青藏高原东部高寒草甸植物开花物候研究

发布时间：2018-11-25 22:43

【摘要】：物候学具有悠久的历史,随着近些年来大家对全球气候变化的关注,作为非常适合的研究全球气候变化方法的植物物候也逐渐成为了学者研究的热点。相对于大部分生态系统而言,高寒生态系统无疑面临着更大的气候变化压力。尽管如此,关于高寒植物物候的较为系统、全面的研究还是偏少的。目前大家较为认可的影响植物开花物候因素包括:非生物因素(日长、温度、降水量等)、生物因素(传粉者、种子传播者、采食者等)、物种间谱系发育关系及植物自身功能特征。然而大部分相关研究关注的问题都较为单一,更少有考虑这些因素对于植物开花物候的交互影响。我们分别用2008年至2012年5年高寒草甸群落与沼泽化草甸群落植物开花物候数据,2008年至2014年7年高寒草甸群落植物开花物候数据与分子谱系发育树、功能特征发育树及气象数据从不同角度,运用广义线性模型、混合效应模型、多元谱系发育特征向量回归分析(phylogenetic eigenvector regressions,PVR)、零模型及谱系发育信号计算对青藏高原东部高寒草甸及沼泽化草甸植物群落开花物候进行了详细的分析。我们得出的主要结论如下:1.高寒植物开花物候(包括初蕾期与初果期)具有谱系发育保守性:即亲缘关系相近物种更倾向于在相似时间进行有性繁殖。在不同高寒植物群落,不同年份及不同建树方法下,该结果依然一致。2.日长是驱动高寒草甸与沼泽化草甸植物群落开花物候的最主要因素,温度次之,降水量与高寒植物群落物候无显著相关性。3.气象因子与物种间谱系发育关系共同决定了高寒植物群落开花物候格局:气象因子显著影响植物群落中处于开花期的物种数,而物种开花时间(顺序)则与物种间谱系发育关系相关。4.亲缘关系相近物种倾向于在相似的日长与温度下进行有性繁殖。因此植物开花物候谱系发育保守性的关键很可能在于某个时间段内的外界环境因素,而不是时间本身。5.我们用2008年至2014年7年青藏高原东部高寒草甸植物群落开花物候数据(初花期,开花峰期与开花持续期),分子谱系发育树及功能特征发育树提出并用混合线性模型验证了植物群落影响假说:在群落内部物种间竞争作用较强的情况下,植物开花物候可能会延迟;反之,在群落内部物种间竞争作用较弱或正相互作用较强的情况下,植物开花物候可能会相应提前。6.该假说在物种水平,科水平与群落水平上均成立;表明高寒植物开花物候可能受到了稳定持续而普遍的自然选择。7.不同分类水平上(生活型、传粉方式、植物高度、植株生物量及开花峰期),植物开花物候对于植物群落的不同响应反映了其生活策略的差异。
[Abstract]:Phenology has a long history. With the attention paid to global climate change in recent years, plant phenology, as a very suitable method to study global climate change, has gradually become a hot spot of scholars. Compared with most ecosystems, alpine ecosystems undoubtedly face greater pressure of climate change. However, systematic studies on alpine plant phenology are still relatively rare. Some of the most recognized factors affecting flowering phenology include abiotic factors (day length, temperature, precipitation, etc.), biological factors (pollinators, seed disseminators, eaters, etc.), Phylogenetic relationships among species and the functional characteristics of plants themselves. However, most of the related studies focus on a single problem, less consider these factors on plant flowering phenology interaction. We used flowering phenological data of alpine meadow community and marshland meadow community from 2008 to 2012, and plant flowering phenological data and molecular phylogenetic tree of alpine meadow community from 2008 to 2014. From different angles, the functional feature development tree and meteorological data are analyzed by generalized linear model, mixed effect model and multivariate lineage characteristic vector regression analysis (phylogenetic eigenvector regressions,PVR). The flowering phenology of alpine meadow and swamp meadow in eastern Qinghai-Xizang Plateau was analyzed in detail by zero-model and pedigree development signal calculation. Our main conclusions are as follows: 1. The flowering phenology of alpine plants (including early bud and early fruiting stage) is conserved by genealogy, that is to say, similar species tend to propagate sexually at similar times. Under different alpine plant communities, different years and different tree building methods, the results are still consistent. 2. Day length was the main factor driving flowering phenology of alpine meadow and marshland meadow, followed by temperature, and precipitation had no significant correlation with alpine plant community phenology. 3. The relationship between meteorological factors and pedigree development among species determined the flowering phenological pattern of alpine plant community. Meteorological factors significantly affected the number of species in flowering period of plant community. The flowering time (order) of species was related to the phylogenetic relationship between species. 4. 4. Closely related species tend to reproduce sexually at similar day length and temperature. Therefore, the key to the development conservatism of plant flowering phenology is probably due to the external environmental factors within a certain period of time, rather than the time itself. 5. 5. From 2008 to 2014, we used flowering phenological data of alpine meadow plant communities in eastern Qinghai-Xizang Plateau (early flowering period, flowering peak period and flowering duration). Molecular phylogenetic tree and functional developmental tree were proposed and the mixed linear model was used to verify the hypothesis of plant community influence: under the condition of strong competition among species within the community, plant flowering phenology might be delayed; On the other hand, under the condition of weak competition among species within the community or strong positive interaction, flowering phenology of plants may advance by 6. 6. This hypothesis is true at species level, family level and community level, indicating that flowering phenology of alpine plants may be subjected to stable and persistent natural selection. At different classification levels (life form, pollination mode, plant height, plant biomass and flowering peak period), the different responses of plant flowering phenology to plant community reflected the difference of their living strategies.
【学位授予单位】：兰州大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：Q948

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