Author(s)

Piumi Maheshika Godakanda, Sahari Inoue, Binyam Tedla, Qing-Lai Dang^*

Faculty of Natural Resources Management, Lakehead University, Thunder Bay, Ontario, Canada.

Climate change impacts soil nitrogen, influencing plant responses to elevated atmospheric [CO₂]. Understanding the interaction between nitrogen supply and elevated [CO₂] is crucial for predicting plant future performance. This study examined the interactive effects of elevated [CO₂] and nitrogen supply on the eco-physiological performance of yellow birch. Seedlings were exposed to two [CO₂] levels and five nitrogen supply levels for 4 months. Growth parameters such as seedling height and root collar diameter increased with higher nitrogen supply and elevated [CO₂], while specific leaf area decreased. [CO₂] elevation and increasing nitrogen supply also increased the total and stem, and leaf biomass. The elevated [CO₂] increased the stem mass ratio but decreased the root-to-shoot ratio and root mass ratio. However, decreases in nitrogen supply increased root mass ratio and root-to-shoot ratio. The elevated [CO₂] increased the maximum rate of Rubisco carboxylation (V_cmax) and photosynthetic electron transport (J_max), but the effect on J_max was statistically significant only at the two highest nitrogen supply levels. The results indicate that yellow birch may increase photosynthetic capacity, biomass, and growth in the future when [CO₂] is higher.

Climate Change, Yellow Birch (Betula alleghaniensis Britt.), Elevated [CO₂], Soil Nitrogen Availability, Growth, Biomass, Photosynthesis

Godakanda, P. , Inoue, S. , Tedla, B. and Dang, Q. (2025) Effects of Nitrogen Supply on the Physiological and Morphological Responses to Elevated [CO₂] in Yellow Birch (Betula alleghaniensis Britt.). American Journal of Plant Sciences, 16, 88-113. doi: 10.4236/ajps.2025.161010.