Influence of daylength on gibberellin metabolism and stem growth inSilene armeria

✍ Scribed by H. Ende; J. A. D. Zeevaart

• Publisher: Springer-Verlag
• Year: 1971
• Tongue: English
• Weight: 654 KB
• Volume: 98
• Category: Article
• ISSN: 0032-0935
• DOI: 10.1007/bf00385349

✦ Synopsis

When radioactive gibberellin A 5 (aH-GA~) was applied to the apices and surrounding young leaves of the long-day plant Silene armeria, it was partially converted to at least two other acidic substances. One of them was similar to GA 3 in chromatographic, but not in biological properties. The other metabolite was more polar than GA 3 and inactive in the dwarf d-5 corn assay.

The rate of 3H-GA5 conversion was influenced by the photoperiod under which Silene plants were grown. Exposure to 2 long days significantly increased all-GAs metabolism over that in control plants kept under short days. The increased conversion of 3H-GAs persisted for at least a few days after transferring Silene plants back from long to short days. Likewise, stem growth induced by long photoperiods continued for a considerable period of time under subsequent short days.

Application of the growth retardant AM0-1618 to Silene reduced the levels of two endogenous GA-like substances, one of them with GAs-like properties, more under long than under short days. These results indicate that long photoperiods, which induce flower formation and stem elongation in Silene, increase the turnover of endogenous gibberellins.