荒漠绿洲边缘区泡泡刺灌丛土壤种子库研究

Study on Soil Seed Bank of Nitraria sphaerocarpa Coppice Dune in a Desert-oasis Marginal Zone

通过研究黑河中游荒漠绿洲边缘区泡泡刺灌丛的土壤种子库特征，结果表明，无论5月，还是9月，迎风坡和背风坡的土壤种子平均数量，都受到水平距离和土壤深度的显著影响。水平方向上，种子密度从灌丛下面到灌丛间地逐渐减少，而且大部分种子分布在灌丛下面，几乎没有种子分布在灌丛间地。垂直方向上，在0～10cm范围内，5月份种子数量随着土壤深度的增加而增加。5～1cm种子数量最多，然后随着土壤深度的增加而降低。5～10cm迎风坡和背风坡的种子密度分别为4292粒／m^2和28119粒／m^2，显著大于其他深度的种子密度，占总种子数量的82．4％左右。9月份，无论迎风坡和背风坡，种子数量随着土壤深度增加而降低，大约有84％的种子集中在0～5cm，很少有种子存在于10～20cm土层。

Nitraria sphaerocarpa, one of the main psammophytes, grows in patches and is distributed in discontinuous pattern in the arid and semiarid areas of China. In this study, the soil seed bank of Nitraria sphaerocarpa in a desert-oasis marginal zone is lucubrated, and the horizontal and vertical distribution patterns of the seed bank are analyzed. The results show that the seed density of both windward and leeward slopes is closely related to the horizontal distance and the vertical depth of sampling in both May and September. Horizontally, the seed density decreases from the shrub canopy center to the inter-shrubbery area, and most seeds are distributed under shrub canopies. Vertically, the seed density in May increases with increasing soil depth, there are 4 292 and 28 119 seeds per square meter at soil depth of 5 ～ 10 cm in windward and leeward slopes respectively, the proportion of seeds at soil depth of 5 ～ 10 cm is 82.4%, and then the seed density decreases with increasing soil depth. The seed density in September decreases with increasing soil depth whether in windward or leeward slope, 84% seeds are distributed at soil depth of 0～5 cm, and few seeds can be found at soil depth of 10 ～ 20 cm.