Rising atmospheric carbon dioxide (CO₂) concentration and increasing temperature are major drivers of climate change, posing serious challenges to vegetable crop productivity, nutritional quality, and sustainability. Climate projections indicate that atmospheric CO₂ concentrations may exceed 500 ppm by the mid-twenty-first century, accompanied by a global temperature increase of 2–4 °C, conditions that are particularly critical for warm-season cucurbit crops. Understanding crop responses to individual and combined climate stressors across key developmental stages is therefore essential for developing climate-resilient production strategies. In this context, the present study investigated the morphological, physiological, biochemical, reproductive, and yield responses of ridge gourd (Luffa acutangula L. var. Pusa Nutan) to elevated temperature (32.3–32.5 °C) and elevated CO₂ (535–536 ppm), applied individually and in combination, under controlled environment chambers. Four treatments were imposed: ambient conditions, elevated temperature, elevated CO₂, and combined elevated temperature and CO₂. Elevated temperature alone significantly reduced leaf area, root-to-shoot ratio, flower production, fruit number, and protein content, while intensifying oxidative stress. In contrast, elevated CO₂ enhanced root and leaf growth, photosynthetic efficiency, antioxidant activity, and fruit yield. However, under combined exposure, elevated CO₂ only partially alleviated elevated temperature-induced stress, with high temperature exerting a dominant negative influence on yield and nutritional attributes. To integrate multiple plant responses, a Ridge Gourd Response Index (RGRI) was developed using principal component analysis. Elevated CO₂ exhibited the highest RGRI value (1.36), indicating superior plant performance, whereas the combined elevated temperature and CO₂ treatment recorded the lowest value (0.36). Overall, the results highlight the stage-specific and interactive effects of temperature and CO₂ on ridge gourd performance and underscore the importance of identifying climate-resilient traits to sustain cucurbit productivity under future climate scenarios.
Smiti et al. (Wed,) studied this question.