Crop water stress index(CWSI)is widely used for efficient irrigation management.Precise canopy temperature(T_(c))measurement is necessary to derive a reliable CWSI.The objective of this research was to investigate the...Crop water stress index(CWSI)is widely used for efficient irrigation management.Precise canopy temperature(T_(c))measurement is necessary to derive a reliable CWSI.The objective of this research was to investigate the influences of atmospheric conditions,settled height,view angle of infrared thermography,and investigating time of temperature measuring on the performance of the CWSI.Three irrigation treatments were used to create different soil water conditions during the 2020-2021 and 2021-2022 winter wheat-growing seasons.The CWSI was calculated using the CWSI-E(an empirical approach)and CWSI-T(a theoretical approach)based on the T_(c).Weather conditions were recorded continuously throughout the experimental period.The results showed that atmospheric conditions influenced the estimation of the CWSI;when the vapor pressure deficit(VPD)was>2000 Pa,the estimated CWSI was related to soil water conditions.The height of the installed infrared thermograph influenced the T_(c)values,and the differences among the T_(c)values measured at height of 3,5,and 10 m was smaller in the afternoon than in the morning.However,the lens of the thermometer facing south recorded a higher T_(c)than those facing east or north,especially at a low height,indicating that the direction of the thermometer had a significant influence on T_(c).There was a large variation in CWSI derived at different times of the day,and the midday measurements(12:00-15:00)were the most reliable for estimating CWSI.Negative linear relationships were found between the transpiration rate and CWSI-E(R^(2)of 0.3646-0.5725)and CWSI-T(R^(2)of 0.5407-0.7213).The relations between fraction of available soil water(FASW)with CWSI-T was higher than that with CWSI-E,indicating CWSI-T was more accurate for predicting crop water status.In addition,The R^(2)between CWSI-T and FASW at 14:00 was higher than that at other times,indicating that 14:00 was the optimal time for using the CWSI for crop water status monitoring.Relative higher yield of winter wheat was obtained with average seasonal values of CWSI-E and CWSI-T around 0.23 and 0.25-0.26,respectively.The CWSI-E values were more easily influenced by meteorological factors and the timing of the measurements,and using the theoretical approach to derive the CWSI was recommended for precise irrigation water management.展开更多
In order to determine the level of resistance of sugar beet varieties against Rhizoctonia solani AG 2-21IIB and AG 4, a methodology was implemented under greenhouse conditions that contemplated the most important crit...In order to determine the level of resistance of sugar beet varieties against Rhizoctonia solani AG 2-21IIB and AG 4, a methodology was implemented under greenhouse conditions that contemplated the most important criteria regarding to plant-pathogen interaction. The effect of plant growth stage on the development of the disease was evaluated. Seven sugar beet varieties were tested for resistance to R. solani AG 2-2IIIB and AG 4. To detect differences in leaf temperature between/L solani inoculated plants and non-infected plants, an infrared (IR) camera was tested. High incidence of R. solani AG 2-2IIIB and AG 4 in sugar beet plants was evident when the fungal inoculum was applied to two and four weeks old plants. At four weeks after sowing, it was the optimum time to inoculate sugar beet plants in order to generate R. solani infection, since at this time all plants were infected. Significant differences were detected regarding disease incidence between sugar beet varieties inoculated with different anastomosis groups. Leaf temperature was significant different between inoculated and non-inoculated plants, demonstrated that this technique could be a new tool for breeders to screen for resistance of new varieties.展开更多
Solid-state structure of the crystalline 1:1 complex [C3H10N(18-crown-6)]+[I3] (1) between 18-crown-6 and n-propylammonium triiodide has been determined at 293 and 93 K, respectively, showing a change from monoc...Solid-state structure of the crystalline 1:1 complex [C3H10N(18-crown-6)]+[I3] (1) between 18-crown-6 and n-propylammonium triiodide has been determined at 293 and 93 K, respectively, showing a change from monoclinic P21/m to monoclinic P21/a. Crystal structural analysis shows that in addition to van der Waals' forces, conventional N-H..-O hydrogen bonds are the key interactions. Measurements of unit cell parameters versus temperature show that the values of one of the three axes and the crystal volume change abruptly and remarkably at 220 K, indicating a first-order phase transition. The lack of the mirror plane in the low temperature structure is the most important differences between the two structural forms. Dif- ferential scanning calorimetry (DSC) measurement confirms that I undergoes a reversible phase transition at about 220 K with a thermal hysteresis of 3.5 K. The relatively large latent heat makes 1 a good candidate for phase change materials. The phase transition is accompanied by an anomaly of dielectric constant during heating and cooling process near the phase transition temperature.展开更多
基金supported by the Project of State Grid Hebei Electric Power Co.,Ltd.(SGHEYX00SCJS2100077).
文摘Crop water stress index(CWSI)is widely used for efficient irrigation management.Precise canopy temperature(T_(c))measurement is necessary to derive a reliable CWSI.The objective of this research was to investigate the influences of atmospheric conditions,settled height,view angle of infrared thermography,and investigating time of temperature measuring on the performance of the CWSI.Three irrigation treatments were used to create different soil water conditions during the 2020-2021 and 2021-2022 winter wheat-growing seasons.The CWSI was calculated using the CWSI-E(an empirical approach)and CWSI-T(a theoretical approach)based on the T_(c).Weather conditions were recorded continuously throughout the experimental period.The results showed that atmospheric conditions influenced the estimation of the CWSI;when the vapor pressure deficit(VPD)was>2000 Pa,the estimated CWSI was related to soil water conditions.The height of the installed infrared thermograph influenced the T_(c)values,and the differences among the T_(c)values measured at height of 3,5,and 10 m was smaller in the afternoon than in the morning.However,the lens of the thermometer facing south recorded a higher T_(c)than those facing east or north,especially at a low height,indicating that the direction of the thermometer had a significant influence on T_(c).There was a large variation in CWSI derived at different times of the day,and the midday measurements(12:00-15:00)were the most reliable for estimating CWSI.Negative linear relationships were found between the transpiration rate and CWSI-E(R^(2)of 0.3646-0.5725)and CWSI-T(R^(2)of 0.5407-0.7213).The relations between fraction of available soil water(FASW)with CWSI-T was higher than that with CWSI-E,indicating CWSI-T was more accurate for predicting crop water status.In addition,The R^(2)between CWSI-T and FASW at 14:00 was higher than that at other times,indicating that 14:00 was the optimal time for using the CWSI for crop water status monitoring.Relative higher yield of winter wheat was obtained with average seasonal values of CWSI-E and CWSI-T around 0.23 and 0.25-0.26,respectively.The CWSI-E values were more easily influenced by meteorological factors and the timing of the measurements,and using the theoretical approach to derive the CWSI was recommended for precise irrigation water management.
文摘In order to determine the level of resistance of sugar beet varieties against Rhizoctonia solani AG 2-21IIB and AG 4, a methodology was implemented under greenhouse conditions that contemplated the most important criteria regarding to plant-pathogen interaction. The effect of plant growth stage on the development of the disease was evaluated. Seven sugar beet varieties were tested for resistance to R. solani AG 2-2IIIB and AG 4. To detect differences in leaf temperature between/L solani inoculated plants and non-infected plants, an infrared (IR) camera was tested. High incidence of R. solani AG 2-2IIIB and AG 4 in sugar beet plants was evident when the fungal inoculum was applied to two and four weeks old plants. At four weeks after sowing, it was the optimum time to inoculate sugar beet plants in order to generate R. solani infection, since at this time all plants were infected. Significant differences were detected regarding disease incidence between sugar beet varieties inoculated with different anastomosis groups. Leaf temperature was significant different between inoculated and non-inoculated plants, demonstrated that this technique could be a new tool for breeders to screen for resistance of new varieties.
基金supported by the National Natural Science Foundation of China (20701007 & 90922005)Natural Science Foundation of Jiangsu Province (BK2008286 & BK2008029)
文摘Solid-state structure of the crystalline 1:1 complex [C3H10N(18-crown-6)]+[I3] (1) between 18-crown-6 and n-propylammonium triiodide has been determined at 293 and 93 K, respectively, showing a change from monoclinic P21/m to monoclinic P21/a. Crystal structural analysis shows that in addition to van der Waals' forces, conventional N-H..-O hydrogen bonds are the key interactions. Measurements of unit cell parameters versus temperature show that the values of one of the three axes and the crystal volume change abruptly and remarkably at 220 K, indicating a first-order phase transition. The lack of the mirror plane in the low temperature structure is the most important differences between the two structural forms. Dif- ferential scanning calorimetry (DSC) measurement confirms that I undergoes a reversible phase transition at about 220 K with a thermal hysteresis of 3.5 K. The relatively large latent heat makes 1 a good candidate for phase change materials. The phase transition is accompanied by an anomaly of dielectric constant during heating and cooling process near the phase transition temperature.