Chlorophyll fluorescence,particularly the parameter F_(v)/F_(m),has emerged as a reliable,non-invasive indicator of the maximum quantum efficiency of Photosystem II(PSII)in plants.Over the past decade,significant rese...Chlorophyll fluorescence,particularly the parameter F_(v)/F_(m),has emerged as a reliable,non-invasive indicator of the maximum quantum efficiency of Photosystem II(PSII)in plants.Over the past decade,significant research has leveraged F_(v)/F_(m) to evaluate plant responses to a wide range of biotic and abiotic stresses,as well as to support crop improvement and ecological monitoring.This review synthesizes recent progress in understanding the physiological basis,measurement techniques,and applied significance of F_(v)/F_(m) across diverse plant systems.We highlight methodological advancements in fluorescence imaging and remote sensing,identify consistent patterns and contrasting findings in stress-response studies,and explore how F_(v)/F_(m) correlates with other physiological and molecular indicators.Despite its widespread use,challenges remain regarding data interpretation,environmental variability,and integration with multi-parameter models.This review also addresses critical knowledge gaps and proposes future research directions,including AI-driven analysis,a least-squares support vector machine(LSSVM)model,and high-resolution phenotyping.By consolidating findings from recent literature,this work provides a comprehensive reference for researchers aiming to harness F_(v)/F_(m) in both basic and applied plant sciences.展开更多
The H9N2 subtype avian influenza virus(AIV)continues to propagate and undergo evolution within China,thereby posing a significant threat to the poultry industry.This study encompassed the collection of 436 samples and...The H9N2 subtype avian influenza virus(AIV)continues to propagate and undergo evolution within China,thereby posing a significant threat to the poultry industry.This study encompassed the collection of 436 samples and swabs in East China over the period spanning 2018 to 2019,from which 31 strains of the H9N2 subtype viruses were isolated and purified.We revealed that the HA and NA genes of the 31 isolates categorized within the Y280 branch,while the PB2 and M genes were associated with the G1 branch,and the remaining genes aligned with the F/98 branch.Despite this alignment,antigenic mapping demonstrated differences between the 2018 and 2019 strains,with the early vaccine strains displaying low serological reactivity toward these isolates.Notably,the CK/SH/49/19 isolate exhibited lethality in mice,characterized by a PB2 E627V mutation and a HA deletion at amino acid position 217.Mechanistically,in vitro studies showed that the influenza virus CK/SH/49/19 carrying PB2627V and HA 217M mutations displayed enhanced replication capacity,attributed to the heightened activity of the polymerase with PB2627V.Moreover,the absence of the amino acid at the HA 217 site obstructed viral adsorption and internalization,resulted in lower activation pH,and impeded the virus budding process.Critically,in vivo experiments revealed that CK/SH/49/19(PB2627V,HA 217Δ)triggered a robust activation of interferon response and interferon-stimulated genes.This study furnished a theoretical foundation for the scientific prevention and control strategies against H9N2 subtype avian influenza.展开更多
研究城市径流水质变化及初期冲刷效应对控制与治理城市径流污染具有重要指导意义.对塘西河上游6次降雨径流水质水量进行监测分析,计算次降雨径流平均浓度(EMC)和单位面积次降雨径流污染负荷(EPL),作M(V)曲线图研究初期冲刷现象.结果表明...研究城市径流水质变化及初期冲刷效应对控制与治理城市径流污染具有重要指导意义.对塘西河上游6次降雨径流水质水量进行监测分析,计算次降雨径流平均浓度(EMC)和单位面积次降雨径流污染负荷(EPL),作M(V)曲线图研究初期冲刷现象.结果表明:降雨径流中悬浮物(SS)、化学需氧量(CODCr)和总磷(TP)的EMC值相对较大;SS的EMC值波动最为显著;总氮(TN)、TP、COD_(Cr)、SS间的EMC值均呈正相关;TN的EMC值与降雨量呈负相关性.各污染物EPL值与各降雨特征间均呈正相关性,经估算2015年研究区在6-8月共有10.38 tTN、2.29 tTP、1022.43 t SS、161.70 t CODCr和5.18 t NH_3-N随降雨径流排入巢湖;降雨量和雨前干期是城市径流污染的主要影响因素;以FF50>50为初期冲刷效应判别依据,5种污染物均有初期冲刷效应出现,冲刷程度表现为SS>CODCr>TP>TN>NH_3-N;各水质指标的初期冲刷强度与降雨特征之间无相关性;雨型对初期冲刷现象影响较大;当降雨强度达1.36 mm/h即有径流汇集流出时开始截流,截流时间取440 min,截取的最大径流量取224319.14 m^3.展开更多
根据支持向量机(SVM)的计算理论,结合高光谱影像的数据特点,利用最近点算法(NPA)求两类最优超平面,为每类设立一个合理的权指标,提出了基于NPA的加权"1 V m"SVM算法来实现高光谱遥感影像多分类,降低了计算的复杂度和计算量,...根据支持向量机(SVM)的计算理论,结合高光谱影像的数据特点,利用最近点算法(NPA)求两类最优超平面,为每类设立一个合理的权指标,提出了基于NPA的加权"1 V m"SVM算法来实现高光谱遥感影像多分类,降低了计算的复杂度和计算量,提高了SVM高光谱遥感影像分类的可操作性和分类效率。展开更多
基金supported by the National Natural Science Foundation of China(32000197,32200429).
文摘Chlorophyll fluorescence,particularly the parameter F_(v)/F_(m),has emerged as a reliable,non-invasive indicator of the maximum quantum efficiency of Photosystem II(PSII)in plants.Over the past decade,significant research has leveraged F_(v)/F_(m) to evaluate plant responses to a wide range of biotic and abiotic stresses,as well as to support crop improvement and ecological monitoring.This review synthesizes recent progress in understanding the physiological basis,measurement techniques,and applied significance of F_(v)/F_(m) across diverse plant systems.We highlight methodological advancements in fluorescence imaging and remote sensing,identify consistent patterns and contrasting findings in stress-response studies,and explore how F_(v)/F_(m) correlates with other physiological and molecular indicators.Despite its widespread use,challenges remain regarding data interpretation,environmental variability,and integration with multi-parameter models.This review also addresses critical knowledge gaps and proposes future research directions,including AI-driven analysis,a least-squares support vector machine(LSSVM)model,and high-resolution phenotyping.By consolidating findings from recent literature,this work provides a comprehensive reference for researchers aiming to harness F_(v)/F_(m) in both basic and applied plant sciences.
基金supported by National Natural Science Foundation of China[Grant number:32272992(JP),31772775(JP)]National Key Research and Development Program of China[Grant number:2021YFD1800205(JP)].
文摘The H9N2 subtype avian influenza virus(AIV)continues to propagate and undergo evolution within China,thereby posing a significant threat to the poultry industry.This study encompassed the collection of 436 samples and swabs in East China over the period spanning 2018 to 2019,from which 31 strains of the H9N2 subtype viruses were isolated and purified.We revealed that the HA and NA genes of the 31 isolates categorized within the Y280 branch,while the PB2 and M genes were associated with the G1 branch,and the remaining genes aligned with the F/98 branch.Despite this alignment,antigenic mapping demonstrated differences between the 2018 and 2019 strains,with the early vaccine strains displaying low serological reactivity toward these isolates.Notably,the CK/SH/49/19 isolate exhibited lethality in mice,characterized by a PB2 E627V mutation and a HA deletion at amino acid position 217.Mechanistically,in vitro studies showed that the influenza virus CK/SH/49/19 carrying PB2627V and HA 217M mutations displayed enhanced replication capacity,attributed to the heightened activity of the polymerase with PB2627V.Moreover,the absence of the amino acid at the HA 217 site obstructed viral adsorption and internalization,resulted in lower activation pH,and impeded the virus budding process.Critically,in vivo experiments revealed that CK/SH/49/19(PB2627V,HA 217Δ)triggered a robust activation of interferon response and interferon-stimulated genes.This study furnished a theoretical foundation for the scientific prevention and control strategies against H9N2 subtype avian influenza.
文摘研究城市径流水质变化及初期冲刷效应对控制与治理城市径流污染具有重要指导意义.对塘西河上游6次降雨径流水质水量进行监测分析,计算次降雨径流平均浓度(EMC)和单位面积次降雨径流污染负荷(EPL),作M(V)曲线图研究初期冲刷现象.结果表明:降雨径流中悬浮物(SS)、化学需氧量(CODCr)和总磷(TP)的EMC值相对较大;SS的EMC值波动最为显著;总氮(TN)、TP、COD_(Cr)、SS间的EMC值均呈正相关;TN的EMC值与降雨量呈负相关性.各污染物EPL值与各降雨特征间均呈正相关性,经估算2015年研究区在6-8月共有10.38 tTN、2.29 tTP、1022.43 t SS、161.70 t CODCr和5.18 t NH_3-N随降雨径流排入巢湖;降雨量和雨前干期是城市径流污染的主要影响因素;以FF50>50为初期冲刷效应判别依据,5种污染物均有初期冲刷效应出现,冲刷程度表现为SS>CODCr>TP>TN>NH_3-N;各水质指标的初期冲刷强度与降雨特征之间无相关性;雨型对初期冲刷现象影响较大;当降雨强度达1.36 mm/h即有径流汇集流出时开始截流,截流时间取440 min,截取的最大径流量取224319.14 m^3.
