介导自噬,其生物发生过程包括激活启动、膜延伸、自噬体形成及与液泡融合降解4个阶段,受ATG基因(autophagyrelated gene,ATG)和SnRK1/TOR(SNF1-related protein kinase,SnRK1/target of rapamycin,TOR)相关信号通路调控。Sn RK1可通过TOR依赖和非依赖方式调节自噬,ATG基因在自噬各阶段发挥关键作用,如ATG1/ATG13复合体、ATG12-ATG5-ATG16复合体、ATG8脂化等。自噬调控植物根系发育、养分高效吸收以及衰老与养分循环利用,并增强植物对氮、磷和锌、铁、镉等微量元素胁迫,以及盐、干旱、高温、水淹等非生物胁迫的耐受性。未来研究需深入解析自噬的时空调控网络,整合多组学技术,系统探索其在养分跨膜转运中的机制,及其与激素信号和营养代谢之间的交互作用,同时,结合作物育种,聚焦养分高效吸收、利用与抗逆,推动“自噬-养分高效-抗逆”协同调控,为培育高效抗逆作物提供理论支持,推动农业高效、可持续发展。
