Phenology of tropical tree species – environmental cues, molecular mechanisms, and consequences for plant-animal interactions

物候学包括开花、结果、发芽和叶片衰老对树木在当地栖息地的适应性至关重要。温带树种利用温度或白昼长度等线索来确定这些物候转变的时间。对于温带地区，已经有了一个很好的知识基础，包括环境线索、分子基础和物候转变对植物-动物相互作用的影响，而相比之下，热带树木的知识仍然很少。许多热带树木种群表现出规律和同步的物候转变，但它们所使用的环境线索调节物候转变存在不确定性。此外，我们实际上对基因的潜在调控一无所知，也不知道物候变化对热带树木生理学和植物与动物相互作用的影响。因此，研究热带树木物候学需要综合考虑树木物候学监测、研究基因表达的分子方法和研究植物-动物相互作用的生态学方法。这项研究将在厄瓜多尔南部的山地湿润森林和季节性干燥热带森林进行，在Estacíon Científica San Francísco和Estacíon Científica Laipuna研究站进行。在这里，以前和正在进行的项目的可用数据以及对气候和碳通量等重要参数的持续测量为实现树木物候研究提供了理想的基础。在这个项目中，我们将同时监测四种树种的物候转变、基因表达变化、茎径变化、冠层光学特性，并将其与碳通量和气候参数联系起来。因此，该项目将提供关于物候转变是如何触发的，哪些基因调控网络参与物候转变，以及这些如何影响植物生长和碳封存的见解。此外，我将在物候转变的光下研究树木及其互惠和拮抗伙伴的相互依赖性。首先，我将研究传粉者组合、花粉介导的基因流、种子集和发芽率。其次，我将调查相关的食草动物组合和食草率随时间的变化。总的来说，这个项目将对未来预测气候变化对山地雨林的影响做出重要贡献。

Phenology including flowering, fruiting, bud burst, and leaf senescence is vital for the fitness of trees in their local habitats. Temperate tree species use cues such as temperature or day length to time these phenological transitions. For temperate regions, there is already a good base of knowledge on the environmental cues, the molecular basis and the consequence of phenological transitions for structuring plant-animal interactions, while, in contrast, such knowledge for tropical trees is still scarce. Many tropical tree populations exhibit regular and synchronized phenological transitions but there is uncertainty about the environmental cues used by them to regulate phenological transitions. Furthermore, we know virtually nothing about the underlying regulation of genes, or about the effects of phenological transitions on tree physiology and plant-animal interactions in the tropics. Investigating tropical tree phenology thus requires an integrative approach that takes into account the monitoring of tree phenology, molecular methods to study gene expression, and ecological approaches to study plant-animal interactions.This study will be carried out in the montane humid forests and the seasonally dry tropical forest of Southern Ecuador, at the research stations Estacíon Científica San Francísco and Estacíon Científica Laipuna. Here, available data from previous and ongoing projects and a continuous measurement of important parameters such as climate and carbon flux provide an ideal basis for realizing a study on tree phenology. During this project we will simultaneously monitor phenological transitions, changes of gene expression, stem diameter variation, optical properties of canopies in four tree species and link this to carbon fluxes and climatic parameters. Thereby, this project will provide insights on how phenological transitions are triggered, which gene regulatory networks are involved in phenological transitions, and how these influence plant growth and carbon sequestration. Further, I will study the interdependencies of trees and their mutualistic and antagonistic partners in the light of phenological transitions. First, I will investigate pollinator assemblages, pollen-mediated gene flow, seed set, and germination rates. Second, I will investigate associated herbivore assemblages and rates of herbivory over time. Overall, this project will make important contributions to future predictions of the impact of climate change on montane rainforests.