荒漠两季开花植物生殖适应对策——多枝柽柳繁育特征的时空分异规律及进化意义

The reproductive ecology research of special reproductive phenomenon in extreme desert ecosystem is the important way to find out the co-evolution problem between life history tactics and environmental factors. Tamarix ramosissima is the widespread species in Xinjiang desert ecosystem, which has spring and summer flowering period. From the evolutionary ecological angel,the spatial and temporal differentiation of reproductive traits under bi-seasonal flowering period is the key to understand the reproductive adaptive tactic.Four aspects will be examined by a series of wild investigation, green house experiment and laboratory analysis methods in three populations in different latitudinal zones: ①The reproductive phenology and the response to ecological factors;②The interaction machanism between floral traits and pollinators; ③ The seed dispersal trait and spatial pattern;④The seed germination behavior and relationship of ecological adaptability and germination trait. We can not only further analysis the influence on reproductive ecological adaptability of phenology to geographical environment under different habitat zones, but also can explore the adjust mechanism of floral traits on pollination adaptation. Moreover, the ecological function differentiation of seeds from spring and summer flowering period will be disscussed. Then, we can understand the ecological evolutionary significance of this special bi-seasonal traits.The new theory is expected on the "reproductive ecology of bi-seasonal species" research field.Besides,the results will provide theory evidence and case analysis for the understanding of multiple adaptive tactics of species under extreme desert environment.

极端生态系统中，特殊生殖现象的繁殖生态学研究是解读物种生活史对策与环境因子协同进化问题的重要途径。多枝柽柳是新疆荒漠生态系统中的广布种。该种具有春、夏两季开花的生殖表现。深入理解该种两季花期繁殖特征的时空分异规律是从进化生态学角度理解该种生殖适应对策的关键。本研究拟通过野外调查、温室试验及室内分析等方法，分别对不同纬度自然种群的春、夏花期进行以下研究：①生殖物候特征及对生态因子的响应；②花部特征和传粉者的相互作用机制；③种子扩散特征及空间格局；④种子萌发行为与生态适应性的关系。通过上述内容深入分析不同生境的地理环境对物候生态适应的影响，探讨花部特征对传粉适应过程的时空调整机制，揭示不同花期种子的生态功能分异，进而明晰该种两季开花表现的生态进化含义。研究有望在"两季开花植物繁殖生态学"研究领域产生新的理论认识及突破，并为深入理解荒漠极端生境下植物的多样化适应对策提供理论依据及个例分析。

极端生态系统中，特殊生殖现象的繁殖生态学研究是解读物种生活史对策与环境因子协同进化问题的重要途径。多枝柽柳是柽柳科柽柳属植物，为新疆荒漠生态系统中的广布种，具有春、夏两季开花的独特生殖表现。通过对其两季花期繁育特征的对比研究，发现：多枝柽柳春花期为5月下旬至6月上旬，表现为“集中开花模式”，夏花期为6月中旬至9月上旬，表现为“持续开花模式”；两季花期间的花部形态特征和数量特征之间多不存在显著差异，但春花期花药散粉时间显著长于夏花期；两季花期传粉昆虫日访花频率曲线均呈双峰型，春花期有效传粉昆虫为黄环粗股蚜蝇、短腹管蚜蝇和意大利蜜蜂，夏花期有效传粉昆虫为意大利蜜蜂，春花期昆虫访花频率显著高于夏花期；交配系统表现为：不存在无融合生殖、自交亲和，存在自交衰退，倾向异交；春花期主要通过蜂媒传粉实现结实，夏花期则主要依靠自交保障生殖成功，此种交配格局是在异质传粉环境下最有效得提高结实质量和保证生殖成功率的有效策略；春花期种子的千粒重、长度与宽度均显著高于夏花期，温变周期对多枝柽柳春花期种子无显著影响，夏花期种子的萌发率与萌发速度随着温度的下降而下降；春花期种子的耐盐萌发率高于夏花期。相关成果已发表学术论文5篇，投稿在审2篇，部分结果还在整理中。研究结果为我国两季开花植物繁殖生态学领域提供了基础数据。