小麦茎顶端原基分化的动态模式与特征研究

Studies on Dynamic Models and Characteristics of Apex Primordium Differentiation in Wheat

小麦各类茎顶端原基分化与播种后累积生长度日 ( GDD)之间均呈 S曲线关系 ,符合 L ogistic数学模型 ,表明小麦茎顶端各类原基的分化一旦启动 ,其分化速率均随着 GDD的增加呈现“慢 -快 -慢”的动态变化规律。虽然不同播期对苞叶原基和小穗原基的分化模式具有调节作用 ,但冬性与春性品种以及主茎与分蘖顶端原基分化的模式基本一致。原基分化热间距 ( GDD/原基 )按叶片—苞叶—小穗次序大幅度降低 ,显示小麦茎顶端原基分化强度具有随生育进程而递增的生物学规律。以 GDD计 ,不同播期之间苞叶原基分化终止期及小穗原基分化始期的差异远远大于苞叶原基分化始期的差异 ,说明小麦温光反应以对小穗原基分化期的调控作用为主。冬、春性品种主茎、分蘖的苞叶原基数 ( x)与小穗原基数 ( y)之间的相关均极显著 ,可统一用方程 y=1.812 +0 .

It was found that S shape curves could describe leaf, bracteal and spikelet primordium differentiation in relation to GDD. The Logistic equations of the three types of S curves were all highly significant with R 2 greater than 0.74. The apex primordium differentiation exhibited similar patterns to winter and spring type varieties on main stem and tillers, but marked differences among different sowing dates. The thermalchrons of apex primordium differentiation were reduced greatly in the order of leaf. bracteal and spikelet, and thus the rates of apex primordium differentiation were accelerated with plant development progress. Measured with GDD, differences between different sowing dates for the end of bracteal primordium differentiation and beginning of spikelet primordium differentiation were much greater than for the beginning of bracteal primordium differentiation, indicating that impact of phasic development was primary on spikelet primordium initiation in wheat. Bracteal primordium number ( x ) was significantly correlated with spikelet number ( y ) in the two types of varieties, as well as in main stems and tillers, with an integrated single equation as y =1.812+0.897 x .