Characterizing the recruitment nature of weed species

表征杂草物种的补充性质

• 批准号: RGPIN-2014-06088
• 负责人: VanAcker, Rene
• 金额: $ 2.19万
• 依托单位: University of Guelph
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=567585
• 关键词: Characterizing; recruitment; nature; weed; species

The core goal of my research program is to determine how and why weeds emerge when they do. The timing of seedling emergence is a prime determinant of plant species success and for weeds, the transition from seed to seedling represents a transition from the least to the most vulnerable life cycle stage. The relative timing (versus crop plants) and the success of weed seedling emergence also determines the competitiveness of weed infestations, the potential for weeds to escape management, and the quantity and quality of weed seeds left to form persistent seed banks. In addition, emergence timing is a key determinant of the geographic range of species and their invasive potential. Finally, time of emergence greatly impacts the ability of weed species (including crop plants that have escaped farmed fields) to survive in wild or semi-wild habitats including roadsides. The latter has implications for gene flow at the landscape scale and the effective segregation of genetically modified (GM) from non-GM crops. Despite its fundamental importance in these respects, our understanding of the mechanism of emergence timing remains poorly understood for most weed species. To-date in my program we have made some significant contributions in this area including clear demonstration that seed depth in soil is a fundamentally important driver of emergence timing, and that the suitability of emergence conditions can be determined to a great extent by seed depth. We have also shown that timing of flowering and seed shed can play a very significant role in determining what conditions seeds experience (including whether and to what extent they are buried) and that this, in turn, can determine timing of emergence. Most recently, using Canada fleabane, a facultative winter annual weed (able to emerge at an time of the year), we were the first to document an interaction of the effects of these factors (flowering and seed shed timing, and seed depth) on emergence timing. What is not clear is the extent to which these observations represent generalizations and to what extent the effects feed forward to impact population performance (and weediness) in future generations, and how this may influence our ability to manage weeds. Our approach over the next 5 years will be to look forward in the life cycle of weeds (flowering timing and seed shed) in order to gain insight looking backward (to seedling emergence and emergence timing) using facultative winter annual weeds as test species. This research will lead to a better understanding of the mechanisms driving weed emergence timing which in turn will provide insights to aid weed management, weed risk assessments and the effective segregation of GM and non-GM crops.

我的研究计划的核心目标是确定杂草是如何以及为什么出现的。幼苗出苗的时间是植物物种成功的主要决定因素，对于杂草来说，从种子到幼苗的过渡代表了从最脆弱的生命周期阶段到最脆弱的生命周期阶段的过渡。杂草幼苗的相对出苗时间（相对于作物植物）和出苗成功与否也决定了杂草侵害的竞争力、杂草逃脱管理的可能性，以及留下的杂草种子的数量和质量，以形成持久的种子库。此外，出现时间是物种地理范围和入侵潜力的关键决定因素。最后，出现的时间极大地影响了杂草物种（包括逃离农田的作物植物）在野生或半野生栖息地（包括路边）的生存能力。后者对景观尺度上的基因流动和转基因作物与非转基因作物的有效分离具有重要意义。尽管它在这些方面具有根本的重要性，但我们对大多数杂草物种的萌发时间机制的了解仍然很少。到目前为止，在我的项目中，我们在这一领域做出了一些重大贡献，包括清楚地证明土壤中的种子深度是发芽时间的重要驱动因素，并且在很大程度上由种子深度决定发芽条件的适宜性。我们还表明，开花和种子脱落的时间可以在决定种子经历的条件（包括它们是否和在多大程度上被埋）方面发挥非常重要的作用，而这反过来又可以决定发芽的时间。最近，我们使用加拿大fleabane，一种冬季一年生杂草（能够在一年中的某个时间出现），首次记录了这些因素（开花和种子棚时间以及种子深度）对出苗时间的相互作用。目前尚不清楚的是，这些观察结果在多大程度上代表了普遍性，在多大程度上影响了后代的种群表现（和杂草），以及这将如何影响我们管理杂草的能力。在接下来的5年里，我们的方法将是展望杂草的生命周期（开花时间和种子棚），以便以冬季一年生杂草为试验物种，回顾过去（幼苗出苗和出苗时间）。这项研究将有助于更好地了解杂草出现时间的机制，从而为杂草管理、杂草风险评估和有效区分转基因和非转基因作物提供见解。