Enhanced stolon growth and metabolic adjustment in creeping bentgrass with elevated CO₂ concentration

Stolon growth and proliferation are highly desirable traits for stoloniferous plant species. The objectives of this study were to elucidate the effects of elevated CO₂ on stolon growth in a stoloniferous perennial grass species, creeping bentgrass (Agrostis stolonifera), and identify metabolites and associated metabolic pathways for CO₂-regulation of stolon growth under well-watered and drought conditions. Plants were grown under either ambient CO₂ concentration at 400 μmol mol⁻¹ or elevated CO₂ concentration at 800 μmol mol⁻¹ and subjected to well-watered control or drought stress by withholding irrigation in growth chambers. Elevated CO₂ led to increased number of stolon internodes and stolon length, and mitigated drought damages to creeping bentgrass, as manifested by the increased leaf relative water content and reduced electrolyte leakage. Elevated CO₂ increased stolon content of metabolites involved in carbohydrate reserves, respiratory metabolism, and membrane maintenance, including maltose, mannobiose, galactinol, 5-oxoproline, galacturonic acid, glycolic acid, gluconic acid, isoferulic acid, citric acid, threonic acid, lactic acid, succinic acid, and linolenic acid and linoleic acid. The CO₂-reponsive metabolites for carbohydrate reserves, respiratory metabolism, and membrane maintenance could contribute to the enhanced stolon growth, thereby potentially facilitating rapid stand establishment and increasing shoot biomass production in perennial grass species.