Response Patterns and Mechanisms of Seed Germination and Mortality of Common Plants in Subalpine Wet Meadows to In Situ Burial

The effects of different storage conditions on seed germination and mortality may exhibit species-specific patterns. Burial serves as a natural seed storage mechanism, and its impact on seed germination and mortality holds critical implications for understanding the formation mechanisms of soil seed banks and the restoration of vegetation. Seed size is closely related to storage conditions, as it affects the ease with which seeds penetrate the soil, thereby potentially influencing their germination and mortality responses to those storage conditions. This study used 12 common plant species from a subalpine wet meadow. Employing in situ unheated storage as the control and in situ burial at a 15 cm depth (for seven months) as the experimental treatment, we aimed to explore the effects of burial on seed germination and survival, as well as the underlying mechanisms, in relation to seed size. The results showed the following: (1) Compared with the control, the burial treatment significantly increased the germination rates of four species (burial-promoted germination type), while no significant effect was observed on the germination of the remaining eight species (burial-insensitive germination type): it significantly increased the mortality rate of two species (survival-inhibited type), significantly decreased the mortality rate of four species (survival-promoted type), and had no significant impact on the mortality rate of the remaining six species (survival-insensitive type). (2) Seed size exhibited significant negative correlations with both post-burial germination rates and mortality rates under control conditions, while showing a significant positive correlation with the magnitude of mortality change. The species-specific responses of seed germination and mortality to storage conditions, and their close association with seed size, represent products of long-term plant evolution. This study provides important insights for understanding the mechanisms of soil seed bank formation and offers valuable guidance for vegetation restoration practices.