Explants were treated for 4 weeks in each experimental condition. The culture medium was replaced once a week and the weight of explants was recorded. The daily growth rate of G. changii was determined according to Yong et al. (2013b) using formula GR = [(Wt/W0)1/t –1] × 100% where W0 is the initial fresh weight, and Wt is the final fresh weight of the explants after t days of culture. One-way analysis of variance (ANOVA) was conducted for each treatment group in order to verify if the differences between the control and treated samples were statistically significant. The statistical analyses were performed using statistical package software SPSS version 16, (SPSS, Chicago, IL).