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准噶尔无叶豆(Eremosparton songoricum(Litv.)Vass.)是中亚荒漠特有种,中国的单属种植物类群,稀有种,仅片段化分布在古尔班通古特沙漠风蚀坡地及流动-半流动沙丘上。按照不同微地形条件,于2008年9月、2009年的4月及6月分别对两个自然种群8种微地形条件(A种群为积沙灌丛下、积沙平缓处、风蚀灌丛下和风蚀平缓处4种;B种群为沙丘上部、中部、下部及底部4种)进行土壤种子库取样,并统计萌发季节的自然种群萌发率,同时对比室内萌发率,以研究土壤种子库的时空分布特征及其对种子萌发的影响。结果表明,从9月至次年4月和6月,种群种子库密度逐渐减少。自然状态下沙埋深度0—6cm的种子能够萌发,主要萌发季节(4月)A种群有42%～73.56%的种子、B种群有63.33%～72.73%的种子分布在沙土6cm以下的深度,为“无效种子”。A种群积沙灌丛下种子库密度值最大,但萌发季节的自然种群萌发率为0;B种群的沙丘下部种子库密度较大,但自然种群萌发率仅为4.8%±0.8%。不同微地形条件下沙粒打磨作用(去除种子硬实)和水分条件的差异,是微地形间种子萌发率差异的主要原因。本研究从土壤种子库角度解析自然种群有性更新困难的原因,为该稀有物种的保育提供理论依据。
Eremosparton songoricum (Litv.) Vass. Is a endemic species of Central Asia endemic to China. It belongs to a single genus and species of rare species in China, and is only fragmented in the wind erosion slope and flow-half of the Gurbantunggut Desert Mobile dunes. According to the different micro-topography conditions, eight micro-topographical conditions of two natural populations were collected in September 2008 and April 2009, respectively (under the sediment shrubs, And 4 kinds of gentle wind erosion; B population was the upper part of the sand dune, middle part, bottom part and the bottom of 4 species) soil seed bank sampling, and the germination rate of natural population in the germination season statistics, compared with indoor germination rate to study the spatial and temporal Distribution Characteristics and Their Effects on Seed Germination. The results showed that from September to April and June of the next year, population density of seed banks gradually decreased. Under natural conditions, seeds with 0-6cm sand depth could germinate. In the main germination season (April), seed of A population was 42% -73.56%, seed of B population was 63.33% -72.73% “Invalid seed ”. The density of seed bank was the highest in A-type sediment shrubs, but the natural germination rate was 0 in the germination season. The density of seed bank in the lower part of B-seed population was larger but the germination rate of natural population was only 4.8% ± 0.8%. The difference of seed germination rate between micromorphs under different microtopography is related to the difference of sand grinding (removal of seed hard) and water conditions. In this study, the reasons for the difficulty of sexual regeneration of natural populations were analyzed from the perspective of soil seed bank, providing a theoretical basis for conservation of this rare species.