Disentangling root system responses to neighbours: identification of novel root behavioural strategies
Disentangling root system responses to neighbours: identification of novel root behavioural strategies
复制标题
DOI：
10.1093/aobpla/plv059
复制
发表时间：
2015-01-01
期刊：
影响因子：
2.9
通讯作者：
Cahill, James F., Jr.
中科院分区：
文献类型：
--
作者：
Belter, Pamela R.;Cahill, James F., Jr.
植物生活在社会环境中，邻居之间的相互作用是生活中无处不在的方面。尽管其中许多相互作用发生在土壤中，但我们对植物如何改变根的生长以及土壤对邻居的反应模式的了解有限。这与关于动物对社会环境变化的行为反应的丰富文献形成了鲜明对比。对于植物来说，改变土壤占用模式的根系行为变化可以影响邻里大小和对土壤资源的竞争频率或强度；这些问题对于理解共存和群落聚集至关重要。在这里，我们报告了一项大型的比较研究，其中20个物种的个体在有和没有两个相邻物种的情况下生长。通过重复的根系可视化和分析，我们量化了许多假定的根系行为，包括每个物种改变根系生长方面的程度(例如，根宽、根长等)。作为对邻居的回应。在所有物种中，对邻居没有一致的行为反应(即没有根过度繁殖或回避的一般趋势)。然而，有一个实质性的种间差异表明，在20个物种之间的行为差异是连续的。多变量分析揭示了两种新的和主要的根系行为策略：(I)尺寸敏感性，即焦点植物对邻居的存在做出反应，缩小其总体根系尺寸；(Ii)位置敏感性，焦点植物根据邻居的存在调整其根系的水平和垂直位置。其中，规模敏感度代表了人们通常认为的对竞争对手的反应--增长放缓。然而，在植物竞争的经典模型和概念中没有解释位置敏感性，尽管它得到了植物行为生态学最近的工作的支持。我们认为，这些不同的策略可能会对工厂在强大竞争对手面前持续存在的能力产生重要影响，位置敏感性可能是促进竞争容忍和共存的关键行为策略。
Plants live in a social environment, with interactions among neighbours a ubiquitous aspect of life. Though many of these interactions occur in the soil, our understanding of how plants alter root growth and the patterns of soil occupancy in response to neighbours is limited. This is in contrast to a rich literature on the animal behavioural responses to changes in the social environment. For plants, root behavioural changes that alter soil occupancy patterns can influence neighbourhood size and the frequency or intensity of competition for soil resources; issues of fundamental importance to understanding coexistence and community assembly. Here we report a large comparative study in which individuals of 20 species were grown with and without each of two neighbour species. Through repeated root visualization and analyses, we quantified many putative root behaviours, including the extent to which each species altered aspects of root system growth (e.g. rooting breadth, root length, etc.) in response to neighbours. Across all species, there was no consistent behavioural response to neighbours (i.e. no general tendencies towards root over-proliferation nor avoidance). However, there was a substantial interspecific variation showing a continuum of behavioural variation among the 20 species. Multivariate analyses revealed two novel and predominant root behavioural strategies: (i) size-sensitivity, in which focal plants reduced their overall root system size in response to the presence of neighbours, and (ii) location-sensitivity, where focal plants adjusted the horizontal and vertical placement of their roots in response to neighbours. Of these, size-sensitivity represents the commonly assumed response to competitive encounters-reduced growth. However, location sensitivity is not accounted for in classic models and concepts of plant competition, though it is supported from recent work in plant behavioural ecology. We suggest that these different strategies could have important implications for the ability of a plant to persist in the face of strong competitors, and that location sensitivity may be a critical behavioural strategy promoting competitive tolerance and coexistence.