Expression stability of candidate reference genes ranked by geNorm in different sample sets.

“1”: PGR subset, plant growth regulator treatment subset;“2”: M, stability measure;“*”: represents the optimal reference genes determined by pairwise variation analyses which are presented in Fig. 2. The recommended threshold of 0.15 is adopted.“1”: 植物生长调节剂（Plant Growth Regulator, PGR）子集，即植物生长调节剂处理子集；“2”: M值，即稳定性度量指标；“*”: 代表通过成对变异分析（该分析结果详见图2）确定的最佳内参基因，本研究采用推荐阈值0.15。