表油菜素内酯对冬小麦开花后光合特性和物质生产的影响

Effect of epibrassinolide on photosynthetic performance and dry matter production after anthesis of winter wheat

为明确表油菜素内酯对小麦生育后期光合特性的影响和最适应用时期和浓度,以冬小麦品种‘石麦18’为材料,设置起身期、起身期＋孕穗期、孕穗期3个喷施时期为主区,0~0.15mg/L 4个表油菜素内酯喷施浓度（每次喷施量673.8kg/hm2）为副区的裂区试验,测定了开花后旗叶的净光合速率（Pn）、气孔导度（Gs）、胞间CO2浓度（Ci）、蒸腾速率（Tr）、叶绿素SPAD值,以及成熟期植株和籽粒干物质量。结果表明：各处理小麦旗叶的Pn、Gs、Ci、Tr和叶绿素SPAD值从开花期开始均逐渐提高,叶绿素SPAD值开花后10d达到最高值,Pn等4项光合参数在开花后15d达到最高值,然后开始下降。不同处理比较,起身期1次喷施、起身期＋孕穗期2次喷施的,4种浓度之间光合参数、叶绿素SPAD值在各测定日期基本上都是0.1mg/L〉0.05mg/L〉0.15mg/L〉对照,且0.1mg/L与其他浓度的差异显著;孕穗期喷施的则是0.05mg/L〉0.1mg/L〉0.15mg/L〉对照,且0.05mg/L与其他浓度的差异显著。各测定日期的光合作用参数和叶绿素SPAD值均以起身期＋孕穗期2次喷施0.1mg/L的最高。处理之间光合作用参数的差异,比处理之间叶绿素SPAD值的差异更大。各处理之间总干物质和籽粒干物质量的差异,与光合参数和叶绿素SPAD值的差异一致。表油菜素内酯喷施浓度对干物质量的影响大于喷施时期的影响,对总干物质量的影响大于对籽粒干物质量的影响。综合以上结果,应用表油菜素内酯调控小麦光合性能和物质生产,以起身期＋孕穗期2次各喷施0.1 mg/L水溶液670kg/hm2左右为宜。如喷施1次,起身期以0.1mg/L、孕穗期以0.05mg/L为宜。

In order to clarify the effect of epibrassinolide on the photosynthetic performance during late growing period of wheat ,and the proper application stage and concentration ,with a winter wheat cultivar ‘Shimai 18’ as materials ,a field experiment designed as spilt plots , with three foliar spraying stage combinations ,i .e .erecting stage ,erecting ＋ booting stage , booting stage ,as main plots ,and four spraying concentrations of epibrassinolide ,0 ,0 .05 ,0 . 1 and 0 .15 mg/L （673 .8 kg/hm2 water solution for each spraying ） as split plots ,was conduc‐ted .Net photosynthetic rate （Pn） ,stomatal conductivity （Gs） ,intercellular CO2 concentra‐tion （Ci） ,transpiration rate （ Tr） ,chlorophyll SPAD of flag leaves after anthesis ,and the dry mass of wheat plants and grains at maturity were determined .The main results showed that ,Pn ,Gs ,Ci , Tr and chlorophyll SPAD of flag leaves increased gradually since anthesis , and reached maximum 10 days after anthesis for SPAD ,but 15 days for the four photosyn‐thetic parameters ,Pn ,Gs ,Ci and Tr ,then decreased .Comparison among all the treatments showed that ,all the photosynthetic parameters and SPAD during the determination period were in the order 0 .1 mg/L〉0 .05 mg/L〉0 .15 mg/L〉0 mg/L （CK） in the main plots with once spraying at erecting stage and twice spraying at erecting ＋ booting stage ,and the differ‐ences between the parameters of 0 .1 mg/L and those of other concentrations were statistically significant （P〈0 .05） .In the main plot with once spraying at booting stage ,however ,the values of the parameters were in the order 0 .05 mg/L 〉 0 .1 mg/L 〉 0 .15 mg/L 〉 0 mg/L （CK） ,and the parameters of 0 .05 mg/L were significantly higher than those of other concen‐trations .All the photosynthetic parameters and SPAD of the treatment twice spraying 0 .1 mg/L at erecting ＋ booting stage were the highest in all treatments during the determination period .The differences of photosynthetic parameters among treatments were more significant than those of chlorophyll SPAD among treatments . T he differences of dry mass of w heat plants and grains among treatments were similar to those of photosynthetic parameters and chlorophyll SPAD .The effect of epibrassinolide spraying concentration on dry mass was grea‐ter than that of spraying stage ,and the effect on dry mass of wheat plants was greater than that on dry mass of w heat grains .According to the results ,for the purpose of regulating pho‐tosynthetic performance and dry matter production ,it is recommended to spray water solution of epibrassinolide with a concentration of 0 .1 mg/L two times at erecting and booting stage （about 670 kg/hm2 each time） .If spraying once ,however ,the concentration 0 .1 mg/L at e‐recting stage ,or 0 .05 mg/L at booting stage ,is recommended .