Plants in a crowded stand regulate their height growth so as to maintain similar heights to neighbours even when they have potential advantages in height growth
Plants in a crowded stand regulate their height growth so as to maintain similar heights to neighbours even when they have potential advantages in height growth
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DOI：
10.1093/aob/mcr109
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发表时间：
2011-07-01
期刊：
影响因子：
4.2
通讯作者：
Hikosaka, Kouki
中科院分区：
文献类型：
--
作者：
Nagashima, Hisae;Hikosaka, Kouki
背景和目的虽然高是有利的光竞争，植物高度生长往往是相似的优势植物在拥挤的立场（高度收敛）。以前的理论研究表明，植物不应该超过邻居，因为在较高的植物中，需要更多的支持组织，这反过来会降低叶质量分数，从而降低碳增益。然而，这个模型假设，竞争对手具有相同的潜力，他们的邻居的高度增长，这并不一定占的事实，即高度收敛甚至发生在个人之间的各种bioma.Methods独立盆栽植物的藜album的立场，其中目标植物被解除overtop邻居或降低被overtoped。被举起的植物预计将保持越顶，因为它们拦截更多的光，而不增加分配给茎，或调节其高度，以类似的水平的邻居，节省生物量分配给支持器官。降低植物预计将受到抑制，由于低光可用性或增加高度生长，以便有类似的高度到neighbors.Key Results解除植物降低高度的增长，尽管事实上，他们收到了更高的辐照度比别人。降低植物，另一方面，增加了茎伸长的速度，尽管减少辐照。因此，被举起和放下的植物都聚集在同一高度。与预期相反，解除植物并没有增加分配叶质量，尽管茎长减少。相反，它们将更多的生物量分配给根部，这可能有助于改善机械稳定性或水分状况。研究表明，叶片质量分数的降低并不是越顶邻居的唯一成本。风吹，这可能会增加蒸腾和拖曳力，可能会限制越顶植物的生长。结论表明，植物在拥挤的立场，调节自己的高度生长，以保持类似的高度，以邻居，即使他们有潜在的优势，在高度增长。这可能有助于避免由风吹引起的应力。
Background and Aims Although being tall is advantageous in light competition, plant height growth is often similar among dominant plants in crowded stands (height convergence). Previous theoretical studies have suggested that plants should not overtop neighbours because greater allocation to supporting tissues is necessary in taller plants, which in turn lowers leaf mass fraction and thus carbon gain. However, this model assumes that a competitor has the same potential of height growth as their neighbours, which does not necessarily account for the fact that height convergence occurs even among individuals with various biomass.Methods Stands of individually potted plants of Chenopodium album were established, where target plants were lifted to overtop neighbours or lowered to be overtopped. Lifted plants were expected to keep overtopping because they intercept more light without increased allocation to stems, or to regulate their height to similar levels of neighbours, saving biomass allocation to the supporting organ. Lowered plants were expected to be suppressed due to the low light availability or to increase height growth so as to have similar height to the neighbours.Key Results Lifted plants reduced height growth in spite of the fact that they received higher irradiance than others. Lowered plants, on the other hand, increased the rate of stem elongation despite the reduced irradiance. Consequently, lifted and lowered plants converged to the same height. In contrast to the expectation, lifted plants did not increase allocation to leaf mass despite the decreased stem length. Rather, they allocated more biomass to roots, which might contribute to improvement of mechanical stability or water status. It is suggested that decreased leaf mass fraction is not the sole cost of overtopping neighbours. Wind blowing, which may enhance transpiration and drag force, might constrain growth of overtopping plants.Conclusions The results show that plants in crowded stands regulate their height growth to maintain similar height to neighbours even when they have potential advantages in height growth. This might contribute to avoidance of stresses caused by wind blowing.