How Populus euphratica utilizes dew in an extremely arid region

Aims Dew is an important water source of plants in semi-arid and arid regions. However, there is not much evidence that this process is ecologically relevant for plants, especially in extremely desert riparian forest areas. We want to answer three key questions: 1) what are the positive effects of dew on plant growth? 2) Can the leaves absorb and use dew directly? 3) If the leaves can absorb dew, how is the absorbed water allocated? Methods We designed a two-factor control and stable isotope experiment to reveal the physiological and ecological responses of Populus euphratica seedlings to three different amounts of dew under different soil water contents. Results The leaf biomass, height growth, and the surface area of roots differed significantly between different amounts of dew under different levels of drought stress. Under different levels of drought stress, the Delta deuterium (delta D) value of plant, and soil water of seedlings in the dew treatment was significantly higher than that in the untreated group. Populus euphratica seedlings can absorb dew by direct foliar uptake and can redistribute the dew among plant organs and even the soil. Conclusions Dew treatments significantly promoted the growth and development and the fluorescence parameters (CYRILLIC CAPITAL LETTER EFPSII, ETR) of leaves of seedlings, especially under the soil moisture sufficient condition and under moderate drought. Obviously, the absorption and distribution of dew on leaves of Populus euphratica improved the soil moisture condition in the growing season and are important survival strategies for Populus euphratica to adjust to short-term drought.