Abstract:Endogenous hormones, including gibberellin (GA4), indole acetic acid (IAA), isopentenyl adenine (iPA) and abscisic acid (ABA), were analyzed during bolting in spring radish (Raphanus sativus L.). Tissue from young leaves near the apex was analyzed with the ELISA. The results showed that an obvious peak value of GA4 content occurred at the bud-emerging point, indicating that this hormone is an important contributor to the bolting process. The ABA had a similar trend to that of GA4, while the IAA content was relatively low compared with that of GA4 and ABA. The content of iPA increased gradually during the bud-emerging stage and reached a maximum value at the late bolting period. The results also demonstrated that the balance of these endogenous hormones play an important role in the bolting process. A high ratio of iPA/ABA and low ratio of GA4/iPA and GA4/IAA were beneficial to floral bud differentiation and bolting in radish.