Thermal Adaptation Strategies in Waterleaf (Talinum triangulare Jacq.): Balancing Biomass Production and Nutritional Quality Under Climate Change

This study investigated the morphophysiological and biochemical responses of waterleaf (Talinum triangulare Jacq.) to different temperature regimes (18°C, 22°C, 25°C, and 35°C) to assess its potential as a climate-resilient crop. Through controlled-environment experiments, we demonstrated that temperature significantly (p < 0.05) influenced all measured morphophysiological and biochemical parameters. Plants grown at 35°C showed maximal biomass production (57.80 g fresh weight; 2.4-fold higher than at 25°C) but exhibited oxidative stress (8.7 nmol/g MDA) and altered metabolite profiles. The 25°C regime optimized the balance between yield and nutritional quality, maintaining high photosynthetic efficiency (Fv/Fm = 0.80) while accumulating beneficial phytochemicals (15.2 mg GAE/g phenolics). Cooler temperatures (18°C) severely limited growth (4.55 g fresh weight) despite some metabolic advantages of high accumulation of antioxidant compounds. Principal component analysis distinguished treatment responses along two primary axes: PC1 (68.83% variance) separated 35°C-grown plants, characterized by vigorous growth (2.4-fold greater biomass than 25°C), from 18°C plants showing metabolic suppression (p < 0.05). PC2 (22.97% variance) revealed a secondary gradient of photosynthetic efficiency (Fv/Fm = 0.81 at 35°C vs. 0.74 at 18°C) and oxidative stress (MDA levels 2.7 vs. 2.4 nmol/g FW), with 25°C plants exhibiting optimal balance between these parameters. These findings establish that waterleaf employs distinct adaptation strategies across temperature regimes, with 25°C representing the optimal compromise between productivity and nutritional value. The study provides critical data for cultivating waterleaf as a sustainable crop under climate change, recommending temperature-specific management strategies tailored to either biomass production (35°C) or nutrient-dense leaf production (25°C).