Starch and sucrose metabolism are activated by cold treatment and exogenous GA₃ treatment in the germination process of Cerasus humilis seeds

Abstract

Cerasus humilis, which is known for its significant resistance to cold, drought, and salinity, is a perennial shrub in China. Despite its significant economic and ecological benefits, large-scale cultivation of this species is limited by the deep dormancy of its seeds. The seeds were subjected to treatments at 4 °C (LT) and 400 mg·L^-1 GA₃ combined with 4 °C (GALT) to promote germination. The germination initiation period for the LT and GALT treatments was observed at 60 and 15 days of stratification, respectively, while germination was completed at 105 and 60 days. These results indicate that the GALT treatment shortens the germination period by approximately 30 days compared to the LT treatment, making it the more effective treatment. Transcriptomic analyses were performed to investigate the molecular mechanisms underlying the germination process and the promoting effect of exogenous GA₃ on seed germination. The results indicated that, in both treatment groups, the metabolic pathways associated with starch and sucrose were activated, thereby enhancing the degradation of starch and sucrose to supply the necessary energy required for germination. Meanwhile, exogenous application of GA₃ can enhance α-amylase activity by promoting Ca²⁺ influx through Ca²⁺ channels, thereby accelerating starch degradation and providing energy for seed germination. Furthermore, the levels of metabolites and genes involved in plant hormone signaling, phenylpropanoid metabolism, and MAPK signaling pathways were markedly elevated. This study establishes a theoretical foundation for elucidating the germination mechanism of seeds that are difficult to germinate.

Keywords: Ca(2+) channel; Cerasus humilis; Hormones; Seed germination; Starch; Sucrose.