Recovery of metabolites via subnivean photosynthesis in Arctic tundra plants: Implications for climate change

Plants have evolved numerous strategies for surviving the harsh conditions of the Arctic. One strategy for Arctic evergreen and semi-evergreen species is to photosynthesize beneath the snow during spring. However, the prevalence of this photosynthesis and how recent photosynthates are used is still unknown. Here we ask, how is newly acquired carbon beneath the snow allocated? To answer this question, we delivered isotopically labeled ¹³CO₂ to tussock tundra plants before snowmelt. Soluble sugars and starches were preferentially enriched with ¹³C in all five species tested, with lipids having comparatively low ¹³C enrichment. These results provide evidence of the recovery of metabolites used over the long winter. Additionally, these new soluble sugars may function in photoprotection and cold tolerance as plants release from snow cover. Climate change, by reducing the duration of subnivean photosynthesis of these species, will limit metabolite production before snowmelt, which may lead to a reduction in the ability of these species to compete effectively during the growing season, potentially leading to changes in community structure.