Exogenous hormone on episperm development and ginkgolic acid accumulation in Ginkgo biloba L

Abstract

Ginkgolic acid is an anacardic acid specifically distributes in the seeds, leaves and episperms of Ginkgo biloba L. Ginkgolic acid possesses multiple biological functions on disease resistance and pesticide. Ginkgolic acid is enriched in the episperm of G. biloba, which is usually disposed as garbage. Although enriched, the content of ginkgolic acid in episperm is still low, and the extraction process is tedious and costly, which limits its application. In this study, we systematically observed the development process of G. biloba episperm, and detected the variation of endogenous hormone and ginkgolic acid levels therein. The results indicated that auxin, cytokinin and gibberellin (GA1 and GA3) content dramatically varied during the whole development process, indicating their regulation roles in episperm development. Remarkably, the salicylic acid (SA) content showed a significantly positive correlation with ginkgolic acid content. Based on these findings, we implemented exogenous hormone treatment with an optimized combination (300 mg/L NAA + 100 mg/L 6-BA + 200 mg/L SA) on the developing fruits of G. biloba, which resulted in a 53.92% increase of episperm yield and a 21.63% increase of ginkgolic acid content. Our study not only clarified the key development events of G. biloba episperm, the ginkgolic acid content profile, and their relationship, but also provides a cheap and easy way to improve ginkgolic acid accumulation in G. biloba seeds.