【作者】 张昊；

【导师】 李俊清；

【作者基本信息】 北京林业大学 ， 生态学， 2006， 博士

【摘要】 荒漠(desert)以其分布范围广泛、覆盖面积巨大、环境极端严酷和生态系统极其脆弱以及对一定区域乃至全球环境的深刻影响等特点,而占据十分特殊地位。荒漠绿洲(oasis)既是整个荒漠生态系统的最重要组成部分,也是干旱区最为敏感的关键区域,其兴衰深刻影响着毗邻地区及更广泛的区域。以胡杨(Populus euphratica Oliv.)为建群种所组成的荒漠河岸林,是在荒漠干旱气候影响下依托内河流形成的非地带性植被,是额济纳绿洲植被的主体。由于胡杨分布区域的经济相对落后以及对胡杨林维持荒漠地区生态平衡的功能认识不足,胡杨林遭受严重破坏,分布面积急剧缩小,衰退现象十分严重。繁殖(reproduction)作为生物产生新个体的行为或过程,是生物在整个生活史进程中至关重要的必要环节,是生物繁衍后代延续种族最基本的行为,种群形成、发展和进化的核心问题之一。作为生活史中主要特征的繁殖对策(reproductive strategy)是指植物在其生活史过程中,通过最佳的资源分配格局,以其特有的繁殖属性从时空上适应环境,提高植物适合度的自组织过程。其适应的对象是生存环境,最终目标是物种的持续生存和繁衍。上世纪九十年代以来,繁殖对策、生存对策、行为与种群密度周期之间的关系和行为对策的进化稳定性等成为国际上繁殖生态学和行为生态学研究的主要领域。本文以额济纳绿洲极端干旱条件下荒漠河岸林中主要建群植物胡杨为研究对象,以恩格勒的植物分类系统、植被分布规律和种群生态对策等为理论基础,应用物候学和繁殖生态学的原理和研究方法,以种群-生境关系为主线,从胡杨种群物候、繁殖节律、及有性和无性繁殖特性等进行了一定深度较系统的研究。揭示了胡杨种群物候节律特征、胡杨种群在不同水平上的开花时间异质性等繁殖节律特征和地上分枝建构模式及繁殖器官数量特征;初步探讨了胡杨种群繁殖节律与水热条件的相互关系;总结了胡杨种群种子库的形成机制和种子安全萌发生境的特征和种子散布期的选择机制;分析了无性繁殖特征及其与生境的关系和现阶段胡杨种群繁殖状况。在此基础上,总结归纳了胡杨种群的繁殖对策和生活史对策。主要研究结果如下:额济纳绿洲分布的胡杨种群拥有适应当地的生境条件、有规律地交替进行的物候期。雌雄株的小花和花序等繁殖器官的结构、形态和数量及地上部分分枝的模式等方面的特征,可较好地保障风媒传粉和受精过程及种子散布的顺利实现;繁殖年龄等方更多还原

【Abstract】 Desert occupies a special position in the Earth global ecosystem and has a great influence on the global environment. It occupies a great area in the world; its environmental condition is extremely serious and frail. Oasis is not only the most important part of desert ecosystem, also the most sensitive region. The fate of oasis has a significant impact on the neighbor regions and even to a larger extent. Influenced by desert arid climate, desert riparian forest made up by Populus euphratica Oliv. is non-zonal vegetation as well as the main part of the Ejina oasis of Inner Mongolia. Due to the undeveloped regional economy and the lack of understanding on the function of Populus forest on maintaining eco-balance in desert region, Populus euphratica forest suffered havoc, its distribution area reduced sharply, and the withering phenomenon is very serious.As the behavior or process of generating new units, reproduction is an important phase in the whole biological life history, the most basic behavior of regeneration. It is also one of the key issues in the population forming, developing and evolution. Being an important trait of life history, reproductive strategy is a self-organizing process in which plants adapt their habitat environment through the best resource distribution pattern. The adaptive object of reproductive strategy is environment; its final aim is the sustainable survival and reproduction of species. From 1990’s to the present, reproductive strategy, life history, the relationship between behavior and the cycle of population density as well as evolutionary stability of behavior strategy become the main research field in the reproduction ecology and behavior ecology in the world.The object of this paper is Populus euphratica Oliv., which is the dominating species in desert riparian forest. Using the theory bases of floristic taxonomic system of Engler, the of vegetation distribution, and ecological strategy of population, as well as the principle and research methods of phenology and reproductive ecology, through the masterstroke of更多还原