Fig. 1.

Conjugation of GA and SA in tomato. Tomato leaves were treated with 2 mM gentisic acid or salicylic acid for 4 h and 24 h, and the contents of the free and total GA and SA are shown in (A) and (B), respectively. Results are the means of three independent assays ±SD (standard deviation). (C) HPLC detection of the GA conjugate. Gentisic acid and UDP-xylose were incubated with crude tomato leaf extracts as described in the Material and methods. After 10 min, phenolics were extracted and analysed by HPLC. The peak corresponding to the more polar GA 5-O-β-D-xyloside appears at 13.1 min, while free GA peaks later at 13.8 min.