All results were presented as means with standard errors. The differences in
plant performance among different treatments were evaluated by a parametric oneway analysis of variance (ANOVA). Data were tested for their normality and variance prior to ANOVA.
If the difference among different treatments was significant at the 5% probability level, least significant difference (LSD) was calculated as the post hoc test to determine where the difference lay. The statistical analyses were performed using the SPSS 13.0 statistical package. All figures were created using the PC-based Origin 6.1 program.