In seedling-based reforestation operations, seed source is known to be an influential variable affecting outplanting success. Adaptive variation among seed sources may also be an important factor in the effectiveness of standardized nursery protocols for seedling production. Particularly for wide-ranging species, regional optimizations of nursery protocols may be necessary to ensure consistent production of quality seedling stock. Quaking aspen (Populus tremuloides Michx.) is one such species, possessing the broadest distribution of any tree in North America. However, research on nursery protocols specific to aspen has focused on seed sources from a limited region in western boreal Canada. A well-established protocol shown to be effective for these boreal aspen uses a shoot growth inhibitor designed to maximize desirable seedling quality traits for outplanting success. We used this protocol on seeds sourced from two different regions in the southwestern portion of the species range (Utah and New Mexico, USA) and compared their response in the same nursery environment to that of a seedlot from Alberta, Canada to determine whether this protocol is also applicable for these very different regions. Seedlings from Utah and New Mexico differed significantly in their response to the protocol from the Alberta source, developing smaller root-to-stem ratios and sequestering less carbohydrate and nutrient reserves. Seedlings from Utah and New Mexico sources also differed from each other, with New Mexico seedlings growing larger according to all metrics. These results indicate that aspen nursery protocols will benefit from regional modification in order to optimize seedling stock quality and trait consistency.

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对已建立的苗圃规程的白杨（白杨）幼苗的区域差异

在基于幼苗的重新造林操作中，已知种子来源是影响移栽成功的有影响力的变量。种子来源之间的适应性变化也可能是标准化苗圃规程生产苗木有效性的重要因素。特别是对于广泛的物种，可能有必要对苗圃规程进行区域优化，以确保稳定生产优质苗木。地震白杨（杨）Michx。）就是其中一种，在北美地区拥有任何树木中分布最广的物种。但是，针对特定于白杨的育苗规程的研究集中于加拿大西部北方有限地区的种子来源。一种成熟的方案显示对这些北方白杨有效，它使用了一种芽生长抑制剂，旨在最大程度地提高期望的幼苗品质性状，从而成功实现移栽。我们对来自物种范围西南部分（美国犹他州和新墨西哥州）两个不同地区的种子使用了该方案，并将它们在相同育苗环境中的反应与加拿大艾伯塔省的一个种子场的反应进行了比较，以确定该方案是否也适用于这些截然不同的地区。来自犹他州和新墨西哥州的幼苗对亚伯达省来源的试验方案的反应差异很大，根茎比更小，而碳水化合物和营养素的储备更少。来自犹他州和新墨西哥州的幼苗也有所不同，根据所有指标，新墨西哥州的幼苗长得更大。这些结果表明，白杨育苗规程将受益于区域改良，以优化苗木质量和性状一致性。