A Unified Survival-Based Energy Framework for Plant Sweetness, Taste, and Fragrance

Sweetness, taste, and fragrance are emergent quality traits that arise from complex interactions between carbon assimilation, secondary metabolism, transport processes, and environmental conditions. Although the biochemical pathways governing soluble sugar accumulation, organic acid balance, amino acid metabolism, and volatile organic compound (VOC) synthesis are well established, current interpretations largely treat these traits as localized metabolic outputs. Such approaches implicitly assume that absorbed carbon and energy are readily available for sensory compound synthesis, and therefore provide limited explanatory power for widely observed field phenomena, including reduced sweetness under drought, diminished aroma under high evaporative demand, saturation of flavor under high irradiance, and rapid recovery of sensory quality following irrigation or nutrient supplementation. Here we present a unified, thermodynamically consistent energy framework that interprets plant sweetness, taste, and fragrance as survival-limited expressions of absorbed energy and material resources, rather than as synthesis-limited biochemical traits. Central to this framework is a dimensionless energy survival factor, Ψ=AE/TE+ε where AE represents absorbed and retained energetic and elemental resources available for secondary metabolism, TE denotes transport-, transpiration-, diffusion-, and respiration-driven losses, and ε captures irreducible entropy-producing degradation inherent to non-equilibrium biological systems. By construction, 0