Interconversion of gibberellin A4 to gibberellins A 1 and A 34 by dwarf rice, cultivar Tan-ginbozu.

Interconversion of GA4 to GA1 and GA34 occurred within 24 h of application of 1,2-[(3)H]-GA4 to seedlings of dwarf rice, cv. Tan-ginbozu. Identification was made by direct comparison of the trimethylsilyl ether derivatives of the methyl esters of Silica-gel partition-column fractions on gas-liquid radiochromatography with derivatized GA1 and GA34 standards on three columns: 2% QF-1, 2% SE-30, and 1% XE-60. GA2, an artifact of the purification and chromatography system, may also be formed by the plant. The conversions from GA4 to GA1 and GA34 are single hydroxylations. At least two unidentified radioactive products were also formed by the plant. Interconversions were in the order of 0.3 to 0.8% of applied [(3)H]-GA4.