Physcomitrium patens response to elevated CO₂ is flexible and determined by an interaction between sugar and nitrogen...

Area of Science:

• Plant Biology
• Environmental Science
• Ecology

Background:

• Mosses play a vital role in carbon storage ecosystems like permafrost and bogs.
• Mosses are exposed to high CO2 levels due to their proximity to soil surfaces.

Purpose of the Study:

• To investigate the impact of elevated carbon dioxide (eCO2) on the growth and physiology of the moss *Physcomitrium patens*.
• To understand how nitrogen availability influences the response of *P. patens* to eCO2.

Main Methods:

• Cultivating *Physcomitrium patens* under elevated CO2 conditions with varying nitrogen sources (nitrate and ammonium).
• Analyzing phenotypic growth characteristics, including transition to caulonema, rhizoid development, and biomass accumulation.
• Measuring underlying physiological and metabolic changes, focusing on sugar signaling metabolites like T6P.

Main Results:

• Elevated CO2 significantly increased biomass and altered growth patterns in *P. patens*, including earlier transition to caulonema and longer, pigmented rhizoids.
• The sugar signaling metabolite T6P was identified as a key mediator of eCO2-induced growth enhancement.
• Nitrogen form critically influenced phenotypic plasticity: nitrate led to diffused growth, while ammonium promoted dense growth with taller gametophores.

Conclusions:

• *Physcomitrium patens* exhibits significant phenotypic plasticity in response to elevated CO2 and nitrogen availability.
• Understanding moss responses to eCO2 is crucial for refining climate change models and predicting ecosystem dynamics.
• The study provides a basis for comparing eCO2 responses across different plant groups.