active growth stage的用法和样例：
- Egr-1 expression had relatively high level in active growth cells.
- Highly significant correlations were found between SPAD value and chlorosis score, active Fe content and pod yield at early growth stage.
- At early growth stage, SPAD value and active Fe content in young leaves of iron-resistant cultivars were significantly higher than those of iron-susceptible ones.
- Veneer grafting during the time of most active growth gives the best results.