在盆栽试验条件下，研究在3个遮阴水平和5个施氮水平处理组合下，水稻分蘖期、孕穗期和抽穗期冠层叶片叶绿素计测定值（soil and plant analyzer development value，SPAD value）的空间分布规律及其差异，为弱光条件下实时进行水稻叶...在盆栽试验条件下，研究在3个遮阴水平和5个施氮水平处理组合下，水稻分蘖期、孕穗期和抽穗期冠层叶片叶绿素计测定值（soil and plant analyzer development value，SPAD value）的空间分布规律及其差异，为弱光条件下实时进行水稻叶片氮素营养诊断及优化提供依据.结果表明，同对照相比，在遮阴条件下水稻冠层 SPAD值波动幅度受到明显抑制.遮光使水稻冠层叶片 SPAD值下降，并抑制施氮水平对水稻叶片向上位叶输送氮素的正向作用.经变异系数分析发现，L4叶对施氮水平变化反应最为敏感.另外，在中度和重度遮阴条件（遮光率分别为65%和85%）下可利用叶片相对叶色差值（relative SPAD value，RSPAD）进行氮素营养状态的诊断.相对叶色差值SPADL3-L2，SPADL4-L3与施氮水平呈显著线性正相关关系（R2L3-L2=0.87~0.97，R2L4-L3=0.85~0.97），这一关系不受生育期和施氮水平的影响.在正常光照条件下，宜选用 SPADL3-L2指示水稻整个生育期氮素营养状况.在日照较弱的季节或受林木遮光影响较大的田块，宜选择 SPADL4-L3作为诊断指标.展开更多
以不同温度胁迫下(35℃/3d、35℃/5d、38℃/3d和38℃/5d)的水稻田间试验为基础,研究抽穗期高温胁迫对两个水稻品种扬稻6号和南粳43的干物质积累和分配、叶片绿色度值(Soil and plant analyzer development,SPAD)和净光合速率的影响。结...以不同温度胁迫下(35℃/3d、35℃/5d、38℃/3d和38℃/5d)的水稻田间试验为基础,研究抽穗期高温胁迫对两个水稻品种扬稻6号和南粳43的干物质积累和分配、叶片绿色度值(Soil and plant analyzer development,SPAD)和净光合速率的影响。结果表明,与常温对照(CK)相比,高温胁迫下,两个水稻品种干物质积累量、SPAD值和净光合速率显著下降(P<0.05),茎鞘物质输出率和转运率显著增加(P<0.05)。随着胁迫温度的升高和胁迫时间的延长,两个水稻品种各指标的变化幅度逐渐增加。不同水稻品种对高温胁迫的反应不同,扬稻6号受高温影响要小于南粳43。展开更多
通过两年的田间试验,利用叶绿素仪(SPAD-502)测定了不同生育时期水稻(南粳44号)冠层叶片的SPAD(soilplant analysed and development)值、叶绿素含量、叶氮含量及净光合速率,在此基础上分析了SPAD值与叶绿素含量、叶氮含量及净光合速率...通过两年的田间试验,利用叶绿素仪(SPAD-502)测定了不同生育时期水稻(南粳44号)冠层叶片的SPAD(soilplant analysed and development)值、叶绿素含量、叶氮含量及净光合速率,在此基础上分析了SPAD值与叶绿素含量、叶氮含量及净光合速率的关系。结果表明:水稻冠层叶片的SPAD值与叶绿素含量、叶氮含量及净光合速率的关系均呈显著相关,但是在不同的生育期内SPAD值与其他三项指标的变化并没有同步,存在一定时间的超前或者滞后。随着叶绿素荧光分析技术的发展,无损伤、快速、灵敏测定叶片光合作用的变化成为可能,因此想要更好地了解叶片光合作用的内在变化,还需要研究SPAD值与各项叶绿素荧光参数的关系。展开更多
Precise estimation of vegetable nitrogen(N)status is critical in optimizing N fertilization management.However,nondestructive and accurate N diagnostic methods for vegetables are relatively scarce.In our two-year fiel...Precise estimation of vegetable nitrogen(N)status is critical in optimizing N fertilization management.However,nondestructive and accurate N diagnostic methods for vegetables are relatively scarce.In our two-year field experiment,we evaluated whether an active canopy sensor(GreenSeeker)could be used to nondestructively predict N status of bok choy(Brassica rapa subsp.chinensis)compared with a chlorophyll meter.Results showed that the normalized difference vegetation index(NDVI)and ratio vegetation index(RVI)generated by the active canopy sensor were well correlated with the aboveground biomass(AGB)(r=0.698–0.967),plant N uptake(PNU)(r=0.642–0.951),and root to shoot ratio(RTS)(r=-0.426 to-0.845).Compared with the chlorophyll meter,the active canopy sensor displayed much higher accuracy(5.0%–177.4%higher)in predicting AGB and PNU and equal or slightly worse(0.54–1.82 times that of the chlorophyll meter)for RTS.The sensor-based NDVI model performed equally well in estimating AGB(R2=0.63)and PNU(R2=0.61),but the meter-based model predicted RTS better(R2=0.50).Inclusion of the days after transplanting(DAT)significantly improved the accuracy of sensor-based AGB(19.0%–56.7%higher)and PNU(24.6%–84.6%higher)estimation models.These findings suggest that the active canopy sensor has a great potential for nondestructively estimating N status of bok choy accurately and thus for better N recommendations,especially with inclusion of DAT,and could be applied to more vegetables with some verification.展开更多
文摘以不同温度胁迫下(35℃/3d、35℃/5d、38℃/3d和38℃/5d)的水稻田间试验为基础,研究抽穗期高温胁迫对两个水稻品种扬稻6号和南粳43的干物质积累和分配、叶片绿色度值(Soil and plant analyzer development,SPAD)和净光合速率的影响。结果表明,与常温对照(CK)相比,高温胁迫下,两个水稻品种干物质积累量、SPAD值和净光合速率显著下降(P<0.05),茎鞘物质输出率和转运率显著增加(P<0.05)。随着胁迫温度的升高和胁迫时间的延长,两个水稻品种各指标的变化幅度逐渐增加。不同水稻品种对高温胁迫的反应不同,扬稻6号受高温影响要小于南粳43。
文摘通过两年的田间试验,利用叶绿素仪(SPAD-502)测定了不同生育时期水稻(南粳44号)冠层叶片的SPAD(soilplant analysed and development)值、叶绿素含量、叶氮含量及净光合速率,在此基础上分析了SPAD值与叶绿素含量、叶氮含量及净光合速率的关系。结果表明:水稻冠层叶片的SPAD值与叶绿素含量、叶氮含量及净光合速率的关系均呈显著相关,但是在不同的生育期内SPAD值与其他三项指标的变化并没有同步,存在一定时间的超前或者滞后。随着叶绿素荧光分析技术的发展,无损伤、快速、灵敏测定叶片光合作用的变化成为可能,因此想要更好地了解叶片光合作用的内在变化,还需要研究SPAD值与各项叶绿素荧光参数的关系。
基金supported by the National Key Research and Development Program of China(No.2016YFD0201001)the National Natural Science Foundation of China(No.31672236)
文摘Precise estimation of vegetable nitrogen(N)status is critical in optimizing N fertilization management.However,nondestructive and accurate N diagnostic methods for vegetables are relatively scarce.In our two-year field experiment,we evaluated whether an active canopy sensor(GreenSeeker)could be used to nondestructively predict N status of bok choy(Brassica rapa subsp.chinensis)compared with a chlorophyll meter.Results showed that the normalized difference vegetation index(NDVI)and ratio vegetation index(RVI)generated by the active canopy sensor were well correlated with the aboveground biomass(AGB)(r=0.698–0.967),plant N uptake(PNU)(r=0.642–0.951),and root to shoot ratio(RTS)(r=-0.426 to-0.845).Compared with the chlorophyll meter,the active canopy sensor displayed much higher accuracy(5.0%–177.4%higher)in predicting AGB and PNU and equal or slightly worse(0.54–1.82 times that of the chlorophyll meter)for RTS.The sensor-based NDVI model performed equally well in estimating AGB(R2=0.63)and PNU(R2=0.61),but the meter-based model predicted RTS better(R2=0.50).Inclusion of the days after transplanting(DAT)significantly improved the accuracy of sensor-based AGB(19.0%–56.7%higher)and PNU(24.6%–84.6%higher)estimation models.These findings suggest that the active canopy sensor has a great potential for nondestructively estimating N status of bok choy accurately and thus for better N recommendations,especially with inclusion of DAT,and could be applied to more vegetables with some verification.
