Fig. 2.

2′-Deoxymugineic acid (DMA) exudation rates (a) and total carbon (C) exudation rates (b) (nmol C g⁻¹ root DW s⁻¹, derived from total dissolved organic C analyzed) of wheat (Triticum aestivum cv Tamaro) grown on seven different calcareous soils. White numbers represent DMA-derived C as a percentage of total C released. Exudation was sampled hydroponically at 44 d after germination (DAG). Values represent means ± SE (n = 3). Letters indicate significant differences of DMA and total C release, with P < 0.05. Letters a, b: ANOVA including all soils, letters x, y: ANOVA excluding the saline soil Nadec. Sant, Santomera; Xer T, Xeraco topsoil; Xer L, Xeraco subsoil; Bol, Bologna; Nad, Nadec; Lass, Lassee; SL 10%, Siebenlinden + 10% CaCO₃.