Increasing leaf photosynthesis per area（A） is of great importance to achieve yield further improvement. The aim of this study was to exploit varietal difference in A and its correlation with specific leaf weight（SL...Increasing leaf photosynthesis per area（A） is of great importance to achieve yield further improvement. The aim of this study was to exploit varietal difference in A and its correlation with specific leaf weight（SLW）. Twelve rice cultivars, including 6 indica and 6 japonica varieties, were pot-grown under two N treatments, low N（LN） and sufficient N（SN）. Leaf photosynthesis and related parameters were measured at tillering stage. Compared with LN treatment, A, stomatal conductance（g_s）, mesophyll conductance（g_m）, leaf N content（N_（area））, and chlorophyll content were significantly improved under SN treatment, while SLW and photosynthetic N use efficiency（PNUE） were generally decreased. Varietal difference in A was positively related to both g_s and g_m, but not related to N_（area）. This resulted in a low PNUE in high N_（area） leaves. Varietal difference in PNUE was generally negatively related to SLW. Response of PNUE to N supply varied among different rice cultivars, and interestingly, the decrease in PNUE under SN was negatively related to the decrease in SLW. With a higher N_（area）, japonica rice cultivars did not show a higher A than indica rice cultivars because of possession of high-SLW leaves. Therefore, varietal difference in A was not related to N_（area）, and SLW can substantially interfere with the correlation between A and N_（area）. These findings may provide useful information for rice breeders to maximize A and PNUE, rather than over reliance on N_（area） as an indicator of photosynthetic performance.展开更多
A total of nine soybean （Glycine max （L.） Merr.） cultivars were divided into three yield levels which were planted under the same environmental condition. The net photosynthetic rate was measured by LI-6400 portab...A total of nine soybean （Glycine max （L.） Merr.） cultivars were divided into three yield levels which were planted under the same environmental condition. The net photosynthetic rate was measured by LI-6400 portable photosynthesis system. The chlorophyll content and specific leaf weight were measured with regular methods. The results showed that the specific leaf weight, chlorophyll content and net photosynthetic rate of high yield varieties were higher than those of low yield varieties. The yield had a significantly positive correlation with the net photosynthetic rate. With the improvement of modem technology, the net photosynthetic rate could be measured quickly and exactly. Hence, net photosynthetic rate could be used as an effective index in the selection of high yield soybean.展开更多
EDU reduces O_(3) sensitivity of alfalfa by mediating antioxidant enzyme activities.AM symbiosis increases stomatal conductance and plant O_(3) sensitivity.AM fungi increase stomatal conductance by increasing plant st...EDU reduces O_(3) sensitivity of alfalfa by mediating antioxidant enzyme activities.AM symbiosis increases stomatal conductance and plant O_(3) sensitivity.AM fungi increase stomatal conductance by increasing plant stomatal density.AM inoculation combined with EDU can mitigate negative effects of O_(3) on plants.Ozone(O_(3))is a phytotoxic air pollutant,both ethylenediurea(EDU)and arbuscular mycorrhizal(AM)fungi can affect plant O_(3) sensitivity.However,the underlying mechanisms of EDU and AM fungi on plant O_(3) sensitivity are unclear,and whether the combined application of the two can alleviate O_(3) damage has not been verified.In this study,an open-top chamber experiment was conducted to examine the effects of EDU and AM inoculation on growth and physiological parameters of alfalfa(Medicago sativa L.)plants under O_(3) enrichment.The results showed that EDU significantly decreased O_(3) visible injury(28.67%−68.47%),while AM inoculation significantly increased O_(3) visible injury.Mechanistically,the reduction of plant O_(3) sensitivity by EDU was mediated by antioxidant enzyme activities rather than stomatal conductance.Although AM inoculation increased antioxidant enzyme activities(4.99%−211.23%),it significantly increased stomatal conductance(42.69%)and decreased specific leaf weight(12.98%),the negative impact was overwhelming.Therefore,AM inoculation increased alfalfa’s O_(3) sensitivity.Furthermore,we found AM inoculation increased stomatal conductance by increasing stomatal density.The research indicated EDU was sufficient to counteract the negative effects of AM inoculation on O_(3) sensitivity.The combined application of EDU and AM fungi could largely alleviate the adverse effects of O_(3) on plant performance.展开更多
The aim of this work is to describe and compare three exploratory chemometrical tools,principal components analysis,independent components analysis and common components analysis,the last one being a modification of t...The aim of this work is to describe and compare three exploratory chemometrical tools,principal components analysis,independent components analysis and common components analysis,the last one being a modification of the multi-block statistical method known as common components and specific weights analysis.The three methods were applied to a set of data to show the differences and similarities of the results obtained,highlighting their complementarity.展开更多
Most apple orchards in the apple production districts in China were densely planted with vigorous rootstocks during the 1980 s. These orchards have suffered micro-environmental deterioration and loss of fruit quality ...Most apple orchards in the apple production districts in China were densely planted with vigorous rootstocks during the 1980 s. These orchards have suffered micro-environmental deterioration and loss of fruit quality because of the closed canopy. Modification of the denselyplanted orchards is a priority in current apple production. Intermediate thinning is a basic technique used to transform densely-planted apple orchards in China. Our goal was to provide theoretical basis for studying the effect of thinning on the efficiency of photosynthetically active radiation(PAR),fruit quality, and yield. We measured leaf area, solar radiation, and leaf air exchange at different tree canopy levels and by fitting relevant photosynthetic models, vertical distribution characteristics of leaf photosynthetic potentials and PAR were analyzed in various levels within canopies in densely-planted and intermediately-thinned orchards. Intermediate thinning significantly improved the radiant environment inside the canopies. PAR distribution within the canopies in the intermediately-thinned orchard was better distributed than in the densely-planted orchards. The invalid space under 30.0% of relative photosynthetically active radiation(PAR_r) was nearly zero in the intermediately-thinned orchard; but minimum PARr was 17.0% and the space under 0.30 of the relative height of the canopy was invalid for photosynthesis in the densely-planted orchard. The leaf photosynthetic efficiency in the intermediately-thinned orchard was improved. Photosynthetic rates(P_n) at the middle and bottom levels of the canopy, respectively, were increased by 7.80% and 10.20% in the intermediately-thinned orchard. Leaf development, which influences photosynthetic potential, was closely related to the surrounding micro-environment, especially light. Leaf photosynthetic potentials were correlated with leaf nitrogen content(N_1) and specific leaf weight(M_1) at various levels of canopies. Compared with the densely-planted orchard, the photosynthetic capacity parameters, such as maximum carboxylation rate(CE_(max)) and maximum electron transfer rate(J_(max)), significantly increased in the intermediately-thinned orchard. Leaf photosynthetic potentials mainly depended on Nl and Nl was closely related to PARr. Leaf photosynthetic potentials and PAR_r can be assessed using spatial distribution patterns of relative leaf nitrogen content(N_(lr)).展开更多
基金supported by the National Natural Science Foundation of China(31301840)the National Excellent Doctoral Dissertation of China(201465)+2 种基金the Program for Changjiang Scholars and Innovative Research Team in University of China(IRT1247)the Natural Science Foundation of Hubei Province,China(2013CFB201)the Fundamental Research Funds for the Central Universities,China(2013PY107)
文摘Increasing leaf photosynthesis per area（A） is of great importance to achieve yield further improvement. The aim of this study was to exploit varietal difference in A and its correlation with specific leaf weight（SLW）. Twelve rice cultivars, including 6 indica and 6 japonica varieties, were pot-grown under two N treatments, low N（LN） and sufficient N（SN）. Leaf photosynthesis and related parameters were measured at tillering stage. Compared with LN treatment, A, stomatal conductance（g_s）, mesophyll conductance（g_m）, leaf N content（N_（area））, and chlorophyll content were significantly improved under SN treatment, while SLW and photosynthetic N use efficiency（PNUE） were generally decreased. Varietal difference in A was positively related to both g_s and g_m, but not related to N_（area）. This resulted in a low PNUE in high N_（area） leaves. Varietal difference in PNUE was generally negatively related to SLW. Response of PNUE to N supply varied among different rice cultivars, and interestingly, the decrease in PNUE under SN was negatively related to the decrease in SLW. With a higher N_（area）, japonica rice cultivars did not show a higher A than indica rice cultivars because of possession of high-SLW leaves. Therefore, varietal difference in A was not related to N_（area）, and SLW can substantially interfere with the correlation between A and N_（area）. These findings may provide useful information for rice breeders to maximize A and PNUE, rather than over reliance on N_（area） as an indicator of photosynthetic performance.
基金Supported by the National Natural Science Foundation of China (30871547)Foundation of Department of Education of Jilin Province (2006041)Scientific Research Foundation of Jilin Agricultural University (2009028)
文摘A total of nine soybean （Glycine max （L.） Merr.） cultivars were divided into three yield levels which were planted under the same environmental condition. The net photosynthetic rate was measured by LI-6400 portable photosynthesis system. The chlorophyll content and specific leaf weight were measured with regular methods. The results showed that the specific leaf weight, chlorophyll content and net photosynthetic rate of high yield varieties were higher than those of low yield varieties. The yield had a significantly positive correlation with the net photosynthetic rate. With the improvement of modem technology, the net photosynthetic rate could be measured quickly and exactly. Hence, net photosynthetic rate could be used as an effective index in the selection of high yield soybean.
基金funded by the National Key Research and Development Program of China(Grant No.2017YFE0127700)the Key Research and Development Program of Shandong Province,China(Grant No.2021CXGC010803).
文摘EDU reduces O_(3) sensitivity of alfalfa by mediating antioxidant enzyme activities.AM symbiosis increases stomatal conductance and plant O_(3) sensitivity.AM fungi increase stomatal conductance by increasing plant stomatal density.AM inoculation combined with EDU can mitigate negative effects of O_(3) on plants.Ozone(O_(3))is a phytotoxic air pollutant,both ethylenediurea(EDU)and arbuscular mycorrhizal(AM)fungi can affect plant O_(3) sensitivity.However,the underlying mechanisms of EDU and AM fungi on plant O_(3) sensitivity are unclear,and whether the combined application of the two can alleviate O_(3) damage has not been verified.In this study,an open-top chamber experiment was conducted to examine the effects of EDU and AM inoculation on growth and physiological parameters of alfalfa(Medicago sativa L.)plants under O_(3) enrichment.The results showed that EDU significantly decreased O_(3) visible injury(28.67%−68.47%),while AM inoculation significantly increased O_(3) visible injury.Mechanistically,the reduction of plant O_(3) sensitivity by EDU was mediated by antioxidant enzyme activities rather than stomatal conductance.Although AM inoculation increased antioxidant enzyme activities(4.99%−211.23%),it significantly increased stomatal conductance(42.69%)and decreased specific leaf weight(12.98%),the negative impact was overwhelming.Therefore,AM inoculation increased alfalfa’s O_(3) sensitivity.Furthermore,we found AM inoculation increased stomatal conductance by increasing stomatal density.The research indicated EDU was sufficient to counteract the negative effects of AM inoculation on O_(3) sensitivity.The combined application of EDU and AM fungi could largely alleviate the adverse effects of O_(3) on plant performance.
文摘The aim of this work is to describe and compare three exploratory chemometrical tools,principal components analysis,independent components analysis and common components analysis,the last one being a modification of the multi-block statistical method known as common components and specific weights analysis.The three methods were applied to a set of data to show the differences and similarities of the results obtained,highlighting their complementarity.
基金supported by the National Modern Apple Technical System Program of the China Ministry of Agriculture(CARS-28)National Major Program of Research and Development Plan(2016YFD0201100)+1 种基金the‘12th Five-years Plan’National Science and Technology Support Project in Rural Areas(2011BAD32B03-02)the Natural Science Foundation Project of Shandong Province,P.R.China(ZR2009M015)
文摘Most apple orchards in the apple production districts in China were densely planted with vigorous rootstocks during the 1980 s. These orchards have suffered micro-environmental deterioration and loss of fruit quality because of the closed canopy. Modification of the denselyplanted orchards is a priority in current apple production. Intermediate thinning is a basic technique used to transform densely-planted apple orchards in China. Our goal was to provide theoretical basis for studying the effect of thinning on the efficiency of photosynthetically active radiation(PAR),fruit quality, and yield. We measured leaf area, solar radiation, and leaf air exchange at different tree canopy levels and by fitting relevant photosynthetic models, vertical distribution characteristics of leaf photosynthetic potentials and PAR were analyzed in various levels within canopies in densely-planted and intermediately-thinned orchards. Intermediate thinning significantly improved the radiant environment inside the canopies. PAR distribution within the canopies in the intermediately-thinned orchard was better distributed than in the densely-planted orchards. The invalid space under 30.0% of relative photosynthetically active radiation(PAR_r) was nearly zero in the intermediately-thinned orchard; but minimum PARr was 17.0% and the space under 0.30 of the relative height of the canopy was invalid for photosynthesis in the densely-planted orchard. The leaf photosynthetic efficiency in the intermediately-thinned orchard was improved. Photosynthetic rates(P_n) at the middle and bottom levels of the canopy, respectively, were increased by 7.80% and 10.20% in the intermediately-thinned orchard. Leaf development, which influences photosynthetic potential, was closely related to the surrounding micro-environment, especially light. Leaf photosynthetic potentials were correlated with leaf nitrogen content(N_1) and specific leaf weight(M_1) at various levels of canopies. Compared with the densely-planted orchard, the photosynthetic capacity parameters, such as maximum carboxylation rate(CE_(max)) and maximum electron transfer rate(J_(max)), significantly increased in the intermediately-thinned orchard. Leaf photosynthetic potentials mainly depended on Nl and Nl was closely related to PARr. Leaf photosynthetic potentials and PAR_r can be assessed using spatial distribution patterns of relative leaf nitrogen content(N_(lr)).
