The ecological roles of seed mucilage on germination of Lepidium perfoliatum, a desert herb with typical myxospermy in Xinjiang

Myxospermy is considered as an adaptation to unideal habitats, which is characterized as a gelatinous layer of mucilage around the seed upon contact with water. Studies on the ecological roles of seed mucilage should provide valuable information on seed germination strategy. In the present study, the germination properties of Lepidium perfoliatum L., an early spring ephemeral plant with typical myxospermy in desert of northwestern China, were investigated with the intact seeds and demucilaged seeds under different conditions. Results revealed that, firstly, the seed mucilage was essential for intact seeds to germinate quickly and efficiently under abundant or excess water condition, while had no effect on relief of seed germination at low water potential or other stressful conditions; secondly, the presence of mucilage layer stimulated intact seed germination under relatively higher temperature, appropriate light, permeable soil matrix, which helps seed germinate efficiently under favorable conditions; thirdly, the existence of mucilage may limit air diffusion into seed and subsequently reduce germination, which might be a strategy to ensure a proportion of seeds staying in soil seed bank to wait for next favourable conditions. Our results suggest that the seed mucilage of L. perfoliatum applies multiple ecological roles in protection of seed germination to avoid unfavourable conditions, which should be an adaptation strategy for population survival and succession in a harsh desert environment.

Automated summary

The study investigated the germination properties of L. perfoliatum seeds under different conditions, revealing that seed mucilage promotes germination under abundant water, appropriate temperature, light, and soil conditions, but has no effect under low water potential. The presence of mucilage helps seeds germinate efficiently under favorable conditions, while limiting air diffusion into the seed to ensure a portion of seeds remain in the soil seed bank for future favorable conditions. The seed mucilage of L. perfoliatum plays multiple ecological roles in protecting seed germination, serving as an adaptation strategy for population survival and succession in harsh desert environments.