Comparison of the growth traits of a commercial pioneer tree species, paper mulberry (Broussonetia papyrifera L. Vent.), with those of shade-tolerant tree species: investigation of the ecophysiological mechanisms underlying shade-intolerance
Comparison of the growth traits of a commercial pioneer tree species, paper mulberry (Broussonetia papyrifera L. Vent.), with those of shade-tolerant tree species: investigation of the ecophysiological mechanisms underlying shade-intolerance
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DOI：
10.1007/s10457-014-9735-0
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发表时间：
2014-08
影响因子：
2.2
通讯作者：
Y. Miyazawa;Chanhsom Manythong;S. Fukuda;K. Ogata
中科院分区：
文献类型：
--
作者：
Y. Miyazawa;Chanhsom Manythong;S. Fukuda;K. Ogata
在老挝北方的农村地区，一种具有商业价值的先锋树种--桑葚（Broussonetia papyriferaL.）通风口。）已被推荐为间作下种植的商业树木。然而，对这种先锋树种在林下的生长和耐荫性的机制知之甚少。在4种光照强度下测定了桑葚幼苗的生长特性。我们比较了地上生物量和站立叶面积（RGRmassand RGRleaf），光捕获效率和种子水平的质量为基础的每日光合速率（Amass）的相对增长率与田间生长的幼苗的8个耐阴的物种，以确定可能导致耐阴的因素。桑葚的多数生长性状与耐荫树种无明显差异。生理生态-结构模型软件显示，耐荫树种的Amass和RGR容量高于耐荫树种。尽管它们的RGRmass较高，但由于叶片寿命短，在遮荫条件下，桑葚幼苗的RGRleaf为负。桑葚的RGRmass-RGRleaf线性关系具有较高的RGRmassintercept，表明提供阳性RGRleaf需要较高的RGRmass-RGRleaf。逐步减少立叶面积随着时间的推移，可能是光合作用，似乎是负责的耐荫性的桑树。虽然在该物种的原产地已经建议了间作，但层下栽培的构桑葚只有在相对开放的树冠下才有可能。
In rural areas of northern Laos, a commercially valuable pioneer tree species, paper mulberry (Broussonetia papyriferaL. Vent.) has been recommended for intercropping under plantations of commercial trees. However, less is understood about the growth of this pioneer tree species in the understorey and the mechanism underlying the shade intolerance. We measured growth characteristics for seedlings of paper mulberry under four light intensities. We compared the relative growth rates in aboveground biomass and standing leaf area (RGRmassand RGRleaf), light-capture efficiency, and seeding-level mass-based daily photosynthetic rates (Amass) with those of field-grown seedlings of eight shade-tolerant species to identify factors potentially responsible for shade-intolerance. Most growth traits of the paper mulberry seedlings did not differ consistently from those of the shade tolerant species. The ecophysiological–architectural model software showed higherAmassand RGRmasscapacity in paper mulberry than in shade-tolerant species. Despite their higher RGRmass, paper mulberry seedlings had negative RGRleafunder shaded conditions due to short leaf lifespan. The linear RGRmass–RGRleafrelationship for paper mulberry had a high RGRmassintercept, indicating that a high RGRmasswas required to provide positive RGRleaf. Progressive decreases in standing leaf area with time, and possibly photosynthesis, appear to be responsible for the shade-intolerance of paper mulberry. Although intercropping of paper mulberry has been suggested in the species’ native region, understorey cultivation of paper mulberry would only be possible with relatively open canopies.