克隆植物中国沙棘种群动态及其生物量调节机制

以沙棘人工林为材料,样地调查数据为依据,以子株种群密度表示子株出生与存活能力,对其种群密度、生物量、年龄结构、克隆器官生物量投入与分配的时间动态规律及关系进行了分析。结果显示:随着种群年龄增大,子株个体数量占种群个体总数量的比例由0提高到95.5%,子株种群密度呈先上升后下降再回升趋势; 克隆种群年龄结构随子株种群密度的改变,从增长型(稳定型)演变为衰退型再演变为增长型。然而,子株种群密度与克隆器官生物量投入及其分配之间呈极显著正相关。且在种群恢复过程中,生物量投入与分配的回升相对于子株种群密度回升具有前置效应。因此,种群通过克隆器官生物量投入与分配格局调节制约子株的出生或存活从而改变子株种群密度,而子株种群密度变动过程决定克隆种群密度消长、年龄结构演变规律。根据沙棘克隆种群密度消长规律、年龄结构演变规律及其与克隆器官生物量投入、分配调节的内在联系,可将中国沙棘人工种群动态分为3个阶段:克隆生长旺盛期,克隆器官生物量投入及其分配随着种群年龄增大而上升,克隆种群密度随之上升,年龄结构为增长型(稳定型); 克隆生长衰退期,克隆器官生物量投入及其分配随着种群年龄增大而下降,克隆种群密度随之下降,年龄结构从增长型(稳定型)演变为衰退型; 克隆生长恢复期,克隆器官生物量投入及其分配随着种群年龄的增大而回升,克隆种群密度随之回升,种群年龄结构从衰退经过恢复又演变为增长型。

A study on the population dynamics and its biomass adjustment mechanisms of clonal plant Hippophae rhamnoides L. ssp. sinensis

Natural forest of Hippophae rhamnoides L. ssp. sinensis can maintain stability or persistence of population by adjusting clonal propagation, but we know little about the relationship between the dynamics of plantations and the adjustment of clonal propagation. Here, we used plantations of Hippophae rhamnoides L. ssp. sinensis as materials and used density of daughter ramet population as the indicator of propagation and survival to analyze the dynamic patterns and relationships of population density, biomass, age structure of population, and biomass investment and allocation of clonal organs, on the basis of survey data in the plot. The results showed that, when the age of clonal population rose, the percentage of daughter ramets in the total population increased from 0 to 95.5%. The density of daughter ramet population rose at the beginning then declined later, and become resilient at last. With the change of density of daughter ramets, the age structure of clone population changed from rising(stable)type into declining type, and finally recovered to rising type. However, there was an extremely positive correlation between density of daughter ramet population and biomass investment and allocation of clonal organ. The biomass investment and allocation of clonal organ presented the “prepositive effect” in the process of population recovery. These results showed that, the population regulated and restricted the birth or survival of daughter ramets by regulating biomass investment and allocation of clonal organ to change the population density of daughter ramets. The change process of density of daughter ramet population determined the density change of clonal population and the changing process of age structure. Based on the changing principle of the density of clonal population, the changing process of age structure, and the inherent relationship between the changing process of age structure and the regulation of biomass investment and allocation of clonal organ, the changing dynamics could be divided into three stages: the vigorous stage of clonal growth, in which biomass investment and allocation of clonal organ rose along with the increasing of population age, leading to the rising of the density of clonal population. The age structure in this stage is rising or stable. The declining stage of clonal growth, in which biomass investment and allocation of clonal organ declined along with the increasing of population age, leading to the decline of the density of clonal population. The age structure in this stage changed from rising(stable)type into declining type. The recovery stage of clonal growth, in which biomass investment and allocation of clonal organ recovered along with the increasing of population age, leading to the recovery of the density of clonal population. The age structure in this stage changed from declining type to rising type by a short recovery.