Photosynthetic rate (Pn) of plants is simultaneously affected by photosynthetically active radiation (PAR) and maximum yield of primary photochemistry (Fv/Fm). In order to explore the quantitative relationship between...Photosynthetic rate (Pn) of plants is simultaneously affected by photosynthetically active radiation (PAR) and maximum yield of primary photochemistry (Fv/Fm). In order to explore the quantitative relationship between Pn, PAR and Fv/Fm, those parameters were simultaneously measured for different plant species (maize, sunflower, daylily and alfalfa), growth stages and irrigation treatments. Results indicated that the diurnal variation of Pn had no significant correlation with that of Fv/Fm. Mean diurnal values of Pn were linearly correlated with those of Fv/Fm among the different irrigation treatments of alfalfa (p < 0.05), but this linear correlation was not observed among the different species. There was a positive relationship between Pn and Fv/Fm only at midday (12:00 and 14:00) (p < 0.01). A significant linear relationship was observed between the diurnal variation of Pn and PAR × Fv/Fm (p < 0.05), this law was suitable for the different species, and the different growth stages and the different irrigation treatments of the same species. This study confirms that Pn is significantly related to the photochemical energy (PAR × Fv/Fm), the light energy directly used in photochemical reactions of plants.展开更多
Marine heatwaves(MHWs)caused by anthropogenic climate change are becoming a key driver of change at the ecosystem level.Thermal conditions experienced by marine organisms across their distribution,particularly towards...Marine heatwaves(MHWs)caused by anthropogenic climate change are becoming a key driver of change at the ecosystem level.Thermal conditions experienced by marine organisms across their distribution,particularly towards the equator,are likely to approach their physiological limits,resulting in extensive mortality and subsequent changes at the population level.Populations at the margins of their species’distribution are thought to be more sensitive to climate-induced environmental pressures than central populations,but our understanding of variability in fitness-related physiological traits in trailing versus leading-edge populations is limited.In a laboratory simulation study,we tested whether two leading(Iceland)and two trailing(Spain)peripheral populations of the intertidal macroalga Corallina officinalis display different levels of maximum potential quantum efficiency(Fv/Fm)resilience to current and future winter MHWs scenarios.Our study revealed that ongoing and future local winter MHWs will not negatively affect leading-edge populations of C.officinalis,which exhibited stable photosynthetic efficiency throughout the study.Trailing edge populations showed a positive though non-significant trend in photosynthetic efficiency throughout winter MHWs exposure.Poleward and equatorward populations did not produce significantly different results,with winter MHWs having no negative affect on Fv/Fm of either population.Additionally,we found no long-term regional or population-level influence of a winter MHWs on this species’photosynthetic efficiency.Thus,we found no statistically significant difference in thermal stress responses between leading and trailing populations.Nonetheless,C.officinalis showed a trend towards higher stress responses in southern than northern populations.Because responses rest on a variety of local population traits,they are difficult to predict based solely on thermal pressures.展开更多
文摘Photosynthetic rate (Pn) of plants is simultaneously affected by photosynthetically active radiation (PAR) and maximum yield of primary photochemistry (Fv/Fm). In order to explore the quantitative relationship between Pn, PAR and Fv/Fm, those parameters were simultaneously measured for different plant species (maize, sunflower, daylily and alfalfa), growth stages and irrigation treatments. Results indicated that the diurnal variation of Pn had no significant correlation with that of Fv/Fm. Mean diurnal values of Pn were linearly correlated with those of Fv/Fm among the different irrigation treatments of alfalfa (p < 0.05), but this linear correlation was not observed among the different species. There was a positive relationship between Pn and Fv/Fm only at midday (12:00 and 14:00) (p < 0.01). A significant linear relationship was observed between the diurnal variation of Pn and PAR × Fv/Fm (p < 0.05), this law was suitable for the different species, and the different growth stages and the different irrigation treatments of the same species. This study confirms that Pn is significantly related to the photochemical energy (PAR × Fv/Fm), the light energy directly used in photochemical reactions of plants.
基金The Fundação para a Ciência e Tecnologia(FCT-MEC,Portugal)under contract No.UIDB/04326/2020 awarded to Gerardo Zardithe South African Research Chairs Initiative(SARChI)of the Department of Science and Technology and the National Research Foundation of South Africa under contract No.64801 awarded to Christopher McQuaid+1 种基金the Fund of European Union’s Horizon 2020 Research and Innovation Programme under the Marie Skłodowska-Curie contract No.101034329the WINNINGNormandy Program supported by the Normandy Region for Gerardo Zardi.
文摘Marine heatwaves(MHWs)caused by anthropogenic climate change are becoming a key driver of change at the ecosystem level.Thermal conditions experienced by marine organisms across their distribution,particularly towards the equator,are likely to approach their physiological limits,resulting in extensive mortality and subsequent changes at the population level.Populations at the margins of their species’distribution are thought to be more sensitive to climate-induced environmental pressures than central populations,but our understanding of variability in fitness-related physiological traits in trailing versus leading-edge populations is limited.In a laboratory simulation study,we tested whether two leading(Iceland)and two trailing(Spain)peripheral populations of the intertidal macroalga Corallina officinalis display different levels of maximum potential quantum efficiency(Fv/Fm)resilience to current and future winter MHWs scenarios.Our study revealed that ongoing and future local winter MHWs will not negatively affect leading-edge populations of C.officinalis,which exhibited stable photosynthetic efficiency throughout the study.Trailing edge populations showed a positive though non-significant trend in photosynthetic efficiency throughout winter MHWs exposure.Poleward and equatorward populations did not produce significantly different results,with winter MHWs having no negative affect on Fv/Fm of either population.Additionally,we found no long-term regional or population-level influence of a winter MHWs on this species’photosynthetic efficiency.Thus,we found no statistically significant difference in thermal stress responses between leading and trailing populations.Nonetheless,C.officinalis showed a trend towards higher stress responses in southern than northern populations.Because responses rest on a variety of local population traits,they are difficult to predict based solely on thermal pressures.
