Ultrasound promotes germination of aging Pinus tabuliformis seeds is associated with altered lipid metabolism

Seed germination is an essential biological process for establishing new organisms of higher plants, it is especially significant for those aged seeds stored in gene banks for years. In this study, we investigated ultrasound treatment induced germination for aged Pinus tabuliformis seeds, which has been used in large scale aircraft sowing based afforestation in North China over 30 years' ago without knowing possible mechanisms. We showed certain strength of ultrasound could increase the germination rate of aged seeds for about 3 times compare with control. Interestingly, although our transcriptome and lipidome analysis showed the differences between control and ultrasound treatments can be observed 1 day after germination by partial least squares discriminant analysis (PLSDA) analysis, majority (75 % or 69 %) of the significantly altered genes or lipids were commonly shared between them. Further analysis for the commonly altered lipids between both treatments showed ultrasound provoked the variations of lipids during germination process. Our investigation also revealed large amount of ultrasound-related genes and lipids that might be involved in germination promotion process. We hypothesis ultrasound provokes seed lipidome which further increases seed germination of Pinus tabuliformis. Our study provides new insides into the role of ultrasound induced lipidome change in seed germination. Moreover, we provide a new method to improve germination of aged seeds which might benefit preservation of seeds in gene banks.