Water Availability and Leaf Microstructures Jointly Regulate Dew Absorption in Plants with Different Ecotypes

Dew formation occurs frequently and in substantial amounts, serving as an important water source with significant ecological implications for plant growth. Although previous studies have demonstrated that dew can supplement leaf water, quantitative evidence of leaf dew absorption under different dew intensities remains limited. In this study, a stable isotope tracer experiment was conducted to quantify dew absorption under varying dew amounts and to analyze absorption rates and influencing factors across different plant species. Results showed that all four species were capable of absorbing dew, mainly due to specialized leaf surface morphology and microstructures. At a dew intensity of 0.1 mm, <i>Tillandsia ionantha</i>, whose leaves are densely covered with shield-like trichomes, exhibited an extremely high dew absorption rate of 92%. In contrast, the leaf surface of purple shamrock (<i>Oxalis triangularis</i> 'Purpurea') is covered with abundant hydrophobic trichomes that strongly restrict dew entry, resulting in a very low absorption rate of only 1.43%. Dew absorption varied markedly among species under different dew amounts. Under dew intensities of 0.1, 0.2, and 0.3 mm, <i>T. ionantha</i> showed consistently high absorption rates of 92%, 89.60%, and 71.74%, respectively, whereas <i>Epipremnum aureum</i> exhibited much lower rates of 3.72%, 6.15%, and 2.45%. Moreover, under a dew intensity of 0.2 mm, dew absorbed by <i>E. aureum</i> leaves could be transported to the roots, indicating internal redistribution of foliar-absorbed water. Overall, dew represents an important supplementary water source for plants, and interspecific differences in leaf surface morphology and microstructures lead to substantial variation in dew absorption capacity. These findings provide experimental evidence for understanding species-specific strategies of dew utilization and have implications for the efficient use of dew as a water resource.