Silicon Affects Plant Stoichiometry and Accumulation of C, N, and P in Grasslands
Silicon Affects Plant Stoichiometry and Accumulation of C, N, and P in Grasslands
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硅影响植物化学计量和草地中碳、氮和磷的积累
DOI：
10.3389/fpls.2020.01304
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发表时间：
2020-08-27
影响因子：
5.6
通讯作者：
Liu, Hongyan
中科院分区：
文献类型：
--
作者：
Hao, Qian;Yang, Shilei;Liu, Hongyan
硅在改善土壤养分有效性和植物碳(C)积累方面起着重要作用，因此可能对陆地生态系统中C、N和P的生物地球化学循环产生深远的影响。然而，尽管草原生态系统是生物源硅(BSI)最重要的累积者之一，但对这一过程的研究却很少。本研究采集了中国北部4种常见牧草的地上部分和土壤剖面样品，在景观尺度上分析了土壤中硅含量与牧草中C、N、P的化学计量和积累的关系。我们的结果表明，植物中的硅浓度与相关的碳浓度显著负相关(p<；0.01)。硅和氮浓度之间没有显著的相关性。值得注意的是，随着Si浓度的增加，P浓度从不到0.10%增加到0.20%以上，C：P和N：P比值随之降低。此外，土壤非晶态硅对C、N、P的积累起着比其他环境因子(如MAT、MAP和海拔)更重要的作用。这些结果表明，硅可以促进牧草对养分(C、N、P)的利用，特别是可以缓解草原的磷缺乏。我们认为，硅正向改变了C、N、P的浓度和积累，可能导致了植被和土壤凋落物分解的生态化学计量比的变化。这一研究进一步表明，硅的生理功能是影响草原生态系统碳、磷生物地球化学循环的一个重要但被忽视的因素。
Silicon (Si) plays an important role in improving soil nutrient availability and plant carbon (C) accumulation and may therefore impact the biogeochemical cycles of C, nitrogen (N), and phosphorus (P) in terrestrial ecosystems profoundly. However, research on this process in grassland ecosystems is scarce, despite the fact that these ecosystems are one of the most significant accumulators of biogenic Si (BSi). In this study, we collected the aboveground parts of four widespread grasses and soil profile samples in northern China and assessed the correlations between Si concentrations and stoichiometry and accumulation of C, N, and P in grasses at the landscape scale. Our results showed that Si concentrations in plants were significantly negatively correlated (p< 0.01) with associated C concentrations. There was no significant correlation between Si and N concentrations. It is worth noting that since the Si concentration increased, the P concentration increased from less than 0.10% to more than 0.20% and therefore C:P and N:P ratios decreased concomitantly. Besides, the soil noncrystalline Si played more important role in C, N, and P accumulation than other environmental factors (e.g., MAT, MAP, and altitude). These findings indicate that Si may facilitate grasses in adjusting the utilization of nutrients (C, N, and P) and may particularly alleviate P deficiency in grasslands. We conclude that Si positively alters the concentrations and accumulation of C, N, and P likely resulting in the variation of ecological stoichiometry in both vegetation and litter decomposition in soils. This study further suggests that the physiological function of Si is an important but overlooked factor in influencing biogeochemical cycles of C and P in grassland ecosystems.