The effect of different pericarp color on seed germination of Centella asiatica (L.) urban

As an important medicinal plant, Centella asiatica (L.) Urban has been used in large amount for medicinal purposes. Propagation, such as by seed, could be useful to fulfill C. asiatica requirement. It has been reported that C. asiatica seeds can only germinated within 1-2 months after sown, when the pericarp color looks brown. But, there was no report regarding the effect of different pericarp color upon C. asiatica seed germination ability, in which the pericarp color is suggested to be correlated with seed development stages. The germination percentage of 4 seed categories of C. asiatica seed, i.e. green (G), yellowish green (YG), greenish yellow (Y), and brown (B), have been observed. Each categories were sown in 0.7% agar medium without GA₃, and with 5 and 10 GA₃. The result showed that the G, YG, Y, and B seeds generated germination percentage of 0%, 7.5%, 52.5%, and 15%, respectively, in medium without GA₃. Y seeds, which showed the highest germination percentage, are assumed to be in physiologically maturity stage, while B seeds are assumed in dormant stage, and G and YG are assumed in immature stage. All seed categories did not show germination response on medium with GA₃ application, except Y seeds, which the germination percentage decreased on medium with 5 GA₃ application. It is known that the pericarp color of C. asiatica seeds affected the seed germination percentage, especially on Y seed category, meanwhile GA₃ application only affected Y seeds category by decreasing the germination percentage.