[ Objective ] Study on the changes of chlorophyll fluorescence parameters in Cinnamomumjaponicum var. chenii under NaCl stress. [ Method ] The seedling growth increment, chlorophyll content and chlorophyll fluorescenc...[ Objective ] Study on the changes of chlorophyll fluorescence parameters in Cinnamomumjaponicum var. chenii under NaCl stress. [ Method ] The seedling growth increment, chlorophyll content and chlorophyll fluorescence parameters in leaves of 1-year old Cinnamomum japonicum var. chenii were investigated in field experiment. [ Result] Under NaC1 stress, seedling growth increment reduced and the chlorophyll content decreased to a stable value ; changes of Fv/Fm and Fv/Fo showed identical increasing trend and double peak type. With the aggravation of salt stress, most variations were observed in Fo, correlations among chlorophyll fluorescence parameters presented "rise-drop" trend (in.the treatment of 7 g/L NaCl). [ Conclusion] Cirmamomum japonicum vat. chenii is endowed with strong salt resistance and wide adaptability.展开更多
Over the last decades, the usage of PAM (pulse amplitude modulated) fluorometers for assessment of chlorophyll-a fluorescence variations became widely applied on marine macroalgae physiology and ecophysiology resear...Over the last decades, the usage of PAM (pulse amplitude modulated) fluorometers for assessment of chlorophyll-a fluorescence variations became widely applied on marine macroalgae physiology and ecophysiology researches. Due to the increased use of these methods, a large number of studies, mainly relating to macroalgae ecology and physiology were worldwide reported. In this context, it was also created a mismatch of concepts about fluorescence of the chlorophyll-a and its application. Under this background, this study compile and summarize the state of the art knowledge regarding to the chlorophyll fluorescence, contextualizing the use of the PAM method with the main factors regulating photosynthesis (light, temperature, salinity nitrogen and phosphorus) in marine macroalgae. Moreover, this study also references the most used terms and shows some examples found in literature about the applicability of fluorescence parameters. The herein findings and the discussed examples, helps to emphasize the importance of fluorescence usage, that highlights the understanding of photosynthetic responses in macroalgal physiology and ecology.展开更多
The purpose of this study was to explore influence of abiotic factors, such as high temperature, water deficiency and high solar radiation on the photomembrane of grapevine leaves. Grapevine leaves were collected from...The purpose of this study was to explore influence of abiotic factors, such as high temperature, water deficiency and high solar radiation on the photomembrane of grapevine leaves. Grapevine leaves were collected from variety Rkatsiteli (Vitis vinifera) and placed at a temperature of +45 ℃ and +55 ℃ for 5 rain, respectively. The relative volume of water in leaves was gradually reduced to 50%, and then leaves were irradiated with 6,000 pmol/m2.s of white light. Changes provoked by stressful abiotie factors were determined using rapid and delayed chlorophyll fluorescence methods. It was shown that value of variable component of chlorophyll fluorescence (Fv), intensity of electron transport between the photosystems (ETR), intensity of expended electrons in carboxylation (ETRn) and oxygenation (ETRp) and index of non-photochemical quenching (NPQ), allow studying molecular mechanisms of the impact of abiotic factors and the resulting damage degree. Based on delayed and rapid fluorescence data, it was demonstrated that temperature of +45 ℃ adversely affects oxygen production system and CO2 assimilation mechanisms, while at +55 ℃, the ETR decreases. Reduction of relative water volume in leaves up to 50%-55% leads to sharp reduction in ETR and inhibition of photosynthesis. In case of irradiation of leaves with high-intensity light of 6,000 μmol/m2.s, NPQ of light falling on a leaf increases, thus protecting photosynthesis apparatus from damage.展开更多
基金Key Scientific Research Project of Zhejiang Province (2005G12004)~~
文摘[ Objective ] Study on the changes of chlorophyll fluorescence parameters in Cinnamomumjaponicum var. chenii under NaCl stress. [ Method ] The seedling growth increment, chlorophyll content and chlorophyll fluorescence parameters in leaves of 1-year old Cinnamomum japonicum var. chenii were investigated in field experiment. [ Result] Under NaC1 stress, seedling growth increment reduced and the chlorophyll content decreased to a stable value ; changes of Fv/Fm and Fv/Fo showed identical increasing trend and double peak type. With the aggravation of salt stress, most variations were observed in Fo, correlations among chlorophyll fluorescence parameters presented "rise-drop" trend (in.the treatment of 7 g/L NaCl). [ Conclusion] Cirmamomum japonicum vat. chenii is endowed with strong salt resistance and wide adaptability.
文摘Over the last decades, the usage of PAM (pulse amplitude modulated) fluorometers for assessment of chlorophyll-a fluorescence variations became widely applied on marine macroalgae physiology and ecophysiology researches. Due to the increased use of these methods, a large number of studies, mainly relating to macroalgae ecology and physiology were worldwide reported. In this context, it was also created a mismatch of concepts about fluorescence of the chlorophyll-a and its application. Under this background, this study compile and summarize the state of the art knowledge regarding to the chlorophyll fluorescence, contextualizing the use of the PAM method with the main factors regulating photosynthesis (light, temperature, salinity nitrogen and phosphorus) in marine macroalgae. Moreover, this study also references the most used terms and shows some examples found in literature about the applicability of fluorescence parameters. The herein findings and the discussed examples, helps to emphasize the importance of fluorescence usage, that highlights the understanding of photosynthetic responses in macroalgal physiology and ecology.
文摘The purpose of this study was to explore influence of abiotic factors, such as high temperature, water deficiency and high solar radiation on the photomembrane of grapevine leaves. Grapevine leaves were collected from variety Rkatsiteli (Vitis vinifera) and placed at a temperature of +45 ℃ and +55 ℃ for 5 rain, respectively. The relative volume of water in leaves was gradually reduced to 50%, and then leaves were irradiated with 6,000 pmol/m2.s of white light. Changes provoked by stressful abiotie factors were determined using rapid and delayed chlorophyll fluorescence methods. It was shown that value of variable component of chlorophyll fluorescence (Fv), intensity of electron transport between the photosystems (ETR), intensity of expended electrons in carboxylation (ETRn) and oxygenation (ETRp) and index of non-photochemical quenching (NPQ), allow studying molecular mechanisms of the impact of abiotic factors and the resulting damage degree. Based on delayed and rapid fluorescence data, it was demonstrated that temperature of +45 ℃ adversely affects oxygen production system and CO2 assimilation mechanisms, while at +55 ℃, the ETR decreases. Reduction of relative water volume in leaves up to 50%-55% leads to sharp reduction in ETR and inhibition of photosynthesis. In case of irradiation of leaves with high-intensity light of 6,000 μmol/m2.s, NPQ of light falling on a leaf increases, thus protecting photosynthesis apparatus from damage.