FIGURE 1.

Variation in the germination rates among 21 rice genotypes with or without N. One hundred seeds of each of the 21 genotypes were plated in triplicate (300 seeds per treatment) on moist cotton and soaked with Arnon Hoagland medium with or without nitrate, ammonium, or urea as the sole source of N. Percent germination in each plate was monitored every 3 h until all the seeds have germinated and mean % values were plotted. Each curve represents a separate genotype and each graph corresponds to a different N regime such as distilled water (A), media without N (B), media with ammonium chloride (C), or ammonium nitrate (D), or calcium and potassium nitrate (E), or urea (F). The arrows represent the time taken for 50% seeds to germinate (t_½) deduced using X₀ function of SigmaPlot ver. 9.