Differential temperature adaptation mechanisms in the High Arctic-adapted Cerastium regelii Ostenf. and the widespread Stellaria longipes Goldie.

O_LIClimate change impacts arctic latitudes more acutely than other latitudes, resulting in arctic shrubification. How individual species in these climes respond to warming temperature is poorly understood. Understanding species resiliency to climate change will help us conserve plant species at risk. C_LIO_LIWe performed a survey of plants in a permafrost anomaly in Resolute (Qausuittuq), Nunavut, Canada. Two identified species, Stellaria longipes Goldie and Cerastium regelii Ostenf., were investigated through modelled niche suitability under future climate scenarios, phenological analysis, and in vitro warming experiments to investigate growth and phytochemical profiles. C_LIO_LI10 species including Stellaria longipes and Cerastium regelii were identified in the anomaly. Predicted niche suitability increased under SSP126 for C. regelii, with compressed and later flowering period since 1850. In vitro, S. longipes maximized growth at 24 {degrees}C with greater abundance of cytokinins than C. regelii, which increased growth at 28 {degrees}C. C_LIO_LIStellaria longipes is self-limiting at higher temperatures, and is less temperature-dependent for its success, while C. regelii is more affected by warming temperatures, showing increases in growth and predicted niche suitability. Our work increases understanding of plant resiliency and vulnerability in Canadas High Arctic, and sheds light on the biology of an understudied arctic specialist in C. regelii. C_LI