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  1. Abstract

    In clonal plants, persistent rhizomes can serve multiple purposes, including resource storage, modulation of heterogeneous resource distributions, maintenance of bud banks and promotion of recovery from disturbance. Clonal plants are commonly long‐lived and, in temperate zones, often exhibit organ preformation. Thus, investigations of how the timing of disturbance to the rhizome affects plant performance must occur over multiple growing seasons, but these types of studies are rare.

    We conducted a field experiment to examine how the persistent rhizome supports the existing shoot, new ramet production and recovery from damage using mayapplePodophyllum peltatum(Berberidaceae), a common herbaceous perennial of low‐light forest understories in Eastern North America. Mayapple maintains a long‐lived rhizome and exhibits a developmentally programmed seasonal pattern of resource transport and new ramet initiation. We varied both the position and timing of rhizome severing in rhizome systems with terminal sexual or vegetative shoots, and tracked plants for 2 years following severing.

    The location and timing of severing affected both plant persistence (production of new shoots) and performance (leaf area), with effects differing for new shoots that developed at the front versus the back of the rhizome system. Across years, severing location and past years’ shoot size influenced plant persistence and performance, while the effect of timing of severing diminished. Initial sexual status had little effect on rhizome system response that was not accounted for by initial leaf area. Severing generally led to the establishment of two independent rhizome systems. Relative to unmanipulated control systems, these two systems had more total leaf area, but less average leaf area per system.

    Synthesis. Our results point to the rhizome as a resource integrator that affects plant responses to disturbance immediately following damage and in subsequent growing seasons. Rhizome bud age and/or subtending rhizome size, and developmental programme influence responses to disturbance. While the effects of experimental disturbance on plant performance decreased 2 years after disturbance, further long‐term investigation is needed to fully understand the demographic consequences of damage to persistent rhizomes.

    A freePlain Language Summarycan be found within the Supporting Information of this article.

     
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  2. Abstract

    Determining how pollinators visit plants vs. how they carry and transfer pollen is an ongoing project in pollination ecology. The current tools for identifying the pollens that bees carry have different strengths and weaknesses when used for ecological inference. In this study we use three methods to better understand a system of congeneric, coflowering plants in the genusClarkiaand their bee pollinators: observations of plant–pollinator contact in the field, and two different molecular methods to estimate the relative abundance of eachClarkiapollen in samples collected from pollinators. We use these methods to investigate if observations of plant–pollinator contact in the field correspond to the pollen bees carry; if individual bees carryClarkiapollens in predictable ways, based on previous knowledge of their foraging behaviors; and how the three approaches differ for understanding plant–pollinator interactions. We find that observations of plant–pollinator contact are generally predictive of the pollens that bees carry while foraging, and network topologies using the three different methods are statistically indistinguishable from each other. Results from molecular pollen analysis also show that while bees can carry multiple species ofClarkiaat the same time, they often carry one species of pollen. Our work contributes to the growing body of literature aimed at resolving how pollinators use floral resources. We suggest our novel relative amplicon quantification method as another tool in the developing molecular ecology and pollination biology toolbox.

     
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