Fig. 3From: Selection and validation of appropriate reference genes for RT–qPCR analysis of Nitraria sibirica under various abiotic stressesPairwise variation (V) of the 10 candidate reference genes calculated by geNorm to determine the optimal number of reference genes for accurate normalization. A cut-off of 0.15 (Vn/n + 1 value) is usually appliedBack to article page