不同落粒时间无芒雀麦种子形态与萌发特性

【目的】不同落粒时间无芒雀麦种子形态与萌发特性，种子脱落是植物为应对复杂多变的自然环境及种群繁衍而表现出的生存策略，而脱落时间的早晚对种子的发育情况产生重要影响。【方法】以天山北坡中段原生境野生无芒雀麦(Bromus inermis)居群为材料，研究4个不同自然脱落时间种子的长、宽、厚、附属物(外稃长、内稃长、芒长)、种子重量，以及发芽率、发芽势、萌发指数和平均发芽速度，分析自然落粒时间差异对种子形态及萌发特性的影响。【结果】无芒雀麦的落粒率在4次收集时间分别为2.87%、2.55%、2.87%及3.49%;随着脱落时间的推移，种子形态特征整体表现出种子长、宽、厚及种子重量增加，外稃长、内稃长先减后增，芒长呈减小的趋势，芒长较长的种子最容易脱落；随着脱落时间的推移，种子发芽率、发芽势、萌发指数增加，平均发芽速度减小；落粒率与芒长呈极显著正相关关系，相关系数达到1.000。【结论】自然状况下，野生无芒雀麦属于弱落粒性种质；脱落时间的推迟不但使种子大小变大，而且增加了种子的重量，进而提高了种子的萌发能力。

Seed Morphology and Germination Characteristics of Bromus inermis at Different Seed Shattering Times

【Objective】 Seed morphology and germination characteristics of Bromus inermis at different seed shattering times.【Method】 In this project, the seeds of wild Bromus inermis populations in the middle part of the northern slope of Tianshan Mountain were used as research materials.The length, width, thickness, appendages (lemma length, palea length, awn length), seed weight, germination rate, germination potential, germination index and average germination rate of seeds with different natural falling time were studied to explore the effects of different natural falling time on seed morphology and germination characteristics.【Result】 The seed shattering rate reached 2.42%, 2.45%, 2.95% and 3.82% respectively in the four collection times; with the lapse of abscission time, the seed morphological characteristics showed that the seed length, width, thickness and seed weight increased, the lemma length and palea length decreased first and then increased, and the awn length decreased, and the seeds with longer awn length were most likely to fall off; with the lapse of abscission time, the seed with longer awn length was more likely to fall off, the germination rate, germination energy and germination index increased, but the germination velocity decreased; there was a significant positive correlation between the seed shattering rate and awn length, and the correlation coefficient was 1.000.【Conclusion】 It can be seen that under the condition of natural abscission, the seed shattering rate of wild B.inermis reaches the maximum of 3.82% in the yellow withered stage.The delay of abscission time not only makes the seed volume larger, but also increases the weight of the seed, thus improving the germination ability of the seed.