长白山泥炭地苔藓植物生态位分化的竞争-化感-防御权衡机制

Plants often face the dilemma how to allocate resources among three aspects, resource competition, allelopathetic exclusion and stress resistance, and it is a new scientific question in ecology and biogeography whether niche differentiation and co-existence among plants depend on the trade-off among the three aspects. In this project, we plan to chose 3 Sphagnum species, with clear niche differentiation, diverse types of life-history strategies, obvious allelopathy, as study species to try to carry out a study on mechanism of the plant niche differentiation. The study contents in detail are: 1) the effect of stresses and neighors in simulated environments on resource competition and allelopathy in plants; 2) the effect of resource competition and allelopathy on niche differentiation between competitors; 3) the effect of allelopathy and chemical defense on niche differentiation between competitiors; 4) the dynamics of resource competition, allelopathy and chemical defense and their effect on niche differentiation between competitor and stress-tolerantor. In this project, it is quite possible to accutatedly separate allelopathy from allelopathy, obtain experimental proofs of the trade-off of compeition-allelopathy-defense in peatland bryophytes and discover the chemical ecology mechanism of the niche differentiation and fine scale co-existence of plants with different life history strategies. With the project, we are eager to to supply a new thought for plant-plant interaction study and make a contribution to the development of co-existence theory in plant ecology and plant geography.

植物经常面临在竞争资源、化感排他以及抵御胁迫间分配资源的困境，三者的权衡是否决定植物生态位分化与共存属于生态学和生物地理学崭新的科学问题。本项目拟选择生态位分化明显、生活史策略多样、化感作用突出的3种泥炭藓植物为主要实验物种，尝试开展植物生态位分化的机理研究。具体研究内容包括：1）模拟环境中的环境胁迫和邻体对植物资源竞争和化感作用的影响；2）资源竞争与化感作用对竞争策略者生态位分化的影响；3）化感作用和化学防御对竞争策略者生态位分化的影响；4）资源竞争、化感作用和化学防御的动态及其对竞争和耐受策略者生态位分化的影响。项目有望准确分离资源竞争和化感作用，获得泥炭地苔藓植物存在竞争-化感-防御权衡的实验证据，揭示不同生活史策略者生态位分化及小尺度共存的化学生态学机制。本研究可为植物相互作用研究提供新思路，为植物生态学和植物地理学的植物共存理论发展做出贡献。

植物经常面临在竞争资源、化感排他以及抵御胁迫间分配资源的困境，三者的两两权衡是否决定植物生态位分化与共存属于生态学和生物地理学崭新的科学问题。本项目选择生态位分化明显、生活史策略多样、化感作用突出的 3 种泥炭藓植物为主要实验物种，尝试开展了植物生态位分化的机理研究。研究结果显示：泥炭地苔藓植物可以通过改变非结构性碳水化合物、总酚含量等对干旱、邻体、昆虫采食等做出响应。泥炭藓存在生长-化感作用的权衡、生长（资源竞争）-防御的权衡以及防御-繁殖的权衡。藓丘种难以在丘间生长的原因是其耐水淹能力的限制以及丘间种化感抑制作用导致的；丘间种难分布于藓丘生境是因其受到藓丘种强烈的水分竞争抑制。在泥炭藓的种间相互作用特别是化感作用不仅仅作用于植物体，还会影响植物有性繁殖体的活力和萌发力，对植物种群的更新乃至植物分布格局也发挥着重要作用。本项目研究表明，植物间的资源竞争、化感作用和化学防御共同影响泥炭地苔藓植物的生态未分化。未来有关植被格局和多样共存研究中，应对外界环境胁迫、扰动如动物采食、践踏等条件下，植物的化感作用、化学防御等予以重视。