沙埋对小叶锦鸡儿幼苗生长和生物量分配的影响

Effects of different sand burial depths on growth and biomass allocation in Caragana microphylla seedlings

沙埋是沙地植物生长和分布的重要选择压力之一,是影响植物种子萌发、幼苗出土和幼苗存活的关键因素。本研究对科尔沁沙地常见的沙生灌木小叶锦鸡儿(Caragana microphylla)幼苗进行了不同深度的沙埋试验。结果表明:各处理间叶片数量在沙埋初期有差异,后期差异不显著;各处理植株生物量均主要分配在叶片中,随着沙埋深度的增加叶片生物量比逐渐降低,而茎生物量比逐渐增加。当沙埋深度达到其株高的133%时,可使幼苗全部死亡;而在沙埋深度与株高相同时,其存活率仅为37%。沙埋30天后,中度沙埋(67%)能促进小叶锦鸡儿幼苗的株高、根长、总生物量以及根茎相对生长速率的增加;而重度沙埋抑制植株地上部分的高生长和叶相对生长速率。这说明中度沙埋在一定程度上可以促进小叶锦鸡儿的生长,而重度沙埋抑制幼苗的生长,甚至导致幼苗的死亡。

Sand burial is one of the main stresses on growth and distribution of sandy plant, and it is also the main factor that affects seed germination, seedling survival and growth in sandy land. Caragana microphylla is one of the commonly occurred psammophilous shrub species in the Horqin Sandy Land. The study to Caragana microphylla is to examine the impact of various sand burial depths on its growth and biomass allocation. The results are as follows： the burial at depth of 133% of their shoot height led to death of all seedlings, and when burial depth was up to 100 % of their shoot height, only about 37% seedlings were alive. Leave number were different among treatments in early days, but no significant difference in late time. After thirty days burial, the burial at depth of 67 % of their shoot height could enhance seeding height, root length, biomass, relative growth rate of root and stem; but the burial at depth of 100% of their shoot height restrained seedling height and relative growth rate of leaves. There were no significant changes ial depth increasing, of Caragana Key Words： in their biomass allocation pattern among four treatments, leaves biomass decreased with burbut stem biomass increased. The result showed that moderate burial could promote the growth microphylla, but intensive burial could restrain its growth, even lead the seedling to die.