Despite an increase in spectrum of industrial applications of yttrium （Y） and the fact that it is widely present in the soils and plants, some of which are agronomically important crops, its effects on plant growth ...Despite an increase in spectrum of industrial applications of yttrium （Y） and the fact that it is widely present in the soils and plants, some of which are agronomically important crops, its effects on plant growth and metabolism are still obscure. Therefore, the aim of this work was to examine the effect of different concentrations of Y on its accumulation and distribution, photosynthetic responses, water relations, free proline concentration and growth of young maize plants. The experiment was done with maize （Zea mays L., hybrid NS-640）, in water cultures, under semi-controlled conditions of a greenhouse. Plants were supplied with half-strength complete Hoagland nutrient solution, to which was added either 0 （control）, 10-5, 10-4 or 10-3 mol/L Y, in the form of Y（NO）3·5H2O. Each variant was set in thirteen replications, with six plants in each replication. Plants were grown for 21 d and they were at the stage of 3 and 4 leaves when they were analyzed. The presence of Y reduced maize growth and photosynthetic performance. Dimensions of stomata significantly decreased while their density significantly increased on both adaxial and abaxial epidermis. Plant height, root length, total leaf area and dry mass also declined. Concentration of photosynthetic pigments （chl a and b and carotenoids） and free proline decreased. Photosynthesis and transpiration were impaired in the presence of Y-their intensities were also reduced, and the same stands for stomatal conductance of water vapor, photosynthetic water use efficiency （WUE） and water content. Although the highest concentration of Y was found in maize roots in each treatment, Y concentration in the second leaf and shoot also significantly increased with an increase in Y concentration in the nutrient solution. Albeit Y concentration was much higher in roots than in shoots, shoot metabolism and growth were much more disrupted. The results demonstrated that young maize plants accumulated significant amount of Y and that this element, when present in higher concentrations, had unfavorable effect on physiological processes and therefore plant growth.展开更多
Overuse of irrigation water to ensure the crop yield of maize plants has caused serious water shortage problems in the middle reach of Heihe River, China. Thus, further research on the physiological characteristics, i...Overuse of irrigation water to ensure the crop yield of maize plants has caused serious water shortage problems in the middle reach of Heihe River, China. Thus, further research on the physiological characteristics, i.e., photosynthetic rate and leaf transpiration rate, are urgently needed to develop an efficient irrigation management system. In this paper, we selected two common soil textures （sandy loam, sand） and three one-time irrigation volumes （60 mm, 20 mm, 0 mm） in order to analyze the impact of soil conditions on the physiological characteristics of maize plants. Physiological and meteorological factors, soil water content and plant growing parameters were synchronously monitored on Jun. 30, Jul. 25 and Aug. 27 of 2012. The results indicate that sandy loam is better than sand for the growth of maize plants and single irrigation may provide limited influence on the physiological characteristics. Thus, increasing irrigation times and decreasing one-time volume is suggested for an efficient irrigation system.展开更多
In a long term study photosynthetically active radiation was monitored for three rainy seasons to measure the effects of hedgerow intercropping in rotation with maize and cowpea in a senna/siamea and panicum/grass str...In a long term study photosynthetically active radiation was monitored for three rainy seasons to measure the effects of hedgerow intercropping in rotation with maize and cowpea in a senna/siamea and panicum/grass strip on biomass yield and light use efficiency. Maize/cowpea intercropped with senna siamea or grass stripped were compared with sole maize and cowpea. A ceptometer was applied to measure PAR interception by sole maize or cowpea or crop/tree and grass/crop interfaces and separation of PAR used by each plant or tree/grass component. Hedgerow intercropping increased PAR interception and biomass formation. C4 plants had higher LUE than C3 plants while combining C4 and C3 in the agroforestry system lowered LUE. The tree/crop interfaces increased PAR interception than at 1 m and 2 m away from the hedgerow. The row of maize or cowpea at lm intercepted more PAR than the row at 2 m from hedgerow while the cowpea row next to the hedgerow was depressed compared to the rows in the middle rows which had higher yields. The maize or cowpea row next to the grass strip was more stressed than the rows in the middle of the alley.展开更多
Maize is one of the most important crops cultivated on the global scale.Accurate estimation of maize Gross Primary Production(GPP)can provide valuable information for regional and global carbon budget studies.From sit...Maize is one of the most important crops cultivated on the global scale.Accurate estimation of maize Gross Primary Production(GPP)can provide valuable information for regional and global carbon budget studies.From site level to regional/global scales,GPP estimation depends on remote sensing or eddy covariance flux data.In this research,the 8-day composite GPP of maize was estimated by Moderate Resolution Imaging Spectroradiometer(MODIS)and flux tower data at eight study sites using a Regional Production Efficiency Model(REG-PEM).The performance of the model was assessed by analyzing the linearly regression of GPP estimated from the REG-PEM model(GPPEST)with the GPP predicted from the eddy covariance data(GPPEC).The coefficient of determination,root mean squared error and mean absolute error of the regression model were calculated.The uncertainties of the model are also discussed in this research.The seasonal dynamics(phases and magnitudes)of the GPPEST reasonably agreed with those of GPPEC,indicating the potential of the satellite-driven REG-PEM model for up-scaling the GPP in maize croplands.Furthermore,the maize GPP estimated by this model is more accurate than the MODIS GPP products(MOD17A2).In particular,MOD17A2 significantly underestimated the GPP of maize croplands.The uncertainties in the REG-PEM model are mostly contributed by the maximum light use efficiency and the fraction of photosynthetically active radiation.展开更多
Ulmus crassifolia Nutt. (Cedar elm, Ulmaceae) is a tree found in central and east Texas, northern Mexico, east to Florida, and north to southern Missouri and Oklahoma. Ungnadia speciosa Endl. (Mexican-buckeye, Sapinda...Ulmus crassifolia Nutt. (Cedar elm, Ulmaceae) is a tree found in central and east Texas, northern Mexico, east to Florida, and north to southern Missouri and Oklahoma. Ungnadia speciosa Endl. (Mexican-buckeye, Sapindaceae) is a shrub or small tree found in woodlands and savannas of central and western Texas, southern New Mexico and northern Mexico. In central Texas, both species are found in Juniperus ashei/Quercus virginiana woodlands or savannas or also at low density in inter-canopy grassland gaps or patches. Environmental conditions in this area are stressful because of shallow soils, high summer temperatures, and inconsistent low rainfall. Currently, both species have a low density in these areas, and Ulmus crassifolia is usually a tree, while Ungnadia speciosa is a woody understory shrub. This study suggests U. crassifolia and U. speciosa are tolerant or intermediate species, with juveniles starting in shade. Maximum photosynthetic rate (A<sub>max</sub>), dark respiration (R<sub>d</sub>), intercellular CO<sub>2</sub>, light saturation (L<sub>sp</sub>) and water use efficiency significantly increased when light levels and CO<sub>2</sub> concentrations were elevated for both species, but not when temperatures were elevated. Stomatal conductance decreased when the CO<sub>2</sub> concentration doubled, but there were few effects from elevated temperature. These findings suggest that U. speciosa and U. crassifolia should be more common and imply that they will have a higher density in a future high CO<sub>2</sub> environment.展开更多
Previous studies showed that Chaetomium globosum ND35 fungus fertilizer can improve the microbial community structure and enzyme activities of replanted soil. However, it remains unclear whether can improve the physio...Previous studies showed that Chaetomium globosum ND35 fungus fertilizer can improve the microbial community structure and enzyme activities of replanted soil. However, it remains unclear whether can improve the physiological and ecological characteristics of plants under successive rotation. In this study, we investigated the photosynthetic, physiological, and biochemical indexes including photosynthetic parameters, chlorophyll fluorescence, and chlorophyll content of 1-yeax-old poplar seedlings under seven different doses （range from 0 to 1.67 g kg-1） of C. globosum ND35 fungus fertilizer to study the effects of fungus fertilizer on photosynthesis of Poplar. Our results showed that： （1） With increasing application of fungus fertilizer in replanted soil, chlorophyll content of poplar leaves （Chl） increased, while physiological indexes such as electron transport rate （ETR）, net photosynthetic rate （Pn）, quantum efficiency （φ）, nitrate reductase （NR） activity and root vigor initially increased and then declined. Meanwhile, heat dissipation that depended on the xanthophyll cycle declined and nonphotochemical quenching （NPQ） initially increased and then decreased. When the dose of C. globosum ND35 fungus fertilizer was 0.67 g kg-1 （T3） and 1.00 g kg-1 （T4）, excess light energy of photosynthetic apparatus was reduced, and photosynthetic apparatus distributed more light energy to the direction of photochemical reactions, which improved the efficiency of energy use. Plant height and biomass of leaves, stems, and roots were maximum at T3. We conclude that applying appropriate amounts of C. globosum ND35 fungus fertilizer can improve root physiological activity and capacity for use of light by poplar leaves. This can improve the operating states of the photosynthetic apparatus and lead to increased photosynthetic efficiency of poplar leaves and accumulation of dry matter.This suggests a strategy to alleviate the successive rotation obstacle of soil nutrient depletion.展开更多
基金Project supported by Ministry of Education,Science and Technological Development of the Republic of Serbia
文摘Despite an increase in spectrum of industrial applications of yttrium （Y） and the fact that it is widely present in the soils and plants, some of which are agronomically important crops, its effects on plant growth and metabolism are still obscure. Therefore, the aim of this work was to examine the effect of different concentrations of Y on its accumulation and distribution, photosynthetic responses, water relations, free proline concentration and growth of young maize plants. The experiment was done with maize （Zea mays L., hybrid NS-640）, in water cultures, under semi-controlled conditions of a greenhouse. Plants were supplied with half-strength complete Hoagland nutrient solution, to which was added either 0 （control）, 10-5, 10-4 or 10-3 mol/L Y, in the form of Y（NO）3·5H2O. Each variant was set in thirteen replications, with six plants in each replication. Plants were grown for 21 d and they were at the stage of 3 and 4 leaves when they were analyzed. The presence of Y reduced maize growth and photosynthetic performance. Dimensions of stomata significantly decreased while their density significantly increased on both adaxial and abaxial epidermis. Plant height, root length, total leaf area and dry mass also declined. Concentration of photosynthetic pigments （chl a and b and carotenoids） and free proline decreased. Photosynthesis and transpiration were impaired in the presence of Y-their intensities were also reduced, and the same stands for stomatal conductance of water vapor, photosynthetic water use efficiency （WUE） and water content. Although the highest concentration of Y was found in maize roots in each treatment, Y concentration in the second leaf and shoot also significantly increased with an increase in Y concentration in the nutrient solution. Albeit Y concentration was much higher in roots than in shoots, shoot metabolism and growth were much more disrupted. The results demonstrated that young maize plants accumulated significant amount of Y and that this element, when present in higher concentrations, had unfavorable effect on physiological processes and therefore plant growth.
基金supported by the China Postdoctoral Science Foundation (Grant No. 2015M572622)the National Natural Science Foundation of China (Grant No. 41501044)
文摘Overuse of irrigation water to ensure the crop yield of maize plants has caused serious water shortage problems in the middle reach of Heihe River, China. Thus, further research on the physiological characteristics, i.e., photosynthetic rate and leaf transpiration rate, are urgently needed to develop an efficient irrigation management system. In this paper, we selected two common soil textures （sandy loam, sand） and three one-time irrigation volumes （60 mm, 20 mm, 0 mm） in order to analyze the impact of soil conditions on the physiological characteristics of maize plants. Physiological and meteorological factors, soil water content and plant growing parameters were synchronously monitored on Jun. 30, Jul. 25 and Aug. 27 of 2012. The results indicate that sandy loam is better than sand for the growth of maize plants and single irrigation may provide limited influence on the physiological characteristics. Thus, increasing irrigation times and decreasing one-time volume is suggested for an efficient irrigation system.
文摘In a long term study photosynthetically active radiation was monitored for three rainy seasons to measure the effects of hedgerow intercropping in rotation with maize and cowpea in a senna/siamea and panicum/grass strip on biomass yield and light use efficiency. Maize/cowpea intercropped with senna siamea or grass stripped were compared with sole maize and cowpea. A ceptometer was applied to measure PAR interception by sole maize or cowpea or crop/tree and grass/crop interfaces and separation of PAR used by each plant or tree/grass component. Hedgerow intercropping increased PAR interception and biomass formation. C4 plants had higher LUE than C3 plants while combining C4 and C3 in the agroforestry system lowered LUE. The tree/crop interfaces increased PAR interception than at 1 m and 2 m away from the hedgerow. The row of maize or cowpea at lm intercepted more PAR than the row at 2 m from hedgerow while the cowpea row next to the hedgerow was depressed compared to the rows in the middle rows which had higher yields. The maize or cowpea row next to the grass strip was more stressed than the rows in the middle of the alley.
基金China’s Special Funds for Major State Basic Research Project(2013CB733405)the National Natural Science Foundation of China(41471294)+1 种基金the open fund of the State Key Laboratory of Remote Sensing Science(OFSLRSS201408)China Scholarship Council,and OATF from UESTC.
文摘Maize is one of the most important crops cultivated on the global scale.Accurate estimation of maize Gross Primary Production(GPP)can provide valuable information for regional and global carbon budget studies.From site level to regional/global scales,GPP estimation depends on remote sensing or eddy covariance flux data.In this research,the 8-day composite GPP of maize was estimated by Moderate Resolution Imaging Spectroradiometer(MODIS)and flux tower data at eight study sites using a Regional Production Efficiency Model(REG-PEM).The performance of the model was assessed by analyzing the linearly regression of GPP estimated from the REG-PEM model(GPPEST)with the GPP predicted from the eddy covariance data(GPPEC).The coefficient of determination,root mean squared error and mean absolute error of the regression model were calculated.The uncertainties of the model are also discussed in this research.The seasonal dynamics(phases and magnitudes)of the GPPEST reasonably agreed with those of GPPEC,indicating the potential of the satellite-driven REG-PEM model for up-scaling the GPP in maize croplands.Furthermore,the maize GPP estimated by this model is more accurate than the MODIS GPP products(MOD17A2).In particular,MOD17A2 significantly underestimated the GPP of maize croplands.The uncertainties in the REG-PEM model are mostly contributed by the maximum light use efficiency and the fraction of photosynthetically active radiation.
文摘Ulmus crassifolia Nutt. (Cedar elm, Ulmaceae) is a tree found in central and east Texas, northern Mexico, east to Florida, and north to southern Missouri and Oklahoma. Ungnadia speciosa Endl. (Mexican-buckeye, Sapindaceae) is a shrub or small tree found in woodlands and savannas of central and western Texas, southern New Mexico and northern Mexico. In central Texas, both species are found in Juniperus ashei/Quercus virginiana woodlands or savannas or also at low density in inter-canopy grassland gaps or patches. Environmental conditions in this area are stressful because of shallow soils, high summer temperatures, and inconsistent low rainfall. Currently, both species have a low density in these areas, and Ulmus crassifolia is usually a tree, while Ungnadia speciosa is a woody understory shrub. This study suggests U. crassifolia and U. speciosa are tolerant or intermediate species, with juveniles starting in shade. Maximum photosynthetic rate (A<sub>max</sub>), dark respiration (R<sub>d</sub>), intercellular CO<sub>2</sub>, light saturation (L<sub>sp</sub>) and water use efficiency significantly increased when light levels and CO<sub>2</sub> concentrations were elevated for both species, but not when temperatures were elevated. Stomatal conductance decreased when the CO<sub>2</sub> concentration doubled, but there were few effects from elevated temperature. These findings suggest that U. speciosa and U. crassifolia should be more common and imply that they will have a higher density in a future high CO<sub>2</sub> environment.
基金supported by the China“973”projects(No.2012CB416904)the National Natural Science Foundation of China(Nos.31770706,31370702,31500511)+1 种基金the research and demonstration on the key technology of vegetation restoration and reconstruction in the open pit of in eastern Shandong hilly area(201504406)the Key Project of Natural Science Foundation of Shandong Province,China(Nos.ZR2015JL014,ZR2015CL044)
文摘Previous studies showed that Chaetomium globosum ND35 fungus fertilizer can improve the microbial community structure and enzyme activities of replanted soil. However, it remains unclear whether can improve the physiological and ecological characteristics of plants under successive rotation. In this study, we investigated the photosynthetic, physiological, and biochemical indexes including photosynthetic parameters, chlorophyll fluorescence, and chlorophyll content of 1-yeax-old poplar seedlings under seven different doses （range from 0 to 1.67 g kg-1） of C. globosum ND35 fungus fertilizer to study the effects of fungus fertilizer on photosynthesis of Poplar. Our results showed that： （1） With increasing application of fungus fertilizer in replanted soil, chlorophyll content of poplar leaves （Chl） increased, while physiological indexes such as electron transport rate （ETR）, net photosynthetic rate （Pn）, quantum efficiency （φ）, nitrate reductase （NR） activity and root vigor initially increased and then declined. Meanwhile, heat dissipation that depended on the xanthophyll cycle declined and nonphotochemical quenching （NPQ） initially increased and then decreased. When the dose of C. globosum ND35 fungus fertilizer was 0.67 g kg-1 （T3） and 1.00 g kg-1 （T4）, excess light energy of photosynthetic apparatus was reduced, and photosynthetic apparatus distributed more light energy to the direction of photochemical reactions, which improved the efficiency of energy use. Plant height and biomass of leaves, stems, and roots were maximum at T3. We conclude that applying appropriate amounts of C. globosum ND35 fungus fertilizer can improve root physiological activity and capacity for use of light by poplar leaves. This can improve the operating states of the photosynthetic apparatus and lead to increased photosynthetic efficiency of poplar leaves and accumulation of dry matter.This suggests a strategy to alleviate the successive rotation obstacle of soil nutrient depletion.
