Physiological and growth responses of Chinese chives (Allium tuberosum) to elevated CO2 concentrations and infestation by fungus gnat (Bradysia impatiens).

Elevated CO2 (eCO2) levels can alter plant physiology by reducing stomatal density, weakening transpiration, enhancing photosynthesis, accelerating growth, increasing the carbon-to-nitrogen ratio, and lowering nitrogen content. This study investigated the combined effects of eCO2 stress and Bradysia impatiens infestation on Chinese chive (Allium tuberosum) under controlled CO2 growth chamber conditions. A factorial experimental design was implemented, incorporating two CO2 concentration levels and three fungus gnat infestation intensities. The results revealed significant increases in leaf width, leaf thickness, soluble sugar and chlorophyll b levels in Chinese chive plants under both eCO2 and ambient CO2 (aCO2) conditions, irrespective of B. impatiens infestation status. Conversely, soluble protein content, chlorophyll a, and total chlorophyll concentrations showed significant reductions under both CO2 regimes, regardless of B. impatiens infestation. These findings demonstrate that the growth and physiological responses of Chinese chive are substantially influenced by insect infestation under projected eCO2 scenarios. This research provides valuable insights for developing adaptive strategies against B. impatiens infestations in the context of atmospheric change, contributing to sustainable agricultural practices under future climate conditions.