title: Is white clover able to switch to atmospheric sulphur sources when sulphate availability decreases?
abstract: 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.
authors: Université de Caen, UMR 950 Ecophysiologie Végétale Agronomie et nutritions NCS, INRA/Université de Caen, Esplanade de la Paix, F-14032 Caen, France.
authors: Sébastien
authors: S
authors: Varin
authors: Servane
authors: S
authors: Lemauviel-Lavenant
authors: Jean-Bernard
authors: JB
authors: Cliquet
mesh_terms: D001272:Atmosphere / Q000032:analysis; D018515:Plant Leaves / Q000737:chemistry / Q000502:physiology; D018517:Plant Roots / Q000737:chemistry / Q000502:physiology; D018520:Plant Shoots / Q000737:chemistry / Q000502:physiology; D053204:Root Nodules, Plant / Q000737:chemistry / Q000502:physiology; D012987:Soil / Q000737:chemistry; D013431:Sulfates / Q000032:analysis / Q000378:metabolism*; D013455:Sulfur / Q000032:analysis / Q000378:metabolism; D029921:Trifolium / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*
chemical_list: D012987:Soil; D013431:Sulfates; D013455:Sulfur
keywords: 34S; Foliar uptake; plasticity; sulphate uptake; sulphur deficiency; sulphur deposition.