High-elevation angiosperms maintain extensive living storage tissue with large non-structural carbohydrate pools

Plant survival at extreme elevations depends on how carbon and nutrients are stored and mobilized at the cellular scale. High-elevation plants experiencing persistent cold and short growing seasons are predicted to maintain large pools of non-structural carbohydrates (NSCs) and extensive storage tissue that buffer metabolism and enhance stress tolerance, yet comparative evidence across diverse floras remains scarce. Here, we examine whether high-mountain plants in the western Himalayas increase NSC pools and, consequently, the proportion of storage tissue.

We analyzed 323 herbaceous species from the western Himalayas spanning 2,650 to 6,150 meters. For each species, storage organs were examined anatomically and chemically. Belowground tissues were sectioned to quantify parenchyma and lignified fractions, and the same organs were analyzed for soluble sugars, fructans, starch, nitrogen, and phosphorus. Relationships between elevation, tissue anatomy, plant height, and biochemical composition were evaluated using phylogenetically informed models.

Elevation increased NSC and nutrient concentrations, and these storage pools were linked to the expansion of parenchymatic tissue at the expense of lignified mechanical tissue. Plant height declined with elevation but showed no consistent relationship with anatomy, excluding a passive dwarfism explanation of increased parenchyma fraction. Among NSC classes, osmotically active soluble sugars and fructans, but not starch, were strong predictors of parenchyma abundance and also tracked elevation.

These coordinated anatomical and physiological shifts indicate a physiology-to-anatomy linkage in which elevation-related accumulation of mobile reserves and nutrients expands living storage cells, enhances cryoprotection by lowering cellular osmotic potential, limits ice propagation, and buffers metabolism against intermittent carbon and nutrient acquisition. By connecting cellular storage pools to tissue architecture across more than three hundred Himalayan species, this study reveals a widespread yet underexplored mechanism of alpine adaptation and provides a framework for understanding how storage physiology shapes plant persistence in cold, resource-limited ecosystems.