Comparative Analysis of Endogenous Hormones and Metabolite Profiles in Early-Spring Flowering Plants and Unflowered Plants Revealing the Strategy of Blossom

Early-spring plants are a special type of plant that complete their life cycle promptly in cold, early spring. Very little effort has been made into researching the flowering mechanism of this type. Vernalization, as an indispensable process for flowering induction at low temperature, is likely to be closely related to life cycle transition in early-spring plants. To explore the flowering strategy at low temperature, this study selected two local early-spring flowering plant species ( Hylomecon japonica (Thunb.) Prantl, Smilacina japonica A. Gray) and two early-spring unflowered plants species ( Cimicifuga foetida L., Veratrum nigrum L.) as subjects. Firstly, the ratio of abscisic acid (ABA), gibberellic acid (GA3), indole-3-acetic acid (IAA), and cytokinin (CTK) hormones was analyzed through high-performance liquid chromatography–mass spectrometry, results of which indicated that early-spring flowering plants have completed vernalization and thus entered the flowering stage. IAA content in early-spring flowering plants was significantly lower than that of unflowered plants, while GA3 and ABA contents were higher. Secondly, gas chromatography coupled with mass spectrometry (GC–MS) was adopted to profile metabolite richness across the two types of plants. Integrated key metabolic pathway analysis suggested that the contents of D-ribose, L-valine, L-isoleucine, alanine as well as various other compounds participating in the key pathways of early-spring flowering plants significantly reduced, demonstrating that early-spring flowering plants consume a significant amount of energy to regulate flowering, that is sourced from mass carbohydrate consumption. These results provide a greater understanding of early-spring flowering plants and their metabolic mechanism of vernalization, laying the foundation for further exploration on early-spring plants as well as the processing mechanism of the plant life cycle.