Figure 1.

ABA contents of nitrate-treated seeds. A, ABA contents of seeds treated with endogenous nitrate. ABA content was determined in freshly harvested dry seeds from wild-type Col-0 plants grown with 10 mm nitrate (C10 control), with 50 mm nitrate (C50), and in the nia1 nia2 mutant seeds obtained with 10 mm nitrate nutrition (nia10). B, ABA contents of seeds treated with exogenous nitrate. Freshly harvested seeds from Col-0 plants cultivated with 10 mm nitrate were imbibed for 20 h in water or 10 mm KNO₃, and ABA content was determined by HPLC followed by immunodetection. Error bars indicate se (n = 5–7). Letters indicate the different groups displaying significantly different ABA levels (P < 0.05) after ANOVA analysis followed by Fisher's lsd test. DW, Dry weight.