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三清山濒危植物天女花种群生殖对策研究

Reproductive Strategy of Endangered Plant Magnolia sieboldii in Sanqing Mountain

  • 摘要: 天女花是国家Ⅲ级保护植物,为了解其生存状况、生殖潜能、生态对策以及为该植物的保护提供理论依据,运用种群年龄结构、生殖力表和生殖值表,研究了三清山濒危植物天女花(Magnolia sieboldii)在三清宫和玉京峰4个样地中的种群动态及生殖策略。结果显示:(1)三清山天女花种群幼苗较少(8.8~12.3株/100 m2),中龄个体数量多(12.0~15.0株/100 m2);(2)4个样地种群生育力均较低,但生境较好的样地最低(177.0粒/株),而生境较差的样地最高(218.3粒/株),生殖适度与之相反;(3)生殖值Vx极大值出现的时间与群落的稳定性相反,较差的生境条件往往导致天女花最短时间内达到最大生殖阶段;(4)天女花种群生殖投资较少,生态对策总体属于k对策者,但在较差的生境中表现出增大生殖投资,即存在r对策种群特征;(5)海拔、郁闭度、坡向和岩石裸露率对天女花生殖产生显著影响,与天女花生殖指标表现为多元线性关系。

     

    Abstract: Magnolia sieboldii is placed in the third class in rank of key species for conservation in China.To determine their living status,reproductive potential,ecological countermeasures and provide a theoretical basis for the conservation of this endangered plant,this paper studies the species’ dynamics and reproductive strategy of the endangered plant in four sampling sites using age class,fecundity schedule and reproductive value.The results showed that: (1) Magnolia sieboldii seedlings were less (8.8-12.3 individual/100 m2),while the number of middle aged individuals (12.0-15.0 individual /100 m2) was more than other plants. (2) The population fecundities were low and differed in the four plots,with the lowest fecundity (177.0 seed/individual) in better habitat and the highest (218.3 seed/individual) in poor habitat.(3) The maximum reproductive value increased with decreasing stability of the community,which often led to Magnolia sieboldii reaching maximum reproductive stage in poor habitat at the shortest time.(4) Ecological countermeasures of Magnolia sieboldii showed mainly the k-strategy characteristics,but in less stable community the reproductive parameters were greatly changed,showing an r-strategy characteristics.(5) Altitude,slope aspect,canopy density,and percentage of exposed rock,significantly affected the reproductive index of Magnolia sieboldii.Stepwise regression analysis showed that multiple linear relationships appeared between reproductive index of Magnolia sieboldii and environment factors, removed the moisture content of soil and litter layer.

     

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