两种梭梭出苗对生境土壤基质互换与沙埋深度的响应

Response of Seedling Emergence of Two Haloxylon Species to the Interchanging of Soil Matrix in Habitants and Sand Burial Depth

以梭梭(Haloxylon ammodendron)、白梭梭(Haloxylon persicum)两种植物为研究对象,采用生境土壤基质互换种植和盆栽控制沙埋深度方法,对其萌发出苗和幼苗建成进行对比研究。结果表明:丘间低地土壤pH、电导率和养分含量均显著高于沙丘顶部,其中电导率(可溶盐含量)相差达5倍;土壤含水量差别不显著。在萌发定居过程中,沙丘顶部幼苗密度白梭梭大于梭梭,而丘间低地则相反;基质互换种植白梭梭和梭梭幼苗的总密度均是原始生境比互换生境高,显示出明显的微生境差异,说明白梭梭对养分贫瘠的沙丘顶部适应性、定居能力比梭梭强;对于盐分含量较高的丘间低地,梭梭的适应性、定居能力则比白梭梭强。两种植物出苗率都随沙埋深度增加而降低,且在同一沙埋深度下,白梭梭幼苗死亡率明显低于梭梭,梭梭在0～3 cm深度有出苗现象,最佳沙埋深度为0.5 cm;白梭梭在0～5 cm深度有出苗现象,最佳沙埋深度为0～3 cm。此外,两种梭梭开始出苗所需时间受沙埋影响显著,沙埋越深,出苗所需时间越长,相同处理下,白梭梭开始出苗所需时间均比梭梭长,但其绝对高度生长率、生物量、根冠比、株高以及主根长度都明显高于梭梭,说明白梭梭耐沙埋能力、在沙生环境下生长能力均比梭梭强。

Field interchanging transplants and sand burial controlled experiments were conducted on Haloxylon ammodendron and H.persicum to compare the seed germination,seedling emergence and seedling growth.The results are as follows：（1） The pH value,EC and nutrient content in interdune soil were higher than that on dune top,especially the difference of EC is five times;（2） The density of H.persicum seedlings was always higher than that of H.ammodendron during seedling growth on dune top,but the situation was contrary in the interdune lowland;total seedling densities of H.ammodendron and H.persicum were higher on their own soil type,this differed significantly among the two microhabitats.Results reveal that the regeneration capability and adaptability of H.persicum were higher than those of H.ammodendron for the barren dune top soil,but the situation was contrary for the interdune lowland;（3） Emergence rate of the two species was decreased with the increase of sand burial depth,and at the same sand burial depth,the mortality of H.persicum seedlings was lower than that of H.ammodendron.H.ammodendron emerged at sand burial depth of 0-3 cm,and its optimal burial depth was 0.5 cm.H.persicum emerged at all sand burial depths,and its optimal burial depth was 0-3 cm.Date of beginning to emerge was significantly affected by sand burial depth,and at the same sand burial depth,the emergence time of H.persicum was later than that of H.ammodendron.However,the growth rate of absolute height,biomass,shoot-root ratio,shoot length and root length of H.persicum were higher than those of H.ammodendron,and the growth rate of absolute height of H.persicum was significantly affected by sand burial depth.These results reveal that the capability of enduring sand burial of H.persicum is higher than that of H.ammodendron,and H.persicum is easier to survive in severe microhabitat with sand burial and wind erosion.