作 者 ：刘仲健,陈利君,饶文辉,李利强,张玉婷
期 刊 ：生态学报 2008年 28卷 1期 页码：111~121
关键词：长瓣杓兰；种群动态；Leslie模型；生殖行为；濒危机制；
Keywords:Cypripedium lentiginosum, population dynamic, Leslie Matrix Model, reproductive behaviour, endangered mechanism,
摘 要 ：尽管种群数量动态分析已广泛应用于濒危物种，但很少应用于中国兰科植物。根据中国云南特有的兰科物种长瓣杓兰（Cypripedium lentiginosum）的生物学特征调查和生殖行为观察，计算出其各龄级的存活数、出现频率和子代数，描述其生殖行为和机制。利用基株出现频率计算其空间分布格局；利用其各龄级的存活数和平均生产子代数编制种群静态生命表和生殖力表、绘制存活曲线和年龄锥体，构建Leslie矩阵模型和连续增长模型Nt=658e0.211t对种群数量动态过程进行预测；利用物候特征和传粉生物学观察结果分析其生殖行为和繁殖策略。在此基础上分析其生殖行为与其空间格局、年龄锥体和种群数量动态的关系。结果表明：长瓣杓兰的空间结构为成群分布，种群的年龄锥体属于金字塔-钟型锥体，种群存活表现为DeeveyⅠ型；其种群的净增长率、内禀增长率和周限增长率较高，为增长型种群；种群增长受自身密度影响，连续增长模型不适用该种群的动态预测；引入密度制约因子构建的预测模型Nt=6000/(1+e2.094-0.211t)适用于其种群数量动态预测。长瓣杓兰的生殖行为表现在兼具无性繁殖和有性繁殖，无性繁殖不增加种群的个体数量，仅延续基株的寿命以维持现行种群数量和为有性生殖积累营养。有性繁殖通过花模拟繁殖地欺骗食蚜蝇进入唇瓣而传粉，致使54.37%±6.08%的花产生果实，果实产生充足幼龄植株并多数能进入有性繁殖阶段。有性繁殖在很长的一段时期多次生殖后代而成为种群发展的基础，显示出繁殖方式是影响种群数量动态变化的主要因素。其成功的生殖对策和这种对策在空间格局、年龄锥体上对种群数量动态的影响具有密切的相关性，表明长瓣杓兰的种群发展与其生物学特性相吻合，适生地的生长空间不连续性和狭窄成为其种群发展的制约因素，但该物种现在不需要也不适宜进行迁地保护。
Abstract:Analysis of numeric dynamics of populations has been widely used to study endangered species, however, its application to China orchid is rare. By investigating biological characteristics and reproductive behavior of Cypripedium lentiginosum, an orchid endemic to Yunnan of China, the number surviving in each age-class, the frequency and number of filial generations, and the reproductive behavior and mechanisms are explored. Internal distribution pattern is figured out based on genet frequency; on the basis of the number surviving in each age-class and the number of filial generations, the population static life table and fecundity table are made, the survival curve and age pyramid are drawn, and Leslie matrix model and the density-dependent growth model Nt=658e0.211t are structured to predict numeric dynamics; reproductive behavior and breeding strategy were analysed by observing phenological characteristics and pollination biology. Based on these, we analysed the relationship between the numerical dynamics and reproductive behavior, as well as its internal distribution pattern and age pyramid. We found that C. lentiginosum showed a clumped dispersion distribution pattern, its age pyramid is pyramid-bell shaped, and the population survival exhibited a Deevey I shape; the net reproductive rate and the intrinsic and finite rates of increase for C. lentiginosum were comparatively high, indicating the population is expanding; the population growth is affected by self-density, and the prediction model based on this factor is Nt=6000/(1+e2.094-0.211t), which is suitable for predicting numeric dynamics of C. lentiginosum. The species are endowed with both asexual and sexual reproduction. The former does not increase individual quantity, but sustain the current genetics of the population and accumulate energy for sexual reproduction, while the latter involves pollinating flowers by mimicking brood-site to lure hovefly into the labellum, whose fruit set rate is 54.37%±6.08%, the fruits grow into sufficient young plants and most of them could live through the sexual reproduction stage. Sexual reproduction generates progeny many times over a long period suggesting this kind of reproductive mode is the main factor affecting numeric dynamics of a population. The species′ successful reproductive strategies and their impacts on numeric dynamics in spatial and age distribution indicate that the population development of C. lentiginosum corresponds to its biological characteristics. Discontinuity and narrowness of growing space in the habitat are the main factors restricting population development, however, at present, the species does not need, nor will it prosper from, ex-situ conservation.
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