Investigation of temporal variations in endogenous gibberellin A3 and A4 in the leaves of birch (Betula platyphylla)

Abstract

Bioactive gibberellins (GAs) affect nearly every process during plant growth and development. In the present study, endogenous GA3 and GA4 levels in young leaves of 2- to 4-year-old birch (Betula platyphylla) trees were analyzed using liquid chromatography–tandem mass spectrometry (LC–MS/MS) during the phase from May to August. Concurrently, changes in the levels of GAs during each day were also determined in 4-year-old trees. Furthermore, the levels of GAs were analyzed in 15 four-year-old juvenile birch trees (yet to bolt/flower) and in 15 adult trees (just starting to bolt/flower) during different stages of growth. Our results displayed the basic various patterns of GA3 and GA4 levels of the transient variation over a single day and the periodic variation in the growth period from May to August in different ages of birch trees. The results suggested that GA3 and GA4 had a significant effect on promoting birch growth and flowering. This study also defined the optimal time period for the determination of a foliar spray of GA3 and GA4 to promote birch growth. Our study provides a theoretical foundation for the further investigation of the effects of GA3 and GA4 on the growth and development of birch trees.