Mohan K. Bista, Purushothaman Ramamoorthy, Ranadheer Reddy Vennam, Sadikshya Poudel, K. Raja Reddy, Raju Bheemanahalli
录用日期: 2025-04-07
Elevated CO2 (eCO2) may mitigate stress-induced damage to cotton (Gossypium spp.) growth and development. However, understanding the early-stage responses of cotton to multiple abiotic stressors at eCO2 levels has been limited. This study quantified the impacts of chilling (CS, 22/14°C, day/night temperature), heat (HS, 38/30°C), drought (DS, 50% irrigation of the control), and salt (SS, 8 dS m-1) stresses on pigments, physiology, growth, and development of fourteen upland cotton cultivars under ambient CO2 (aCO2, 420 ppm; current) and eCO2 (700 ppm; future) levels during the vegetative stage. The eCO2 partially negated the effects of all stresses by improving one or more of the pigments, physiological, growth, and development traits, except CS. For instance, HS at aCO2 significantly increased stomatal conductance by 36% compared with non-stressed plants at aCO2. However, HS at eCO2 significantly decreased stomatal conductance by 18% compared with HS at aCO2. The first squaring was delayed by one day under SS at aCO2 but two days earlier under SS at eCO2 than non-stressed plants at aCO2. Root and shoot dry mass and the total leaf area were significantly higher under all stresses, except for CS, at the eCO2 compared with similar stresses at the aCO2. Most growth and development traits, including plant height, leaf area, and shoot dry mass, displayed a mirroring response pattern between aCO2 and eCO2 under all environments except CS. Cultivars exhibited significant interaction with stressed environments. Further, results revealed differential sensitivity and adaptation potential of cultivars to stress environments at varying CO2 levels. This study highlights the need to consider eCO2 in designing breeding programs to develop stress-tolerant varieties for future cotton-growing environments.