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 (Agrosds 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 mu mol mol(-1) or elevated CO2 concentration at 800 mu mol 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.