Fig. 1

a Response of different rice cultivars to salinity and Si. Plants were grown in hydroponics for 30 d at low (0.07 mM) and high (1 mM) ambient Si, with (50 mM NaCl) or without (0 mM NaCl) salt stress. Data show means (N = 3–5) with standard deviations. b Increasing external Si concentration reduces the growth loss caused by salinity. When external Si was raised from 0.07 to 1 mM an overall reduction in growth loss was determined. However, the level of ‘rescue’ (salt-induced growth reduction at high Si relative to salt-induced growth reduction at low Si) varies greatly between rice varieties. c Si Rescue is greater in salt tolerant rice cultivars. Raising ambient levels of Si from 0.07 to 1 mM, lowers the salt-induced growth penalty but less so in salt-sensitive cultivars. Salt sensitivity-ranking was done at high external [Si]. Inset shows large variation in Si Rescue and lack of correlation with salt sensitivity when cultivars are ranked for sensitivity at low external Si condition