Aerial Roots as Indicators of Whole-Plant Wellbeing a 40-Year Comparative Longitudinal Study

Aerial roots have long been treated as distress signals — signs that a plant is struggling, starved of nutrients, or failing underground. Drawing on a 40-year observational record encompassing 180 species across herbs, shrubs, and trees, this study challenges that view directly. We show that aerial root formation correlates strongly with plant vigour, developmental maturity, and resource surplus — not deficiency. Across the dataset, species that naturally form aerial roots do so almost exclusively when their physiological and structural state exceeds what is strictly needed for survival. We introduce the Wellbeing Threshold Model (WTM) — a formal framework proposing that aerial root formation is associated with a species-specific wellbeing threshold (Wcrit). When the composite Wellbeing Index (Wp), integrating carbon surplus (Cs), hormonal balance (H), and reproductive output (Ro), exceeds Wcrit, aerial root development becomes possible. The WTM is presented as a hypothesis-generating framework whose mechanistic basis requires direct experimental testing rather than a definitively validated causal model.

Aerial Roots, Plant Wellbeing, Wellbeing Threshold Model (WTM)

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