沙坡头人工固沙区的种子库动态

THE DYNAMICS OF SEED BANK ON SHAPOTOU ARTIFICIALLY STABILIZED DUNES

沙坡头人工固沙区的土壤种子库中共有４６种植物的种子，属于１７个科。其中菊科植物最多，达１１种；其次为藜科，７种；禾本科７种；豆科４种。既是现有植被组分种，其种子又存在于种子库中的，占总种数的３３．３％ 。油蒿（Ａｒｔｅｍ ｉｓｉａ ｏｒｄｏｓｉｃａ）、花棒（Ｈｅｄｙｓａｒｕｍ ｓｃｏｐａｒｉｕｍ ）和柠条（Ｃａｒａｇａｎａ ｋｏｒｓｈｉｎｓｋｉｉ）的种子产量为５４５±６７６．７３粒／ｍ ２、６．６７±１３．７４粒／ｍ ２、０．０３２±２．４３×１０－ ３粒／ｍ ２。油蒿在植株上成熟时不受虫害，而花棒、柠条的种子受害比例分别为３１．９２％ 和８３．２９％ 。在最适埋藏深度下，油蒿、柠条、花棒种子的累积发芽率分别可达７８．３％ 、８５．０％ 和６６．７％ ；萌发速度：油蒿＞ 柠条＞ 花棒。根据种子库动态分析和植被调查结果可初步预测：沙坡头人工固沙植被的演替趋向将是灌木以油蒿为主，草本以雾冰藜（Ｂａｓｓｉａ ｄａｓｙｐｈｙｌｌａ）。

There were 46 species belonging to 17 families in the soil seed bank on Shapotou artificially stabilized dunes. Compositae was the family with most species (11 species) and the others were Chenopodiaceae (7 species), Gramineae (7 species), Leguminosae (4 species), etc. 33 3% of the species lived in the community also had seeds in soil. The seed production of Artemisia ordosica, Hedysarum scoparium, Caragana korshinskii was 545 57±676 73 grains/m 2, 6 67±13 74 grains/m 2, 0 032±0 024 grains/m 2, respectively. The seeds of A. ordosica were not destroyed by pests, but 31 9%, 83 29% of the seeds of H. scoparium, C. korshinskii respectively were destroyed by pests. Under the most suitable burying depth, the cumulative seed germination rate of A. ordosica, H. scoparium, C. korshinskii were 78 3%, 66 7%, 85 0%, respectively. The rate of germination was: in the order of: A. ordosica>H. scoparium>C. korshinskii. The vegetation succession would tend towards community mainly consisted of A. ordosica, Bassia dasyphylla, Eragrostis poaeoides, etc.