supporting files for "What to Choose for Estimating Leaf Water Status - Spectral Reflectance or in vivo Chlorophyll Fluorescence?"

Fig. 1 Workflow and parameters used for comparative analysis.

Fig. 2 Representative spectra of diffusive reflectance measured on the adaxial side (R_D) of fresh (RWC = 98%), partially desiccated (RWC = 52% or 54%) and severely desiccated leaves (RWC = 5%) of tobacco (A) and barley (E). Comparison of R_D and R_B (R from the abaxial leaf side) in fresh and severely desiccated leaves of tobacco (B) and barley (F). Water index (WI = R₉₀₀/R₉₇₀) and relative decrease of R in the 800-1100 nm region (ΔR) estimated from R_D (indexed by "D") and R_B (indexed by "B") in desiccating leaves of tobacco (C, D) and barley (G, H).

Fig. 3 Water index (WI_SWIR = R₁₀₀₀/R₁₄₅₀) estimated from measurement of directional R from adaxial side of desiccating leaf samples of tobacco (A) and barley (B).

Fig. 4 Equivalent water thickness (EWT) during desiccation of tobacco and barley leaf samples within the RWC interval 100-50%.

Fig. 5 Normalized difference vegetation index (NDVI = (R₇₈₀-R₆₃₀)/(R₇₈₀+R₆₃₀)) estimated from measurement of diffusive R from the abaxial (NDVI_B) and adaxial side (NDVI_D) of desiccating leaves of tobacco (A) and barley (D). SPAD-values of desiccating leaves of tobacco (B) and barley (E). Relative SPAD and NDVI΄_D (estimated from measurement of directional R from the adaxial side) of a representative leaf of tobacco (C) and barley (F) during its desiccation (in % of the value measured immediately after leaf detachment). For selected data points, the time after the leaf detachment is indicated.

Fig. 6 Chlorophyll fluorescence parameters of desiccating tobacco and barley leaf samples. (A, D) The maximum quantum yield of PSII photochemistry in the dark-adapted state (F_V/F_M) and the effective quantum yield of PSII photochemistry in the light-adapted state (ΦPSII_st). (B, E) The non-photochemical quenching of chlorophyll fluorescence after 1 min of exposure to actinic light (NPQ₁). (C, F) The non-photochemical quenching of chlorophyll fluorescence at steady state (NPQ_st).

Fig. 7 Coefficient of reliability (CR), coefficient of sensitivity (CS) and coefficient of inaccuracy (CI) of parameters measured in desiccating leaf samples of tobacco and barley within the RWC interval 100-50%. The parameters have been divided into 5 groups according to the type of leaf characteristics they reflect. A horizontal line in CR plot indicates the reliability threshold (CR = 0.4).

Table 1 Parameters measured on desiccating tobacco and barley leaves ranked according to the value of their coefficient of reliability (CR) within the RWC interval 100-50% and the corresponding values of the coefficient of determination (R²).

Fig. S1 Decrease in relative water content (RWC) of leaf samples of tobacco and barley with time after their detachment

Fig. S2 Micrographs of leaf structure of fresh tobacco (A) and barley (B) leaves.

Fig. S3 WI_SWIR images of representative desiccating tobacco and barley leaf samples. Numbers above the samples indicate their RWC in %.

Fig. S4 (A) Leaf area (in % of the area of fresh leaves) and (B) equivalent water thickness (EWT) during desiccation of tobacco and barley leaf samples.

Fig. S5 Imaging of chlorophyll fluorescence parameters of representative desiccating tobacco and barley leaf samples. The maximum quantum yield of PSII photochemistry (F_V/F_M), the effective quantum yield of PSII photochemistry in the light-adapted state (ΦPSII_st), the non-photochemical quenching of chlorophyll fluorescence after 1 min of exposure to actinic light (NPQ₁), and the non-photochemical quenching of Chl fluorescence at steady state (NPQ_st).

Fig. S6 Dependencies of measured parameters on RWC (in interval 100-50%) in desiccating tobacco leaves and segments. The parameters are ranked from most to least reliable according to their coefficient of reliability (CR). All parameters are normalized to their mean value (ȳ).

Fig. S7 Dependencies of measured parameters on RWC (in interval 100-50%) in desiccating barley leaves and segments. The parameters are ranked from most to least reliable according to their coefficient of reliability (CR). All parameters are normalized to their mean value (ȳ).

Fig. S8 Leaf water potential measured by psychrometry (Ψ_psy) and by pressure chamber (Ψ_press) in desiccating leaves of tobacco (A) and barley (B).

Table S1 Parameters measured on desiccating leaf samples ranked according to their coefficient of sensitivity (CS) within the RWC interval 100-50% in tobacco and barley.

Table S2 Parameters measured on desiccating leaf samples ranked according to their coefficient of inaccuracy (CI) within the RWC interval 100-50% in tobacco and barley.

Table S3 Ranking of measured parameters according to their coefficient of reliability (CR), sensitivity (CS) and inaccuracy (CI) in desiccating leaf samples of tobacco and barley within the RWC interval 100-50%. The parameters have been divided into 5 groups (the first column) according to the type of leaf characteristics they reflect.

Table S4 Approximate time required for the measurement of the parameters used in the study and the destructiveness/non-destructiveness of the measurement. The parameters that were used for the comparison according to their coefficients of reliability (CR), sensitivity (CS) and inaccuracy (CI) are written in bold.

Fig. 2_spectra of diffusive reflectance - source data for each panel (A-H) of Fig. 2: Representative spectra of diffusive reflectance measured on the adaxial side (R_D) of fresh (RWC = 98%), partially desiccated (RWC = 52% or 54%) and severely desiccated leaves (RWC = 5%) of tobacco (A) and barley (E). Comparison of R_D and R_B (R from the abaxial leaf side) in fresh and severely desiccated leaves of tobacco (B) and barley (F). Water index (WI = R₉₀₀/R₉₇₀) and relative decrease of R in the 800-1100 nm region (ΔR) estimated from R_D (indexed by "D") and R_B (indexed by "B") in desiccating leaves of tobacco (C, D) and barley (G, H).

Fig.3_water index WISWIR - source data for each panel (A+B) of Fig. 3: Water index (WISWIR = R1000/R1450) estimated from measurement of directional R from adaxial side of desiccating leaf samples of tobacco (A) and barley (B).

Fig.4_equivalent water thickness - source data for Fig. 4: Equivalent water thickness (EWT) during desiccation of tobacco and barley leaf samples within the RWC interval 100-50%.

Fig.5_NDVI - source data for each panel (A-F) of Fig. 5: Normalized difference vegetation index (NDVI = (R780-R630)/(R780+R630)) estimated from measurement of diffusive R from the abaxial (NDVIB) and adaxial side (NDVID) of desiccating leaves of tobacco (A) and barley (D). SPAD-values of desiccating leaves of tobacco (B) and barley (E). Relative SPAD and NDVI΄D (estimated from measurement of directional R from the adaxial side) of a representative leaf of tobacco (C) and barley (F) during its desiccation (in % of the value measured immediately after leaf detachment).

Fig.6_chlorophyll fluorescence parameters - source data for each panel (A-F) of Fig. 6: Chlorophyll fluorescence parameters of desiccating tobacco and barley leaf samples. (A, D) The maximum quantum yield of PSII photochemistry in the dark-adapted state (FV/FM) and the effective quantum yield of PSII photochemistry in the light-adapted state (ΦPSIIst). (B, E) The non-photochemical quenching of chlorophyll fluorescence after 1 min of exposure to actinic light (NPQ1). (C, F) The non-photochemical quenching of chlorophyll fluorescence at steady state (NPQst).

Fig.7_coefficients of reliability, sensitivity, inaccuracy - Coefficient of reliability (CR), coefficient of sensitivity (CS) and coefficient of inaccuracy (CI) of parameters measured in desiccating leaf samples of tobacco and barley within the RWC interval 100-50%.

Fig.S1_relative water content - source data for supplementary Fig. 1: Relative water content (RWC) of leaf samples of tobacco and barley with time after their detachment.

Fig.S4_leaf area and equivalent water thickness - source data for supplementary Fig. 4: Leaf area (A) and equivalent water thickness (EWT; B) during desiccation of tobacco and barley leaf samples.

Fig.S6_dependencies of parameters on RWC in tobacco - source data for each panel (A-N) of supplementary Fig.6: Dependencies of measured parameters (water potential, NPQ, NDVI, reflectance, SPAD, Fv/Fm, water indexes) on RWC (in interval 100-50%) in desiccating tobacco leaves and segments.

Fig.S7_dependencies of parameters on RWC in barley - source data for each panel (A-N) of supplementary Fig.7: Dependencies of measured parameters (water potential, NPQ, NDVI, reflectance, SPAD, Fv/Fm, water indexes) on RWC (in interval 100-50%) in desiccating barley leaves and segments.

Fig.S8_leaf water potential - source data for supplementary Fig. 8: Leaf water potential measured by psychrometry (Ψpsy) and by pressure chamber (Ψpress) in desiccating leaves of tobacco (A) and barley (B).