Physcomitrium patens responses to elevated CO2 and nitrogen

With atmospheric CO₂ levels increasing 100 times faster than historical levels, much attention has been paid to how crop plants respond to this elevated CO₂ (eCO₂). For angiosperms, eCO₂ leads to increased CO₂ assimilation and decreased photorespiration, but over time plants can adapt, leading to lower stomatal conductivity, and ultimately lower rates of nitrogen assimilation. Although not significant food sources for humans, mosses are important carbon sinks and critical components of many ecosystems, yet their responses to eCO₂ have not been examined in detail. Here, Mohanasundaram et al. explored how the model moss Physcomitrium patens responds to eCO₂. The authors measured growth rates and growth patterns and quantified key metabolites. They noted faster growth and life cycle progression under eCO₂, with similar effects upon glucose treatment; these are likely responses to enhanced sugar signaling. The growth patterns were also impacted by the availability of nitrogen in the growth medium; for example, elevated nitrogen preferentially promoted growth in photosynthetic tissues. These findings demonstrate coherent moss responses to changes in exogenous CO₂ and nitrogen levels, which can be useful for future ecosystem and climate models. (Summary by Mary Williams @PlantTeaching) New Phytol. 10.1111/nph.19348