不定根的产生以及对生物量的可塑性资源分配决定了加拿大中部沿海沙丘木本植物的耐埋性。
Adventitious root production and plastic resource allocation to biomass determine burial tolerance in woody plants from central Canadian coastal dunes.
作者信息
Dech Jeffery P, Maun M Anwar
机构信息
Department of Biology, The University of Western Ontario, London, ON, Canada.
出版信息
Ann Bot. 2006 Nov;98(5):1095-105. doi: 10.1093/aob/mcl196. Epub 2006 Oct 3.
BACKGROUND AND AIMS
Burial is a recurrent stress imposed upon plants of coastal dunes. Woody plants are buried on open coastal dunes and in forested areas behind active blowouts; however, little is known about the burial responses and adaptive traits of these species. The objectives of this study were: (a) to determine the growth and morphological responses to burial in sand of seven woody plant species native to central Canadian coastal dunes; and (b) to identify traits that determine burial tolerance in these species.
METHODS
Field experiments were conducted to determine the responses of each species to burial. Saplings were exposed to burial treatments of 0, 10, 25, 50 and 75 % of their height. Burial responses were evaluated based on regressions of total biomass, height, adventitious root production and percentage allocation to shoot, root and adventitious root biomass on percentage burial.
KEY RESULTS
Pinus strobus and Picea glauca lacked burial tolerance. In response to the burial gradient, these species showed a strong linear decline in total biomass, minimal adventitious root production that peaked at moderate levels (25-50 % burial) and no change in allocation to shoots vs. roots. The tolerant species Juniperus virginiana, Thuja occidentalis and Picea mariana showed a quadratic response to burial, with little change in biomass up to 50 % burial, but a large decline at 75 %. These species produced abundant adventitious roots up to 50 % burial, but did not alter allocation patterns over the range of burial levels. Populus balsamifera and Salix cordata were stimulated by burial. These species showed linear increases in biomass with increasing burial, produced copious adventitious roots across the gradient and showed a clear shift in allocation to vertical shoot growth and adventitious root production at the expense of the original roots under high burial conditions.
CONCLUSIONS
Adventitious root production and plastic resource allocation to biomass are adaptive traits of coastal dune woody plants in central Canada, and provide a basis for assessing burial tolerance in woody plants on coastal dunes throughout the world.
背景与目的
掩埋是海岸沙丘植物反复面临的一种胁迫。木本植物会在开阔的海岸沙丘以及活跃风蚀坑后方的林区被掩埋；然而，对于这些物种的掩埋响应及适应性状却知之甚少。本研究的目的是：(a) 确定加拿大中部海岸沙丘原生的七种木本植物物种对沙埋的生长和形态响应；(b) 识别决定这些物种掩埋耐受性的性状。
方法
开展田间试验以确定每个物种对掩埋的响应。将树苗分别进行其高度的0%、10%、25%、50%和75%的掩埋处理。基于总生物量、高度、不定根产生量以及地上部分、根系和不定根生物量分配百分比与掩埋百分比的回归分析来评估掩埋响应。
主要结果
美国白松和白云杉缺乏掩埋耐受性。针对掩埋梯度，这些物种的总生物量呈现强烈的线性下降，不定根产生量极少，在中等掩埋水平（25% - 50%掩埋）时达到峰值，且地上部分与根系的生物量分配没有变化。具有耐受性的物种维吉尼亚刺柏、北美香柏和黑云杉对掩埋呈现二次响应，在掩埋高达50%时生物量变化不大，但在75%时大幅下降。这些物种在掩埋高达50%时产生大量不定根，但在整个掩埋水平范围内未改变分配模式。香脂杨和线叶柳受到掩埋的刺激。这些物种的生物量随着掩埋增加呈线性增加，在整个梯度上产生大量不定根，并且在高掩埋条件下明显将资源分配从原来的根系转向垂直地上部分生长和不定根产生。
结论
不定根产生以及对生物量的可塑性资源分配是加拿大中部海岸沙丘木本植物的适应性状，为评估全球海岸沙丘木本植物的掩埋耐受性提供了依据。
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