Plant Color as a Biological System Output: A Systems Framework Integrating Pigment Physiology, Environmental Drivers, Transport Constraints, and Optical Sensing

Plant coloration is a quantifiable physiological output that emerges from the regulated interaction of pigment biosynthesis and degradation, intracellular compartmentalization, vascular transport constraints, tissue microstructure, and environmentally mediated control mechanisms. Although informal and anecdotal approaches have proposed direct chemical injection or dye infusion as means to alter plant color, such interventions are fundamentally incompatible with living plant systems. Pigments are synthesized enzymatically and localized within specific intracellular compartments, and exogenous chemical introduction commonly disrupts osmotic balance, membrane integrity, and cellular viability, resulting in localized necrosis rather than controlled or stable pigment accumulation. In this work, we introduce the Pigment–Transport–Environment–Optics–Response (PTEOR) framework, a quantitative, time-resolved systems model that explicitly links internal pigment pools (chlorophylls, carotenoids, and anthocyanins), transport and compartmental constraints, tissue optical properties, and external environmental drivers to observed color expressed in spectral or color-space coordinates. By integrating established principles from plant biochemistry, transport physiology, and optical physics, the framework reformulates plant color from a descriptive or empirical trait into a predictable, measurable, and physiologically constrained system output. We further operationalize the PTEOR framework through a biologically safe experimental protocol designed for hot tropical climates, where elevated daytime temperatures and warm nights are known to suppress anthocyanin biosynthesis and accelerate pigment degradation. Using roses (Rosa spp.) as a model ornamental system, we demonstrate that controlled modulation of environmental variables—specifically light spectral composition and timing, thermal exposure, nitrogen availability, and water stability—during a defined pre-anthesis pigment-loading window produces reproducible and cultivar-specific color outcomes. These include enhanced red and pink saturation consistent with increased anthocyanin accumulation, improved chromatic clarity in yellow cultivars through preservation of carotenoid-dominated optical signatures, and reduced bronzing and spotting in white cultivars through minimization of stress-induced tissue injury. Color responses are quantified using calibrated imaging and reflectance spectroscopy, with periodic biochemical assays providing independent validation of pigment dynamics. Collectively, this work establishes a unified, mechanistic, and experimentally testable framework for understanding and managing plant coloration through endogenous physiological regulation rather than invasive manipulation. The PTEOR framework provides a robust scientific foundation for controlled ornamental coloration, non-destructive stress diagnostics in crops, and environment-driven plant monitoring using optical sensing, with clear applicability across horticulture, plant ecophysiology, and bio-inspired sensing systems Please check the attachment for details