Willows (Salix spp.) grown as short rotation coppice (SRC) are viewed as a sustainable source of biomass with a positive greenhouse gas (GHG) balance due to their potential to fix and accumulate carbon (C) below ground. However, exploiting this potential has been limited by the paucity of data available on below ground biomass allocation and the extent to which it varies between genotypes. Furthermore, it is likely that allocation can be altered considerably by environment. To investigate the role of genotype and environment on allocation, four willow genotypes were grown at two replicated field sites in southeast England and west Wales, UK. Above and below ground biomass was intensively measured over two two-year rotations. Significant genotypic differences in biomass allocation were identified, with below ground allocation differing by up to 10% between genotypes. Importantly, the genotype with the highest below ground biomass also had the highest above ground yield. Furthermore, leaf area was found to be a good predictor of below ground biomass. Growth environment significantly impacted allocation; the willow genotypes grown in west Wales had up to 94% more biomass below ground by the end of the second rotation. A single investigation into fine roots showed the same pattern with double the volume of fine roots present. This greater below ground allocation may be attributed primarily to higher wind speeds, plus differences in humidity and soil characteristics. These results demonstrate that the capacity exists to breed plants with both high yields and high potential for C accumulation.

中文翻译：

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柳树（Salix spp.）的高产生物量基因型在地下生物量分配方面表现出差异。


作为短轮伐林 (SRC) 生长的柳树 (Salix spp.) 被视为一种可持续的生物质来源，由于其在地下固定和积累碳 (C) 的潜力，具有正温室气体 (GHG) 平衡。然而，由于地下生物量分配的数据缺乏以及基因型之间的差异程度，利用这一潜力受到了限制。此外，分配可能会因环境而发生很大变化。为了研究基因型和环境对分配的作用，在英国东南部和威尔士西部的两个重复田间种植了四种柳树基因型。在两年的两次轮换中对地上和地下生物量进行了集中测量。生物量分配存在显着的基因型差异，不同基因型之间的地下分配差异高达 10%。重要的是，具有最高地下生物量的基因型也具有最高的地上产量。此外，叶面积被发现是地下生物量的良好预测指标。增长环境显着影响配置；到第二次轮作结束时，威尔士西部种植的柳树基因型的地下生物量增加了 94%。对细根的一次调查显示出相同的模式，细根的体积增加了一倍。这种更大的地下分配可能主要归因于更高的风速，加上湿度和土壤特性的差异。这些结果表明，存在培育高产量和高碳积累潜力的植物的能力。