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研究了梭梭(Haloxylon ammodendron)种子密度对萌发和幼苗生长、存活的影响及其对梭梭种群更新的作用。在自然条件下设置80、160、320、480、640、960粒·m-2等6个种子密度处理,每个处理5次重复,对梭梭种子萌发和幼苗生长进行了全生长季观测。结果表明:种子萌发率随密度的增加呈增长趋势,在密度为80粒·m-2时,萌发率为28%,当密度达到960粒·m-2时,萌发率为54%;幼苗存活率随种子密度增加呈现先增加后减小的趋势,160粒·m-2种子密度下出土幼苗存活率最高为25%,320粒·m-2种子密度下出土幼苗存活率最高为22%,当密度增加到960粒·m-2,萌发出土的幼苗成活率为11%;综合考虑种子萌发率和幼苗存活率,在1cm沙埋深度下320粒·m-2为最佳密度。幼苗生长高度会受到幼苗数量的影响,单位面积上一定范围内幼苗数量增加可以使幼苗生长高度增加,但当幼苗数量超过一定范围,幼苗生长减慢。单纯从幼苗数量来看,种子密度越大,幼苗更新数量越多。
The effects of Haloxylon ammodendron seed density on germination and seedling growth and survival and their effects on population regeneration of Haloxylon ammodendron were studied. Six seed density treatments of 80, 160, 320, 480, 640 and 960 grains · m-2 were set up under natural conditions. Five replicates were made for each treatment. The whole growth seasons of H. ammodendron seed germination and seedling growth were observed. The results showed that the germination rate of seeds increased with the increasing of density, the germination rate was 28% when the density was 80 grains · m-2, and the germination rate was 54% when the density reached 960 grains · m-2; The seed germination rate increased firstly and then decreased with the increase of seed density. The highest seedling survival rate was 25% at 160 grain · m-2 seed density, the highest seedling survival rate was 22% at 320 grain · m-2 seed density, When the density increased to 960 seeds · m-2, the survival rate of seedlings germinated was 11%. Considering seed germination rate and seedling survival rate, 320 grains · m-2 was the optimal density at 1 cm sand burial depth. The height of seedlings will be affected by the number of seedlings. Increasing the number of seedlings within a certain area per unit area can increase the height of seedlings, but when the number of seedlings exceeds a certain range, the growth of seedlings will slow down. Pure seedling from the point of view, the greater the seed density, the more the number of seedlings to update.