Thirty genotypes from rice germplasm were identified under photooxidation and shading condition and divided into four basic types : (1) cultivars tolerant to both photooxidation and shading, (2) cultivars tolerant to...Thirty genotypes from rice germplasm were identified under photooxidation and shading condition and divided into four basic types : (1) cultivars tolerant to both photooxidation and shading, (2) cultivars tolerant to photooxidation but sensitive to shading, (3) cultivars tolerant to shading but sensitive to photooxidation, and (4) cultivars sensitive to photooxidation and shading. A comparative study of photosynthetic characteristics of a cultivar (cv. Wuyujing 3) that is tolerant and a cultivar (cv. Xiangxian) that is sensitive to both photoinhibition and shading showed that the photochemical efficiency of PSⅡ ( F v/F m ) and the content of PSⅡ_D1 protein in the tolerant cultivar “Wuyujing 3” decreased less under photoinhibition conditions as compared with “Xiangxian”. Under photooxidation conditions, superoxide dismutase was induced rapidly to a higher level and the active oxygen O - built up to a lower level in “Wuyujing 3” than in “Xiangxian”. At the same time, the photosynthetic rate decreased by 23% in “Wuyujing 3” vs. 64% in “Xiangxian”. Shading (20% natural light) during the booting stage caused only small decreases (7%-13%) in RuBisCO activity and the photosynthetic rate in “Wuyujing 3” but showed marked decreases (57%-64%) in “Xiangxian” which corresponded to the decreases in grain yield in the two cultivars (38% and 73%, respectively). The correlation analysis showed that the tolerance to photooxidation is mainly related to PSⅡ_D1 and that to shading is mainly related to RuBisCO activity. This study provided a simple and effective screening method and physiological basis for crop breeding in enhancing tolerance to both high and low radiation.展开更多
青藏联网工程正常运行期间,出现VCU(Valve Control Unit-阀控单元)光收发PS906异常,点火系统不能正常运行,PCP极控系统请求切换,导致换流阀不能正常导通,发生双极换相失败。在介绍青藏联网工程VCU的控制逻辑的基础上,详细分析了VCU故障...青藏联网工程正常运行期间,出现VCU(Valve Control Unit-阀控单元)光收发PS906异常,点火系统不能正常运行,PCP极控系统请求切换,导致换流阀不能正常导通,发生双极换相失败。在介绍青藏联网工程VCU的控制逻辑的基础上,详细分析了VCU故障导致换相失败的原因,并提出将相应设备接口环节双重化及PS900板卡A/B系统接入不同的PS912背板,避免阀组因单一的设备接口故障而引起直流系统故障,提高直流系统运行的抗干扰性和稳定性。展开更多
文摘Thirty genotypes from rice germplasm were identified under photooxidation and shading condition and divided into four basic types : (1) cultivars tolerant to both photooxidation and shading, (2) cultivars tolerant to photooxidation but sensitive to shading, (3) cultivars tolerant to shading but sensitive to photooxidation, and (4) cultivars sensitive to photooxidation and shading. A comparative study of photosynthetic characteristics of a cultivar (cv. Wuyujing 3) that is tolerant and a cultivar (cv. Xiangxian) that is sensitive to both photoinhibition and shading showed that the photochemical efficiency of PSⅡ ( F v/F m ) and the content of PSⅡ_D1 protein in the tolerant cultivar “Wuyujing 3” decreased less under photoinhibition conditions as compared with “Xiangxian”. Under photooxidation conditions, superoxide dismutase was induced rapidly to a higher level and the active oxygen O - built up to a lower level in “Wuyujing 3” than in “Xiangxian”. At the same time, the photosynthetic rate decreased by 23% in “Wuyujing 3” vs. 64% in “Xiangxian”. Shading (20% natural light) during the booting stage caused only small decreases (7%-13%) in RuBisCO activity and the photosynthetic rate in “Wuyujing 3” but showed marked decreases (57%-64%) in “Xiangxian” which corresponded to the decreases in grain yield in the two cultivars (38% and 73%, respectively). The correlation analysis showed that the tolerance to photooxidation is mainly related to PSⅡ_D1 and that to shading is mainly related to RuBisCO activity. This study provided a simple and effective screening method and physiological basis for crop breeding in enhancing tolerance to both high and low radiation.
文摘青藏联网工程正常运行期间,出现VCU(Valve Control Unit-阀控单元)光收发PS906异常,点火系统不能正常运行,PCP极控系统请求切换,导致换流阀不能正常导通,发生双极换相失败。在介绍青藏联网工程VCU的控制逻辑的基础上,详细分析了VCU故障导致换相失败的原因,并提出将相应设备接口环节双重化及PS900板卡A/B系统接入不同的PS912背板,避免阀组因单一的设备接口故障而引起直流系统故障,提高直流系统运行的抗干扰性和稳定性。
