Al204

We measured SLA(cm² g⁻¹) for each individual as the area of fresh leaves divided by their oven-dry mass. To determine this, each leaf was excised, and the petiole was removed. Individual leaflets were used for species with compound leaves. We used a scanner to scan fresh leaves at 300 d.p.i. resolution, and the ImageJ (National Institutes of Health) to measure the leaf area. Leaves were then oven-dried at 80 °C for at least 48 h to a constant value, and dry weight was measured with a balance with a precision of 0.0001 g (Mettler Toledo, AL204, Shanghai, China).
We measured leaf thickness (LT, μm) with paraffin-embedded leaf tissue sections. This process included the following steps: dehydration, wax immersion, embedding, sectioning to a thickness of 8–12 μm, safranin staining and sealing. We then used a light microscope (Leica Microsystems Ltd, Leica DM2500) with a mounted digital camera to take images at 50×, 100×, 200× and 400× magnification (2560 × 1920 pixels). Five images of each slide were taken at each magnification. We then used ImageJ software (National Institutes of Health) to determine the LT. Leaf density (LD, kg m⁻³) was calculated as 1/(SLA × LT).

Five samples of 20-cm Tygon tube (14-171-219, Saint-Gobain Tygon S3 TM 3603 Flexible Tubings, Fisher Scientific, USA) or silicone tube (8060-0030, NalgeneTM 50 Platinum-cured Silicone Tubing, Thermo Scientific, USA) was utilized in weight measurement. Weight of the tubes prior to infusion were measured with an Analytical Balance (AL204, Analytical Balance, Mettler Toledo, Germany). After the measurement of the initial weights, the tubes were submerged in silicone oil (DMS-T15, polydimethylsiloxane, trimethylsiloxy, 50 cSt, GelestSInc, USA) and weighed at designated time points. For each time point, tubes were removed from the oil with forceps and held vertically for 30 s for the excess silicone oil to flow out of the tube. The bottoms of the tubes were then gently dabbed with Kimwipes (Kimwipe, Kimberly-Clark Corp., USA). After measurement, the tubes were again submerged in silicone oil until the next time point. Tubes were measured every 3 hr for the first 2 days; every 6 hr from days 3 to 6; and every 24 hr from day 6 and onwards. Measurements were taken until data showed no significant increase, and that the plateau trendline consist of at least three data points. Based on these data, for all the protein- and microbial-binding assays, silicone catheters were submerged in silicone oil for 5 days prior to use to ensure full infusion.

In the early morning (3:30–5:00) and at noon (11:30–13:00) (both local times) on consecutive sunny days, the water content (WC) and water potential (ψ) were determined. The branches were collected from the middle and upper parts of the canopy on the sunny side, and the ψ of each time period was measured (three times for each branch) using the WP4C Dewpoint Potential Meter. At the same time as ψ determination, the assimilation branches and their corresponding secondary branches (the definition of branch rank) were classified following Strahler’s system (Mcmahon and Kronauer 1976 ). The terminal is the zeroth-grade branch of the current year, and the downward branch is, in turn, the first-grade branch. An appropriate amount of sample was separated and cut from different branches and placed a 1/10 000 precision balance (AL204, METTLER TOLEDO, CHN) to determine the fresh weight (FW). Samples were placed in envelope bags and numbered. They were exposed to sunlight for 4 h in the field and brought back to the laboratory after finishing. Finally, they were dried in an oven at 75 °C for 48 h and weighed to determine the DW. Water content was calculated as follows: WC = (FW − DW)/FW.

The solar vapor generation experiment was performed by using a 300 W xenon lamp (CEL-S500/350, CEAULIGHT, Beijing, China) as simulated sunlight. The light intensity was adjusted by tuning the distance between light source and material surface to ensure the output of 1 kW m⁻² (one standard sunlight) irradiation. The light intensity was measured with a solar power meter (CEL-FZ-A). HCC of 3 mm thickness was cut into rectangular pieces with an area of 4 cm × 1.5 cm, and each piece was put on top of a PS foam of the same size. Mass loss caused by water evaporation under 1 kW m⁻² sunlight was measured using an electronic balance (AL204, METTLER TOLEDO, Shanghai, China) at 10-min intervals. The environment temperature was maintained at 20 °C, and relative humidity was ~60%. All evaporation rates were measured after a stabilization period of 30 min. The solar–vapor conversion efficiency (η) was calculated using Formula (3) [27 (link)]: $$\eta =\frac{\dot{m}{H}_{\mathrm{e}}}{P_0}$$
where $\dot{m}$ is the mass flux (after subtracting the mass flux of water evaporation under dark environment), H_e is the equivalent evaporation enthalpy of HCC in pure water, which was calculated as shown in Formula (4) below [18 (link)], and P₀ is the solar radiation power (1 kW m⁻²).
$$U_{\mathrm{in}}=H_{\mathrm{v}}{m}_0=H_{\mathrm{e}}{m}_{\mathrm{g}}$$
where $U_{\mathrm{in}}$ is the identical power input, H_v and m₀ are the evaporation enthalpy and mass change in bulk water, and m_g is the mass change in HCC.

The DESs were prepared by direct mixing of salts and HBDs according to the specified molar ratio. Each salt was mixed with the corresponding HBD using magnetic stirring at 400 rpm and 353.15 K until a homogenous transparent liquid is formed. Afterward, the mixture was placed in a moisture-controlled area to cool down at room temperature. The weight of the materials was determined by analytical balance (Mettler Toledo AL204) with the standard uncertainty of 10⁻⁴ g. The water content of all DESs was determined by Karl-Fischer titration analysis (Aquamax Karl-Fischer titration, GR Scientific Ltd.), resulting in mass fractions of < 1200 ± 100 ppm for all DESs. The DESs prepared with different salt to HBD molar rations are summarized in Table 2.