通过野外监测和模拟试验，研究了铁路沿线沙区段3种沙生植物未埋藏直立植株个体的植冠种子库种子的季节脱落动态、植冠种子库对土壤种子库的补充动态及植冠储藏种子的活力和萌发特性。结果表明，（1）在风季即将结束生长季即将开始的时候，铁路沿线沙生植物差巴嘎蒿（Artemisia halodendron）的植冠种子库存留着最多的瘦果与头状花序，表现出将种子的脱落延迟到风季结束及雨季来临时的特点。推迟脱落传播体的时间表现为差巴嘎蒿大于冷蒿（A. frigida）和万年蒿（A. gmelinii），即随着沙丘流动性的增强，植冠种子库推迟脱落种子的程度逐渐增强。（2）植冠种子库对植株周围的土壤种子库起到补充作用，且差巴嘎蒿植冠种子库对土壤种子库的最大补充出现在风季结束雨季开始时期（种子成熟翌年5月）。（3）在风季即将结束雨季即将开始时，差巴嘎蒿植冠储藏种子80%以上具有活力，而冷蒿、万年蒿植冠储藏种子中有活力的种子占比不足20%。铁路沿线沙区段沙生植物的植冠种子库使种子的脱落及对土壤种子库的补充避开风季、迎合雨季，减少了由风季风蚀和沙埋所造成的种子损失，实现了种子的持续供应，同时以这种方式将保持活力的种子延迟至条件适宜时脱落并快速萌发，在一定程度上分摊了种群生存的风险，使种群得以持续繁衍。铁路沿线沙区段沙生植物独特的繁殖对策所反映出的生态功能对铁路沿线沙区段的土壤植被恢复研究具有重要的科学指导意义。%Seed (achene and capitulum) persistence on the parent plants, the supplement for the soil seed bank, and the maintenance of seed viability of 3 psammophyte were studied by means of field investigations and simulation experiments in sand dune areas along with the railway line. The results showed that: 1)Artemisia halodendronretained the highest number of achene and capitulum among the three study species at the end of the windy season and the start of the growing season. The delayed dispersal of achenes and capitulums differed interspecifically: the retention time wasA. halodendron >A. frigida andA. gmelinii. The persistence of canopy seed bank increased with intensifying of sand mobility; 2) Achenes were found in the soil for the 3 studied species. The maximal supplement to the soil seed bank forA. halodendron occurred in the end of windy season and the start of rainy season (the following May after maturation); 3)A. halodendron had seed viability which was higher than 80%, andA. frigida andA. gmelinii had seed viability which was less than 20% in the end of windy season and the start of rainy season. The selected psammophyte postponed seed dispersal before the end of the windy season and the onset of the rainy season. It reduced the seed loss which caused by wind erosion and sand burial, and provided the continuous supplement of seed. Canopy seed bank in sand dune areas along with the railway line played important roles in adjusting seed dispersal and timing of seed germination and seedling emergence and alleviating the impacts on seed availability and seedling recruitment, which made enlargement of population easier. The special ecological function of canopy seed bank contributes to the vegetation restoration along with the railway line of sand dune areas.
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