Quantification of GA1, GA3, GA4, GA7, GA9, and GA20 in vegetative and male cone buds from juvenile and mature trees of Pinus radiata

The gibberellins GA1, GA3, GA4, GA7, GA9 and GA20 were quantified in vegetative and pollen cone buds of juvenile and mature trees of Pinus radiata by combined gas chromatography-mass spectrometry and selected ion monitoring (GC-MS-SIM) using deuterated GAs as internal standards. Higher levels of GA7 and GA9 and lower levels of GA4 were detected in juvenile vegetative buds compared to mature buds, and there were no differences in relation to age for GA1, GA3 and GA20. Conversely, when differences between vegetative and pollen cone buds from a mature tree were studied, the highest levels of GA1 and GA4 were found in pollen cone buds, similar levels of GA3, GA7 and GA9 were observed in both, and ten fold lower levels of GA20 were found in pollen cone buds as compared with vegetative buds. These results indicate a difference in GA metabolism in relation to both the tree age as well as the physiological status of buds: vegetative or reproductive in this conifer.