Understanding the dynamics of phytoplankton communities in coastal zones is crucial for the management and conservation of coastal ecosystems.Previous research indicated that the phytoplankton community structure and ...Understanding the dynamics of phytoplankton communities in coastal zones is crucial for the management and conservation of coastal ecosystems.Previous research indicated that the phytoplankton community structure and dominant taxa in the Bohai Sea(BHS)have exhibited significant shifts from the 1990s to the early 2010s in response to environmental changes,especially the change in nutrient structure.This study comprehensively investigated the variations in net-collected phytoplankton(>76μm)community structure,diversity,and environmental factors in the BHS during the late summers of 2011-2020,aiming to understand the recent trend in phytoplankton community structure and to explore the interactions between the communities and the environment.During the study period,the nutrient status in the BHS was characterized by a decrease in dissolved inorganic nitrogen(DIN)concentration,an increase in dissolved inorganic phosphorus(DIP)concentration,and a return of the nitrogen-to-phosphorus(N/P)molar ratio(hereinafter referred to as N/P ratio)to the Redfield ratio since 2016.The eutrophication index(EI)in the BHS remained stable and was generally at a low level(<1).The Dia/Dino index fluctuated but did not show an obvious trend.Overall,the eutrophication,the imbalance in nutrient ratio,and the shift in phytoplankton community structure did not continue during the study period.The increased abundance of phytoplankton was strongly associated with elevated concentrations of DIN,as well as higher N/P and nitrogen-to-silicon(N/Si)ratios,whereas the greater diversity was strongly linked to higher concentrations of DIP.Diatoms and dinoflagellates showed significant differences in their interactions with the environment,and their relative dominance was related to water column depth and stratification intensity;their impacts on the phytoplankton community diversity were also significantly different.The variations of certain dominant species,i.e.,Skeletonema costatum,Paralia sulcata,and Tripos longipes,exhibited strong links to the changes in nutrient structure in the BHS.The findings of this study contribute to understanding the regional environmental changes and provide insights into the adaptive strategies of coastal ecosystems in response to environmental shifts and fluctuations.展开更多
Vascular tissue serves as the channel for nutrient transport and signal transduc-tion between different organs in plants. To study molecular identity and behavior of mobile substances transmitted between organs via ...Vascular tissue serves as the channel for nutrient transport and signal transduc-tion between different organs in plants. To study molecular identity and behavior of mobile substances transmitted between organs via vascular tissue, it is necessary to collect exudate from stem or other organs. Modifed stem-cutting method for exudate collection in soybean was used in this study by selecting the optimum sampling time and position, using reagents preventing RNA degradation, etc. Diurnal dynamics analysis of exudate emission was found to be the highest during 10：00-10：10 am. Totally 15 μL pure exudate was collected from the stem cut between cotyledonary and unifoliolate nodes at V1 stage （unifoliolate just expanded） of young soybean seedling. Improved TRIzol method was used to extract RNA and protein from stem exudate. A phloem specifc gene of Glycine max sieve element occlusion s, SEO, in exudate samples was successfully amplifed by RT-PCR, which comfrmed the success of RNA extraction. SDS-PAGE showed the majority of proteins in exudate were of low molec-ular weight. Method proposed in this study would facilitate collection of quality exudate and enhance further investigation of mobile substances in soybean.展开更多
基金The National Natural Science Foundation of China under contract No.42206161the Natural Science Foundation of Hebei Province under contract No.D2022407004+1 种基金the Science Research Project of Hebei Education Department under contract No.QN2022167the Open Fund Project of Hebei Key Laboratory of Ocean Dynamics,Resources and Environments under contract No.HBHY04.
文摘Understanding the dynamics of phytoplankton communities in coastal zones is crucial for the management and conservation of coastal ecosystems.Previous research indicated that the phytoplankton community structure and dominant taxa in the Bohai Sea(BHS)have exhibited significant shifts from the 1990s to the early 2010s in response to environmental changes,especially the change in nutrient structure.This study comprehensively investigated the variations in net-collected phytoplankton(>76μm)community structure,diversity,and environmental factors in the BHS during the late summers of 2011-2020,aiming to understand the recent trend in phytoplankton community structure and to explore the interactions between the communities and the environment.During the study period,the nutrient status in the BHS was characterized by a decrease in dissolved inorganic nitrogen(DIN)concentration,an increase in dissolved inorganic phosphorus(DIP)concentration,and a return of the nitrogen-to-phosphorus(N/P)molar ratio(hereinafter referred to as N/P ratio)to the Redfield ratio since 2016.The eutrophication index(EI)in the BHS remained stable and was generally at a low level(<1).The Dia/Dino index fluctuated but did not show an obvious trend.Overall,the eutrophication,the imbalance in nutrient ratio,and the shift in phytoplankton community structure did not continue during the study period.The increased abundance of phytoplankton was strongly associated with elevated concentrations of DIN,as well as higher N/P and nitrogen-to-silicon(N/Si)ratios,whereas the greater diversity was strongly linked to higher concentrations of DIP.Diatoms and dinoflagellates showed significant differences in their interactions with the environment,and their relative dominance was related to water column depth and stratification intensity;their impacts on the phytoplankton community diversity were also significantly different.The variations of certain dominant species,i.e.,Skeletonema costatum,Paralia sulcata,and Tripos longipes,exhibited strong links to the changes in nutrient structure in the BHS.The findings of this study contribute to understanding the regional environmental changes and provide insights into the adaptive strategies of coastal ecosystems in response to environmental shifts and fluctuations.
基金funded by China Agriculture Research system(CARS-04)CAAS Agricultural Sciences and Technology Innovation Project
文摘Vascular tissue serves as the channel for nutrient transport and signal transduc-tion between different organs in plants. To study molecular identity and behavior of mobile substances transmitted between organs via vascular tissue, it is necessary to collect exudate from stem or other organs. Modifed stem-cutting method for exudate collection in soybean was used in this study by selecting the optimum sampling time and position, using reagents preventing RNA degradation, etc. Diurnal dynamics analysis of exudate emission was found to be the highest during 10：00-10：10 am. Totally 15 μL pure exudate was collected from the stem cut between cotyledonary and unifoliolate nodes at V1 stage （unifoliolate just expanded） of young soybean seedling. Improved TRIzol method was used to extract RNA and protein from stem exudate. A phloem specifc gene of Glycine max sieve element occlusion s, SEO, in exudate samples was successfully amplifed by RT-PCR, which comfrmed the success of RNA extraction. SDS-PAGE showed the majority of proteins in exudate were of low molec-ular weight. Method proposed in this study would facilitate collection of quality exudate and enhance further investigation of mobile substances in soybean.
