多年生植物年度结实的资源获取、投放和分配策略

Constrained by limited resources, plants usually show trade-offs among various functions or performances during reproduction, related with which, life-history traits, breeding and mating systems have always been hot research topics in plant reproductive ecology. Despite its popularity, the default precondition of “resource limitation” has seldom been questioned or experimentally tested. In fact, plants bear the ability to alter its resource acquisition rate, amount of investment, and allocation pattern during different stages in reproduction. Consequently, the resource level can be enhanced or cut at certain developmental time or part within plants, thus making plants dynamically respond to changes in mating environment and maximize the utilization of resources. Such resource policy seems to be an adaptation to environmental uncertainty, especially by perennial flowering plants. This project plans to use an aquatic perennial plant, Sagittaria trifolia, to study whether the resource acquisition, investment and allocation patterns alter with varying fruiting regimes. We aim to control the quantity and quality of fruits and measure the rates of carbon and nitrogen assimilation, the performance of fruits and its relation to storage organ and future reproduction, and the relative quantity, quality and interaction of selfing/outcrossing fruits within inflorescences under each scenario. This research will elucidate the resource policy by Sagittaria trifolia in annual reproduction, help uncover the patterns of “Demand-driven Resource Acquisition, Investment, and Allocation”, and hierarchically explore the border of resources at the levels of plant, fruit, and seed.

受有限资源的制约，植物繁殖过程中的各种功能或表现之间往往存在权衡，与之相关的生活史特征、繁育或交配系统一直以来都是植物繁殖生态学研究的焦点与热点。尽管研究众多，“资源有限性”这一默认前提却很少被质疑。事实上，植物在繁殖的各个阶段均有可能根据结实的需求改变资源的获取速率、投放水平以及分配方案，使得某段时间或空间内的资源提升或下降，从而动态的应变交配环境的改变、最大化利用资源。这一资源策略应该是多年生有花植物对环境不确定性的适应。本项目选取多年生水生植物野慈姑作为实验材料，从结实的数量和质量入手开展两项控制处理，检测植株在不同繁殖需求下的碳、氮同化速率，果实表现和营养器官或来年繁殖之间的关系，以及花序内自交或异交果实的相对表现和相互影响。以期阐明野慈姑年度结实的资源策略，揭示资源“按需获取、投放和分配”的表现式样，从植株、果实到种子多层次的探索资源的边界。

受有限资源的制约，植物繁殖过程中的各种功能或表现之间往往存在权衡，与之相关的生活史特征、繁育或交配系统一直以来都是植物繁殖生态学研究的焦点与热点。尽管研究众多，但“资源有限性”这一默认前提却很少被质疑。事实上，植物在繁殖的各个阶段均有可能根据结实的需求改变资源的获取速率、投放水平以及分配方案，使得某段时间或空间内的资源提升或下降，从而动态的应变交配环境的改变、最大化利用资源。这一资源策略应该是多年生有花植物对环境不确定性的适应。本项目选取多年生水生植物野慈姑作为实验材料，从结实的数量和质量入手开展两项控制处理，检测植株在不同繁殖需求下的资源获取、投放和分配策略。结果如下：（1）野慈姑在不同的结实需求下植株的碳、氮同化速率并无差异，无论结实的需求如何，植株的整个生命阶段都是以最大速率合成有机物，进行碳、氮等营养物质的积累。（2）野慈姑现阶段的繁殖需求会影响其来年的繁殖表现，具体体现在有性与无性繁殖之间的权衡上。（3）无论是在果实数量还是质量需求控制下，花序内的果实之间都出现了资源的按需分配现象，果实之间通过竞争获取更多的资源，且具体表现为通过种子大小的调整来提高繁殖适合度。（4）野慈姑花序内部表现出果实（或花）由基部到顶部逐渐下降的繁殖差异，该表现不由顺次花朵的交配变化造成，而是由花序内部果实之间基于位置的资源竞争所导致，且轮内竞争大于轮间。

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