镧浸种处理对玉米光合特性的影响

Effects of Lanthanum with Which Soaked Seeds on Photosynthetic Characteristics in Maize

为了探索镧对玉米光合特性的影响,采用露天盆栽方法,以氯化镧(LaCl3)溶液浸种处理玉米种子,测定大喇叭口期玉米叶片光合日变化、光响应曲线和CO2响应曲线及PEP羧化酶(PEPCase)活性。结果表明,高(120 mg.L-1)低(60 mg.L-1)两个La3+溶液浓度条件下,玉米叶片光合午休现象得到缓解,气孔因素是主要原因;La3+溶液浸种处理后,表观量子效率(AQY)和光饱和点(LSP)显著提高,羧化效率(CE)降低,La3+对PEPCase有明显的抑制作用。说明La3+溶液浸种预处理主要是通过提高植株对光能的利用来提高玉米叶片的光合效率。

Effects of lanthanum on photosynthetic characteristics in maize were studed which seeds soaked with LaCl3 solution of 60 mg·L-1 and 120 mg·L-1 concentrations and sowed in pots,the experiment in the open air,based on measurements of photosynthetic gas exchange parameters,diurnal variations of photo synthesis,light intensity-photosynthetic rate response curves,CO2 concentrations-photosynthetic rate response curves and PEPCase activities at spike formation stage by using CIRAS-Ⅱportable photosyntometer and spectrophotometer-meter,fitted the curve by the modified model of rectangular hyperbola,extraction of feature parameters.The results showed that the net photosynthetic rate（Pn） at midday were increased significantly and ＂midday depress＂ attributed mainly to stoma factor were relieved by treated seeds with 60 mg·L-1 solution.Under treatments of the seeds soaked with LaCl3 solution,the apparent quantum yield（AQY）,light saturation point（LSP） and the light compensation point（LCP） were improved significantly,but PEPCase activities,CO2 saturation point（CSP）,and carboxylation efficiency（CE） were decreased.It was suggested that effects of lanthanum with which soaked the seedes could increase photosynthetic efficiency in maize leaves which mainly attributed to improving the use of light energy,but the use of external CO2 were prejudiced,widespread use of rare earth in agriculture still has well prospects for development.