Figure 2.
A PLC inhibitor blocks the increase in [Ca2+]cyt and IP3 levels in response to nitrate treatments in Arabidopsis roots. Wild-type plants expressing WT-AQ were grown hydroponically for 2 weeks with 1 mm ammonium as the only nitrogen source, and [Ca2+]cyt and IP3 levels were assayed as described in the text. [Ca2+]cyt levels were monitored in excised roots pretreated with U73343 (nonfunctional analog; A) or U73122 (PLC inhibitor; B) after we treated with KNO3 and KCl. C, Plants were pretreated with mock, U73122 (inhibitor of PLC), or U73343 (analogous no function), and we evaluated the IP3 content in Arabidopsis roots in response to 5 mm KNO3 or KCl. Values plotted correspond to the means of three independent biological replicates ± sd. Gray bars represent time zero (before treatment), white bars represent KCl treatment, and black bars represent KNO3 treatment. The letters indicate means that significantly differ between control and treatment conditions (P < 0.05).