准噶尔盆地梭梭土壤种子库基本特征

土壤种子库是种子的安全岛，是干旱荒漠区植被更新与恢复的基础。以梭梭为主的荒漠植被是准噶尔盆地绿洲区重要的生态屏障，但是，对于与梭梭种群自然更新紧密联系的土壤种子库特征的研究却相对缺乏。本研究通过野外采样、物理筛分并结合室内实验分析，对准噶尔盆地梭梭土壤种子库基本特征进行了研究。结果表明：（1）梭梭种群平均土壤种子库密度从71~696 粒·m^-2，局部小环境甚至达到7 534 粒·m^-2；（2）变异系数分析表明，各种群土壤种子库密度变异系数均大于1，说明梭梭土壤种子库的数量分布是非常不均匀的；（3）梭梭种群土壤种子库中种子萌发率从2.08%到47.62%不等，平均约18%；（4）变异函数分析表明，梭梭土壤种子库中种子分布的空间变异较大。综上，准噶尔盆地梭梭土壤种子库密度大且种子萌发能力强，同时其时空分布差异明显，这些特征均将影响梭梭种群的分布格局和种群更新。

Basic Characteristics of Soil Seed Bank of Haloxylon ammodendron in Junggar Basin

Soil seed bank is the refuge of seed and the basis of vegetation regeneration and recovery in arid desert region. Haloxylon ammodendron-based desert vegetation is the important ecological barrier of Junggar Basin's oasis area, however, the researches of soil seed bank characteristics which are closely related to population regeneration of H.ammodendron are relatively lacking. Basic characteristics of the soil seed bank of H.ammodendron in Junggar Basin were researched by field sampling,physical screening and laboratory experimenting. The results showed that:(1)The soil seed bank densities of H.ammodendron populations varied from 71 to 696 seed·m^-2, especially in some local environments it reached 7 534 seed·m^-2. (2)The coefficient of variation analysis identified that the coefficients of variation of the soil seed bank density were more than 1. It meant that the quantitative distribution of soil seed bank was very uneven. (3)The seed germination rates in the soil seed banks varied from 2.08% to 47.62% and the average was approximately 18%. (4)The analysis of variogram indicated that there were obvious differences in the spatial distribution of seeds in the soil seed bank of H.ammodendron populations. In summary, the characteristics of high density, germination ability and spatial variability would effect on the distribution pattern and regeneration of H.ammodendron populations.