Abstract: Leymus chinensis, a perennial grass with well-developed rhizome and seed-shattering phenomena was chosen as a species to reveal the relative factors of seed shattering. Microscopic observations indicated the formation of abscission layers between spikelet pedicels and seed stalks during the course of seed maturity which was an important reason for seed shattering. Although there were full developed abscission layers in the seed stalks of base spikelets, seeds were not ready to shatter. Various L. chinensis accessions showed a wide variation of seed-shatter rate. The rate of seed shattering was in the range of 22.8% to 79.9% and the rate of fruit setting was in the range of 23.1% to 98.4%. The width of caryopsis and rate of seed shattering showed positive correlation. The seeds of some accessions, such as S4-3 and S5-3, shattered and germinated under natural conditions soon after maturity showing no dormancy in these accessions.

Key words: Leymus chinensis, Seed-shattering, Abscission layer, Relevant traits, Seed setting rate, Seed dormancy

摘要： 羊草(Leymus chinensis)是多年生根茎型乡土草,存在落粒性特征,为揭示羊草的落粒情况及其相关因素,通过对羊草穗结构的显微观察发现,在其种子成熟过程中,小穗轴和种柄之间形成离层,它是导致种子自然脱落的重要原因。羊草小穗最基部的种子虽然在种柄基部有发育完全的离区,但不易脱落。通过采集不同品系和不同时期的羊草小穗并对其上的种子数量等数据的研究发现,羊草落粒性在不同品系间存在明显差异,其落粒率的范围在22.8%~79.9%之间,结实率范围在23.1%~98.4%之间,羊草颖果宽度与落粒率成正相关。研究还发现,S4-3和S5-3等羊草材料的种子成熟后自然落粒并很快萌发,说明这些品系的种子不存在休眠现象。

关键词: 羊草, 落粒性, 离层, 落粒相关性状, 结实率, 种子休眠