Fig. 9.

Effects of MSX pre-treatment on the induction of AtIPT transcript accumulation by exogenous nitrogen compounds. Arabidopsis seedlings were grown under standard conditions for 2 weeks after germination and transferred to nitrogen-free medium for 5 d. The seedlings were pre-treated with 1 mM MSX for 2 h and then incubated for 2 h with nitrogen-free medium (–N), 50 mM glutamine (+Gln) or 10 mM KNO₃ (+KNO₃) solution containing 1 mM MSX. Total RNA prepared from roots was subjected to qPCR which was performed in triplicate. The amounts of transcripts were normalized to that of the Actin 2 transcript. The experiment was independently repeated twice. The values were normalized with respect to those obtained in the nitrogen-free medium, and mean values with the SD are shown. Asterisks indicate significant differences between the nitrogen-free treatment and the Gln or nitrate treatment, according to Student’s t-test (**P < 0.01; *P < 0.05).