Comparison of 2-Acetyl-1-Pyrroline (2AP) in Rice Leaf at Different Growth Stages Using Gas Chromatography

Aromatic rice lines were examined for 2-Acetyl-1-Pyrroline (2AP) content in leaf tissue at five different growth stages (tillering, panicle initiation, 50% heading, booting, and maturity).A small plot trial with plot size of 1.42 m × 4.88 m (7 row-plots) was arranged in completely randomize design with three replications.Dry-seeded, delayed flood cultural practice was used in this study.The experiment was conducted at three locations.The average 2AP concentrations in leaf tissue at tillering stages were higher than the other four growth stages.2AP levels were declined when rice plant reached booting.AP levels decreased slightly at heading stage and decreased significantly at maturity.There was no significant different between 2AP in leaf at 50% heading from three locations as well as the 2AP content in rice grain.Correlations between 2AP in leaf and 2AP in grain were significantly in all five growth stages.The highest correlation coefficient was found between 2AP in leaf at booting and grain (r = 0.811**) and lowest was in the leaf at harvest (r = 0.564**).Results indicated that 2AP could be determined in leaf tissue at early growth stage.