[Objectives]This study was conducted to investigate the differences of photosynthetic physiological characteristics of different varieties(strains),which will provide a theoretical basis for high photosynthesis effici...[Objectives]This study was conducted to investigate the differences of photosynthetic physiological characteristics of different varieties(strains),which will provide a theoretical basis for high photosynthesis efficiency breeding and application in Chinese chestnut.[Methods]Six Chinese chestnut varieties of Castanea mollissima‘Yanbao’,C.mollissima‘Yanqiu’,C.mollissima‘Yanchang’,C.mollissima‘Yanjia’,C.mollissima‘Qianxi 37’,and C.mollissima‘Hybrid 22’were used as the materials.Using the portable photosynthesis system Li-6400,we measured the photosynthetic characteristics and diurnal variation of leaf samples of six different chestnut varieties or strains.We fitted the light response curves and photosynthetic parameters using the leaf floating model.Additionally,we determined the chlorophyll content in the leaves using a UV-visible spectrophotometer.[Results]Among the six chestnut varieties or strains,‘Yanqiu’exhibited a significantly higher photosynthetic light saturation point(P LSP)compared to other five varieties,and‘Hybrid 22’ranked second,indicating that these two varieties had the strongest adaptation to high light intensity.The photosynthetic light compensation point(P LCP)of‘Yanchang’was significantly higher than other five varieties,and"Qianxi 37"ranked second,indicating that these two varieties had the strongest adaptation to low light intensity.Additionally,they exhibited higher chlorophyll content and maintained good photosynthetic characteristics even in shaded environments with weak light stress.Varieties‘Yanbao’and‘Yanjia’showed higher P LSP and lower P LCP,indicating that these two varieties have a wider range of adaptation to light intensity.They were capable of efficiently utilizing light across a broader spectrum of intensities.‘Yanqiu’had the highest maximum net photosynthetic rate(P n,max)and the lowest dark respiration rate(R d),along with the highest chlorophyll content.It indicated that‘Yanqiu’has strong photosynthetic capacity and organic matter accumulation ability.It also had the highest P LSP,enabling it to fully utilize the high light environment of the Yanshan Mountains and possessed high light efficiency characteristics.The P n,max of‘Yanqiu’was significantly higher than other varieties.‘Hybrid 22’and‘Yanbao’also exhibited significantly higher P n,max compared with‘Yanjia’and‘Qianxi 37’.‘Yanchang’had the lowest P n,max.The order of P n,max among the six chestnut varieties or strains was as follows:‘Yanqiu’>‘Hybrid 22’>‘Yanbao’>‘Yanjia’>‘Qianxi 37’>‘Yanchang’.[Conclusions]展开更多
Solar-induced chlorophyll fluorescence(SIF)has shown promise in estimating gross primary production(GPP);however,there is a lack of global GPP datasets directly utilizing SIF with models possessing clear expression of...Solar-induced chlorophyll fluorescence(SIF)has shown promise in estimating gross primary production(GPP);however,there is a lack of global GPP datasets directly utilizing SIF with models possessing clear expression of the biophysical and biological processes in photosynthesis.This study introduces a new global 0.05°SIF-based GPP dataset(CMLR GPP,based on Canopy-scale Mechanistic Light Reaction model)using TROPOMI observations.A modified mechanistic light response model was employed at the canopy scale to generate this dataset.The canopy qL(opened fraction of photosynthesis II reaction centers),required by the CMLR model,was parameterized using a random forest model.The CMLR GPP estimates showed a strong correlation with tower-based GPP(R^(2)=0.72)in the validation dataset,and it showed comparable performance with other global datasets such as Boreal Ecosystem Productivity Simulator(BEPS)GPP,FluxSat GPP,and GOSIF(global,OCO-2-based SIF product)GPP at a global scale.The high accuracy of CMLR GPP was consistent across various normalized difference vegetation index,vapor pressure deficit,and temperature conditions,as well as different plant functional types and most months of the year.In conclusion,CMLR GPP is a novel global GPP dataset based on mechanistic frameworks,whose availability is expected to contribute to future research in ecological and geobiological regions.展开更多
基金Supported by National Key R&D Program of China (2022YFD2200400)Doctoral Started Fund of Hebei Normal University of Science and Technology (2023YB026)Hebei Qinglong Chinese Chestnut Technological Yard.
文摘[Objectives]This study was conducted to investigate the differences of photosynthetic physiological characteristics of different varieties(strains),which will provide a theoretical basis for high photosynthesis efficiency breeding and application in Chinese chestnut.[Methods]Six Chinese chestnut varieties of Castanea mollissima‘Yanbao’,C.mollissima‘Yanqiu’,C.mollissima‘Yanchang’,C.mollissima‘Yanjia’,C.mollissima‘Qianxi 37’,and C.mollissima‘Hybrid 22’were used as the materials.Using the portable photosynthesis system Li-6400,we measured the photosynthetic characteristics and diurnal variation of leaf samples of six different chestnut varieties or strains.We fitted the light response curves and photosynthetic parameters using the leaf floating model.Additionally,we determined the chlorophyll content in the leaves using a UV-visible spectrophotometer.[Results]Among the six chestnut varieties or strains,‘Yanqiu’exhibited a significantly higher photosynthetic light saturation point(P LSP)compared to other five varieties,and‘Hybrid 22’ranked second,indicating that these two varieties had the strongest adaptation to high light intensity.The photosynthetic light compensation point(P LCP)of‘Yanchang’was significantly higher than other five varieties,and"Qianxi 37"ranked second,indicating that these two varieties had the strongest adaptation to low light intensity.Additionally,they exhibited higher chlorophyll content and maintained good photosynthetic characteristics even in shaded environments with weak light stress.Varieties‘Yanbao’and‘Yanjia’showed higher P LSP and lower P LCP,indicating that these two varieties have a wider range of adaptation to light intensity.They were capable of efficiently utilizing light across a broader spectrum of intensities.‘Yanqiu’had the highest maximum net photosynthetic rate(P n,max)and the lowest dark respiration rate(R d),along with the highest chlorophyll content.It indicated that‘Yanqiu’has strong photosynthetic capacity and organic matter accumulation ability.It also had the highest P LSP,enabling it to fully utilize the high light environment of the Yanshan Mountains and possessed high light efficiency characteristics.The P n,max of‘Yanqiu’was significantly higher than other varieties.‘Hybrid 22’and‘Yanbao’also exhibited significantly higher P n,max compared with‘Yanjia’and‘Qianxi 37’.‘Yanchang’had the lowest P n,max.The order of P n,max among the six chestnut varieties or strains was as follows:‘Yanqiu’>‘Hybrid 22’>‘Yanbao’>‘Yanjia’>‘Qianxi 37’>‘Yanchang’.[Conclusions]
基金supported by the National Natural Science Foundation of China(grant numbers 41825002 and 42071310)supported by the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)under Germany’s Excellence Strategy-EXC 2070-390732324.
文摘Solar-induced chlorophyll fluorescence(SIF)has shown promise in estimating gross primary production(GPP);however,there is a lack of global GPP datasets directly utilizing SIF with models possessing clear expression of the biophysical and biological processes in photosynthesis.This study introduces a new global 0.05°SIF-based GPP dataset(CMLR GPP,based on Canopy-scale Mechanistic Light Reaction model)using TROPOMI observations.A modified mechanistic light response model was employed at the canopy scale to generate this dataset.The canopy qL(opened fraction of photosynthesis II reaction centers),required by the CMLR model,was parameterized using a random forest model.The CMLR GPP estimates showed a strong correlation with tower-based GPP(R^(2)=0.72)in the validation dataset,and it showed comparable performance with other global datasets such as Boreal Ecosystem Productivity Simulator(BEPS)GPP,FluxSat GPP,and GOSIF(global,OCO-2-based SIF product)GPP at a global scale.The high accuracy of CMLR GPP was consistent across various normalized difference vegetation index,vapor pressure deficit,and temperature conditions,as well as different plant functional types and most months of the year.In conclusion,CMLR GPP is a novel global GPP dataset based on mechanistic frameworks,whose availability is expected to contribute to future research in ecological and geobiological regions.
