Fig. 1.

Flowering time varies according to nitrate availability. Arabidopsis plants were sown on vermiculite and watered once a week with N-free nutrient solution containing either 0.3, 0.5, 1, 3, or 10 mM KNO₃. Number of days to bolting and flowering (A, B), number of rosette leaves at bolting (C), and average number of rosette leaves per day (D) were determined. At least 20 plants were used for each quantification. Data are means and SD of three independent biological replicates. Asterisks and different letters indicate significant differences as determined by Tukey’s Multiple Comparison test (P≤0.01).