生境对无芒雀麦幼穗分化进程及生殖格局的影响

以乌苏1号无芒雀麦为材料，设置2个生长环境（荒漠绿洲区、高海拔地带），通过观测幼穗分化进程及开花习性，探究生境对无芒雀麦幼穗分化及生殖格局的影响。结果表明，无芒雀麦幼穗分化从分蘖期开始至抽穗期结束，分为初生期、伸长期、结节期、小穗原基分化期、小花原基分化期、雌雄蕊原基分化期、雌雄蕊形成期和完穗期8个时期。幼穗分化是从生长锥顶端第1枝梗原基与小花原基开始分化，相同小枝梗上原基与小花原基均是自下逐渐向上发育；整穗是从顶部向下逐渐开花，下部枝梗开花时间小于上部枝梗；小穗上的小花由下向上逐步开花。与荒漠绿洲区相比，高海拔地带的无芒雀麦幼穗分化时间晚，周期缩短，穗部赤霉素（GA）、脱落酸（ABA）及叶片可溶性蛋白含量相对较高，细胞分裂素（CTK）含量和种子千粒重较低，但高海拔地带单穗成熟种子粒数与单位面积内种子产量高，更适合无芒雀麦种子生产。

Young spike differentiation and reproductive pattern of Bromus inermis in different habitats

In this study， we explored the effects of habitat on young spike differentiation and the reproductive pattern of Bromus inermis cv. Wusu No.1. We compared the process of young spike differentiation and flowering habits between plants in two growth environments： a desert oasis area and a high altitude area. The results showed that the young spike differentiation of B. inermis extended from the tillering stage to the heading stage， and could be divided into eight stages： the vegetative stage， elongation stage， single ridge stage， spikelet primordial stage， floret primordial stage， stamen primordial formation stage， stamen formation stage， and spike completion stage. Young spike differentiation started from the first branch primordium and floret primordium at the top of the growth cone. The primordia on the same branchlets and floret primordia developed from bottom to top. The flowering sequence of the whole spike was from top to bottom， and the flowering time was shorter on the lower branches than on the upper branches. The florets on the spikelets bloomed from bottom to top. Compared with the plants in the desert oasis area， those in the high altitude area differentiated young spikes later， had a shorter cycle， had higher contents of gibberellin， abscisic acid， and leaf soluble protein in the spike， lower cytokinin content and 1000-grain weight， and higher number of mature seeds per spike and seed yield per unit area. These results show that the high altitude area is more suitable for B. inermis seed production.