Analysis of SA content
Two-month-old WT and OE lines were used as experimental materials. The leaves of plants grown under well-watered conditions and dehydration for 4 h were collected and immediately frozen in liquid nitrogen. The leaves were ground into powder in liquid nitrogen, and 50 mg powder was used for quantitative free-SA measurements by high-performance liquid chromatography–tandem mass spectrometry (Pan et al. , 2010).