Mineral weathering and silicon uptake by rice plants promote carbon storage in paddy fields
Mineral weathering and silicon uptake by rice plants promote carbon storage in paddy fields
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DOI：
10.1080/00380768.2021.1878471
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发表时间：
2021-03
影响因子：
2
通讯作者：
Kanako Kusa;M. Moriizumi;S. Hobara;Mikoto Kaneko;S. Matsumoto;J. Kasuga;N. Ae
中科院分区：
文献类型：
--
作者：
Kanako Kusa;M. Moriizumi;S. Hobara;Mikoto Kaneko;S. Matsumoto;J. Kasuga;N. Ae
摘要增加土壤碳储量是应对全球气候变暖的一项潜在措施，但土壤碳积累的机制还不清楚。阐明这一机制将有助于开发土壤碳储存的新方法，例如在农业系统中。我们在缺钾和草酸的条件下种植了11年的高生物量饲料稻品种。水稻品种是健康的，没有钾或草酸缺乏的迹象。水稻植株吸收的钾和草酸的量大于土壤、肥料和灌溉水中的有效形式，表明矿物风化促进了初级矿物中钾、草酸和铝的释放。此外，在11年的水稻种植中，与活性铝结合的碳增加了69.4 kg C ha−1年−1。虽然水稻根分泌的有机酸被认为是根际土壤中强烈的矿物风化效应的一个因素，但从水稻根中只检测到极少量的有机酸。因此，有机酸不是促进矿物风化的因素。另一方面，在矿物粉末与从水稻根制备的细胞壁之间的接触反应中观察到钾和草酸的浸出。这些结果表明，水稻根表面的原生矿物质可以与细胞壁上的螯合位点反应，溶解钾、铝和草酸。在缺钾和缺酸的条件下，水稻植株吸收钾和大量的草酸。然后，高活性铝留在根际，在那里它结合有机质，产生持久的土壤碳。植物对草酸的吸收旺盛，可通过矿物风化作用增加活性铝，从而促进土壤中碳的积累。
ABSTRACT Increasing carbon storage in soil is a potential measure against global warming, but the mechanisms of carbon accumulation in soil are not well understood. Clarifying the mechanism would help in the development of new methods for soil carbon storage, such as in agricultural systems. We grew high-biomass forage rice cultivars for 11 years under conditions of potassium and silicic acid deficiency. Rice cultivars were healthy, without signs of potassium or silicic acid deficiency. The quantities of potassium and silicic acid absorbed by the rice plants were greater than those of available forms in the soil, fertilizer, and irrigation water, indicating that mineral weathering promoted the release of potassium, silicic acid, and aluminum from primary minerals. Furthermore, the carbon bound to active aluminum increased by 69.4 kg C ha−1 year−1 during 11 years of paddy rice cultivation. Although organic acids secreted by rice roots have been expected to be a factor in the strong mineral weathering effect in the rhizosphere, an only extremely small amount of organic acids were detected from rice roots. Therefore, organic acids are not a factor in promoting mineral weathering. On the other hand, leaching of potassium and silicic acid is observed in the contact reaction between the mineral powder and the cell wall prepared from rice root. These findings show that the primary minerals could be reacted with chelating sites on the cell wall of the rice root surface to dissolve potassium, aluminum, and silicic acid. The rice plants absorb potassium and a large amount of silicic acid under potassium and silicic acid deficient conditions. Then, the highly active aluminum remained in the rhizosphere, where it bound to organic matter, producing persistent soil carbon. Plants that can absorb silicic acid vigorously have a role of increasing active aluminum through mineral weathering, resulting contribute to carbon accumulation in soil.