基于能量学的外来红树植物速生机制与入侵性研究

As a new perspective in biological invasion researches, the energetics of invasive plants could explain their fast-growing mechanisms. In mangrove forests, different reproduction types including viviparous and recalcitrant seeds implied different energetic dynamics. As a non-native plant, Sonneratia aptetala became a major forested mangrove species in mangrove restoration in China because of its fast growing and well adaptation. Reproduced by small recalcitrant seeds and with low energy from mother trees, S. apetala out-competed many native viviparous mangrove species in the stage from seedling to tree. Due to the uncertainty to its invasive potential, it is an urgent need to discover the mechanisms behind its fast-growing. .Integrated the energy-used properties of invasive plants and energy budget throughout the life history of mangrove species, we hypothesis that there are some energy-saving strategies contributing to the fast-growing and invasiveness of S. apetala. Field investigations on forest structures, litterfall trapping and phenological observations will be conducted in the field of Dongzhaigang mangroves in Hainan Province. We want to construct sets of continual physiological measurements and energy budgets during three typical stages, which are survival, growth and reproduction, along the early life from seeds to little trees, by comparing S. apetala with native viviparous mangrove species in greenhouse. Combined these parts of evidences, we aim to seek out the energetics implied in its fast-growing performance and the probable disturbance to the niche patterns of native mangrove forests. We hope the results of these studies would provide useful information to improving our understanding on the invasiveness of this non-native species, and enable the policy makers and forest managers to prepare appropriated strategies to manage the invasion.

能量学是入侵植物研究的新视角；胎生与非胎生两种繁殖方式的红树植物在生活史中有特殊的能量动态。由于速生和适应性好，无瓣海桑自引入我国后一直被用于红树林造林，其入侵潜力也备受关注。作为非胎生种，无瓣海桑的种子小、从母体获得的能量远低于胎生胚轴；但其生长速率远高于胎生物种。整合了入侵植物能量利用率和红树植物生活史能量收支，本研究围绕无瓣海桑维持速生的能量动态这一关键问题，结合物候观测和温室生活史的跟踪研究，应用气体通量、树干液流和稳定同位素等技术，比较胎生和非胎生红树植物个体的存活、生长和繁殖三个关键期的能量收支动态，旨在揭示无瓣海桑速生的能量学蕴含。研究结果将为无瓣海桑入侵潜力的准确评估和我国红树林湿地恢复实践工作提供理论依据。

胎生与非胎生两种繁殖方式的红树植物在生活史中有特殊的能量动态。无瓣海桑自引入我国后一直被用于红树林造林，其入侵潜力也备受关注。作为非胎生种，无瓣海桑的种子小、从母体获得的能量远低于胎生胚轴；但其生长速率远高于胎生物种。基于入侵植物能量利用率和红树植物生活史能量收支，本研究围绕无瓣海桑维持速生的能量动态这一关键问题，结合野外定位、物候观测和温室生活史的跟踪研究，应用气体通量、树干液流和稳定同位素等技术，比较胎生和非胎生红树植物个体的存活、生长和繁殖三个关键期的能量收支动态，揭示外来红树植物的速生机制及其能量学：a) 无瓣海桑通过在繁殖阶段加大对繁殖体能量的投入，提高种子数量进而增加幼苗数量；b) 无瓣海桑和拉关木幼苗期速生机制主要依靠在种子萌发后大量能量分配在叶片和根系生长中，进而提高固碳能力和生长速率；c) 盐度和光照对无瓣海桑和拉关木幼苗生长具有协同作用，随着植株的长高，幼苗生长和能量固定量显著增高，进而增加生态位竞争优势；d) 高盐开阔地或林冠下区域是外来种幼苗与乡土红树植物发生生态位竞争的主要区域，也是防控无瓣海桑、拉关木发生生物入侵的关键区域。研究结果将为无瓣海桑入侵潜力的准确评估和我国红树林湿地恢复实践工作提供理论依据。