【摘要】 以样地每木检尺资料为基础,依据"空间差异代替时间变化法"以及"样地编年序列法"的原理,探讨了中国沙棘Hippophae rhamniodes subsp.sinensis平茬萌蘖种群的密度动态及其调节规律。结果表明:通过萌蘖植株、分蘖和构件密度制约的出生与死亡调节,中国沙棘从个体数量、分株形态、构件生物量分配等不同层次维持种群适宜的数量和结构。①种群通过萌蘖植株的出生与死亡调节不断改变着种群密度,依次可将种群密度动态分为上升、下降和平稳等3个阶段。②种群通过分蘖的出生与死亡调节,不断改变着萌蘖植株的形态。随着种群基盖度的增大,合轴型分株的比例下降而单轴型分株的比例上升。③种群通过构件的出生与死亡调节,不断改变着构件的生物量分配。随着种群基盖度的增大,枯枝生物量分配上升而叶片生物量分配下降,克隆器官和根系的生物量分配均呈下降趋势。④研究对象的生物量分配已趋于平稳,亟待再次平茬或创造林窗恢复种群的繁殖、生长和存活能力。由此可得出结论:中国沙棘平茬后,通过克隆植株、分蘖及构件的密度制约出生与死亡调节,使种群形成与环境资源供应水平相适应的个体数量与分株形态,从而实现对生境资源的合理利用以及种群持久性的维持。更多还原

【Abstract】 Stumping is one of the important methods for tending management and restoration of population stability.In order to understand the adjustment regulation of density change which could provide scientific basis for population restoration and management of stump sprout,the density dynamic of stump sprout population was studied.Based on measurement of all individuals in a population of Hippophae rhamnoides subsp.sinensis at different successional stages,model adjustments of density dynamics and stump sprouts in the Mu Us sandy lands of north central China were analyzed using a spatial series substituted for a time series and plots arranged by age.In a model with variables of individual number,ramet morphology,and biomass adjustments were made by changing sprout and surviral rates of regenerated plants,ramet number,and plant density.Results showed that(1) population density had three stages increasing,decreasing and steady in turn;(2) morphological changes of regenerated plant included an increased population base diameter a decreased ratio of complex axis and an increased ratio of single axis;(3) biomass distribution constantly changed with sprout and survival adjustments.As the population base diameter increased,the dead branch biomass ratio increased and leaf biomass ratio decreased.Meanwhile,the ratios of clonal organs and mean root all decreased.Since growth and survivability could improve with a further stump sprouting,individual number and ramet morphology could be improved by adjusting the sprout and survival rate of clonal plants and ramets to help realize a rational utilization of the resource and maintenance of the population.更多还原