Expression stability of the reference genes according to Brunner et al (2004) . Regression of Cq values against sample was calculated. (A) Samples were ordered according to clone and treatment, (B) samples were ordered according to ascending Cq values. For genes with high expression stability, the slope of the regression line is low and the fit is close. WW, well-watered; WL 50%, water limited (50% less water than control); WL 75%, water limited (75% less water than control). ACT, actin; EF1, elongation factor 1; UBQ, ubiquitin; n = 3.