科尔沁沙地农田-沙丘交错区白草无性系的生态适应性分析

Ecological adaptability of Pennisetum centrasiaticum clones on farmland-sand dune ecotone of Keerqin sandy land.

对生长在不同沙地生境下的白草无性系进行了个体生长与形态以及种群生物量等指标的比较研究 .结果表明 ,生长在不同生境下的白草无性系表现出显著的形态可塑性和不同的生物量分配模式 .生长在农田 沙丘过渡带上的白草无性系与生长在半固定沙丘上的白草无性系相比 ,具有更大的生物量 ,更快的叶片延伸速率 ,根茎总长度和节间长度更长 ,不定芽更多 ,地下生物量所占比例更大且分布更深 ;这些特征的出现与农田 沙丘过渡带上土壤表层比较疏松而下层水分状况相对优越有着密切关系 ,因而生长在农田 沙丘过渡带上的白草无性系能更快地拓展其生存空间 ,在固沙和沙生植被演替中起重要作用 .

The individual growth,morphology and population biomass of Pennisetum centrasiaticum clones at two different habitats of farmland-sand dune ecotone on Keerqin sandy land of Inner Mongolia were compared in this study.P.centrasiaticum clones had significant morphological plasticity and different biomass distribution pattern at different habitats.Compared with P.centrasiaticum clones on semi-fixed sand dunes,those on farmland-sand dune transitive zone had a greater leaf elongation,longer rhizomes and internodes,more adventitious buds,larger amount of biomass,and deeper distribution of underground biomass,which were closely associated with the losse texture of the upper soil and the rather favorable water condition of the lower soil.It is believed that the population can well adapt itself to the farmland-sand dune ecotone habitats,and thus,play an important role in fixing mobile sand in succession of arenaceous vegetation.