Université de Caen, UMR 950 Ecophysiologie Végétale Agronomie et nutritions NCS, INRA/Université de Caen, Esplanade de la Paix, F-14032 Caen, France.
J Exp Bot. 2013 May;64(8):2511-21. doi: 10.1093/jxb/ert109. Epub 2013 May 4.
Sulphur (S) is one of the very few nutrients that plants can absorb either through roots as sulphate or via leaves in a gas form such as SO2 or H2S. This study was realized in a non-S-enriched atmosphere and its purpose was to test whether clover plants can increase their ability to use atmospheric S when sulphate availability decreases. A novel methodology measuring the dilution of (34)S provided from a nutrient solution by atmospheric (32)S was developed to measure S acquisition by Trifolium repens L. Clones of white clover were grown for 140 d in a hydroponic system with three levels of sulphate concentrations. S concentration in plants decreased with S deficiency and plant age. In the experimental conditions used here, S derived from atmospheric deposition (Sdad) constituted from 36% to 100% of the total S. The allocation of S coming from atmospheric and pedospheric sources depends on organs and compounds. Nodules appeared as major sinks for sulphate. A greater proportion of atmospheric S was observed in buffer-soluble proteins than in the insoluble S fraction. Decreasing the S concentration in the nutrient solution resulted in an increase in the Sdad:leaf area ratio and in an increase in the leaf:stolon and root:shoot mass ratios, suggesting that a plasticity in the partitioning of resources to organs may allow a higher gain of S by both roots and leaves. This study shows that clover can increase its ability to use atmospheric S even at low concentration when pedospheric S availability decreases.
硫（S）是植物可以通过根部吸收的极少数营养物质之一，也可以通过叶片以二氧化硫（SO2）或硫化氢（H2S）等气体形式吸收。本研究在非富硫环境中进行，旨在测试三叶草在硫酸盐供应减少时，是否能提高其利用大气 S 的能力。本研究开发了一种新的方法，通过测量营养溶液中（34）S 被大气（32）S 稀释的程度，来测量三叶草属（Trifolium repens L.）对 S 的吸收。将白三叶草的克隆体在水培系统中培养 140 天，硫酸盐浓度分为三个水平。随着 S 缺乏和植物年龄的增长，植物中的 S 浓度下降。在本实验中，大气沉降（Sdad）提供的 S 占总 S 的 36%至 100%。来自大气和土壤源的 S 分配取决于器官和化合物。根瘤是硫酸盐的主要汇。与不溶 S 部分相比，缓冲可溶蛋白中观察到更多的大气 S。减少营养液中的 S 浓度会导致 Sdad:叶面积比增加，以及叶片:茎和根:茎比值增加，这表明资源向器官分配的可塑性可能允许根和叶都能获得更多的 S。本研究表明，当土壤 S 供应减少时，三叶草即使在低浓度下也能提高利用大气 S 的能力。
