Pearson, K. J. | bioRxiv Science

bioRxiv2026

Warming Reduces Cold Hardiness of Boreal Plants but Damage Risk Varies by Species and Season

Winter warming is altering plant exposure to cold events, and its effects on seasonal cold hardiness dynamics remain poorly understood. Here we quantified the effect of whole-ecosystem warming (+0.00{degrees}C to +9.00{degrees}C) on bud cold hardiness of two overstory (Larix laricina and Picea mariana) and two understory (Chamaedaphne calyculata and Rhododendron groenlandicum) boreal peatland forest species across four dormant seasons. Warming reduced cold hardiness in fall and spring by delaying acclimation and advancing deacclimation, yet damage risk increased only in late winter and spring for three species. Warming also reduced snow cover, increasing temperature variability and cold damage for understory shrubs. Together, these results show that warming restructures rather than uniformly increasing cold hardiness risk, concentrating vulnerability at transitional seasons through species-specific dynamics and microclimate exposure.

plant biology↗

bioRxiv2026

Tracing PFAS Transfer from Mother to the Fetoplacental Unit: Insights from Trimester-Specific Maternal Serum Profiles

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous endocrine-disrupting pollutants that cross the placenta and affect offspring health, but the extent and timing of their transfer to placental and fetal compartments remain poorly understood. We characterized the relationship between trimester-specific prenatal maternal serum PFAS levels and paired placental and cord plasma levels at term. Data came from the Central Arkansas Glowing prospective cohort (n=151, 2010-2014). Four well-detected PFAS were measured using liquid chromatography-tandem mass spectrometry. Regression, elastic net, and parametric g-formula models tested the association between maternal levels in each trimester and placental or cord PFAS levels. In g-formula models, trimester one (T1) or trimester two (T2) measures consistently had the largest effect sizes associated with placental levels (p<0.001-0.05). Similarly, T1 (PFHxS, PFNA, PFOS, PFOA), T2 (PFNA, PFOS, PFOA), and placental PFOA were associated with cord plasma levels (p<0.05-p<0.001). Results were robust to time-varying adjustment for estimated glomerular filtration rate, serum albumin, or maternal weight. Predictive models improved with additional timepoint measures. Our findings suggest PFOA may transfer more efficiently from the placenta to cord plasma and early-to-mid gestation maternal serum PFAS measures may serve as the most robust sentinels of fetoplacental exposure burden, suggesting early exposure prevention should be prioritized.

pharmacology and toxicology↗