Objective: To lay the foundation for quality evaluation of medicinal materials of Amomum tsao-ko and its selection of fine varieties, the variation of percentage of volatile oil in the seeds among populations and individuals and its influencing factors were studied.
Methods: Extracted volatile oil from the seeds according to the Chinese Pharmacopoeia, studied quantitative characters of fruit, and analyzed the data according to SPSS 13.0.
Results: The percentage of volatile oil in seeds was greatly significantly different among the 7 populations (P = 0.000 < 0.001), and among different individuals (P = 0.000 < 0.001). A significantly positive correlation was detected between the percentage of volatile oil in seeds and length of fruit (P = 0.024 < 0.05), and significantly negative correlation occurred between the percentage and other quantitative characters or factors, viz. thousand seeds weight (P = 0.031 < 0.05), flower number per inflorescence (P = 0.028 < 0.05), weight of seeds masses per fruit (P = 0.038 < 0.05), altitude (P = 0.014 < 0.05), and latitude (P = 0.000 < 0.001). The regression equation (Y = 1.031 - 1.744 X2 - 1.119 X3 + 2.207 X1) was the optimal regression model of percentage of volatile oil in seeds (X1, X2 and X3 were respectively represented as the length and length-width ratio of fruit,and the weight of seeds masses).
Conclusion: Environmental factors influence greatly significantly on the percentage of volatile oil in seeds. The production and accumulation of volatile oil would decrease with altitude and latitude increasing. The longer fruit has the higher percentage volatile oil.