DOI: 10.5061/dryad.t4b8gtj9s
title: Data from: Anatomical traits explain drought response of seedlings from wet tropical forests

description: Water availability regulates plant community dynamics, but the drought
 response of seedlings remains poorly known despite their vulnerability,
 especially for the Asian tropics. In particular, discerning how functional
 traits of seedlings mediate drought response can aid generalizable
 predictions of tree responses to global environmental change. We assessed
 interspecific variation in drought response explained by above- and
 below-ground seedling traits. We conducted a dry-down experiment in the
 greenhouse using 16 tree species from the humid forests of Western Ghats
 in southern India, chosen to represent differences in affinity to
 conditions of high and low seasonal drought (seasonality affiliation). We
 compared survival, growth, and photosynthetic performance under drought
 and well-watered conditions, and assessed the extent to which species’
 responses were explained by seasonality affiliation and 12 traits of root,
 stem, and leaf. We found that the species from seasonally dry forest
 reduced photosynthetic rate in drought compared to well-watered
 conditions, but seasonality affiliation did not explain differences in
 growth and survival. Performance in drought vs well-watered conditions
 were best explained by anatomical traits of xylem, veins and stomata.
 Species with larger xylem reduced their growth and photosynthesis to
 tolerate desiccation. In drought, species with smaller stomata correlated
 with lower survival even though photosynthetic activity decreased by a
 larger extent with larger stomata. Overall, anatomical traits of xylem and
 stomata, directly related to water transport and gas-exchange, played a
 more prominent role than commonly used traits (e.g., specific leaf area,
 leaf dry matter content) in explaining species response to drought, and
 may offer a good proxy for physiological traits related to drought
 tolerance of seedlings. --
description: ### File: Metadata_Jhaveri_etal-drought_traits_10Jan2024.pdf
 Description: File containing metadata in tabular format for quick
 reference ### File:
 DATA_GrowthRatesTraits_2024Jhaverietal-drought_traits_EcoEvo.csv
 Description: Seedling heights in their first week of being included in the
 experiment, and their height at the end of the experiment. Growth rate and
 Relative growth rates are calculated using the initial and final heights
 of each individual. #### Variables Sr.: serial number SPECIES: Species
 Short form for the 16 species included in the experiment: ACTMAL =
 *Actinodaphne malabarica* * ARTHET = *Artocarpus heterophyllus* * APOLIN =
 *Aporosa lindleyana* * DIOANG = *Diospyros angustifolia* * ELASER =
 *Elaeocarpus serratus* * ELATUB = *Elaeocarpus tuberculatus* * GARIND =
 *Garcinia indica* * GARTAL = *Garcinia talbotii* * HOLGRA = *Holigarna
 grahamii* * MYRMAL = *Myristica malabarica* * OLEDIO = *Olea dioica* *
 PALELL = *Palaquium ellipticum* * PERMAC = *Persea macrantha* * SYZCAR =
 *Syzygium caryophyllatum* * SYZCUM = *Syzygium cumini* * SYZGAR =
 *Syzygium gardneri*. species_code: Unique id for each seedling. A
 combination of entries from columns block_code + treatment + Species +
 individual number. block_code: Experimental block B1 – B6 treatment:
 Experimantal treatments; C = Control treatment, D = drought treatment
 week_num.x: week number of experiment start for each seedling, (always 1)
 stem_height.x: stem height at the start of experiment. Unit = centimeter
 (cm.) week_num.y: week number of experiment end for each seedling
 stem_height.y: stem height at the end of experiment. Unit = centimeter
 (cm.) delta_grth: stem height difference (stem_height.y–stem_height.x).
 Unit = centimeter (cm.) grth_rate: growth rate per week (delta_grth /
 week_num.y). Unit = centimeter per week (cm. week ^-1^) RGR: relative
 growth rate (grth_rate / stem_height.x). Unit = centimeter per week per
 initial height (cm. week ^-1^ cm. ^-1^) MEAN_SLA: mean Specific leaf area
 (SLA) for species. Unit = centimeter square per grams (cm.^2 g.^-1). NA =
 missing data (data missing for APOLIN) MEAN_LDMC: mean leaf dry matter
 content (LDMC) for species. Unit = Micrometer per milligram (μm mg ^-1^).
 NA = missing data (data missing for APOLIN) MEAN_SS: mean stomatal size
 (SS) for species. Unit = Micrometer square (μm.^2^). NA = missing data
 (data missing for APOLIN) MEAN_SL: mean stomatal length (SL) for species.
 Unit = Micrometer (μm.). NA = missing data (data missing for APOLIN)
 MEAN_XD: mean xylem diameter (XD) for species. Unit = Micrometer (μm.). NA
 = missing data (data missing for APOLIN) MEAN_SD: mean stomatal density
 (SD) for species. Unit = number of stomata per centimeter (number cm.
 ^-2^) MEAN_VD: mean vein density (VD) for species. Unit = number of vein
 per centimeter (number cm. ^-2^) MEAN_RL: mean root length (RL) for
 species. Unit = millimeter (mm.). NA = missing data (data missing for
 APOLIN and DIOANG) MEAN_RA: mean root area (RA) for species. Unit =
 millimeter square (mm.^2^). NA = missing data (data missing for APOLIN and
 DIOANG) MEAN_RD: mean root diameter (RD) for species. Unit = millimeter
 (mm.). NA = missing data (data missing for APOLIN and DIOANG) MEAN_SRL:
 mean specific root length (SRL) for species. Unit = centimeter per grams
 (cm. g. ^-1^). NA = missing data (data missing for APOLIN and DIOANG)
 MEAN_RF: mean root mass fraction (RF) for species. Unit = gram of root per
 gram of whole plant (g. g. ^-1^) SI: Seasonality index (SI) for species.
 Index values extracted from Krishnadas, M., M. Sankaran, N. Page, J.
 Joshi, S. Machado, N. Nataraj, S. K. Chengappa, V. Kumar, A. Kumar, and R.
 Krishnamani. 2021. Seasonal drought regulates species distributions and
 assembly of tree communities across a tropical wet forest region A. Hampe
 (Ed.). Glob. Ecol. Biogeogr. geb.13350. Available at:
 [https://onlinelibrary.wiley.com/doi/10.1111/geb.13350](https://onlinelibrary.wiley.com/doi/10.1111/geb.13350). MEAN_SA: Mean Stomatal area fraction (SAF) for species. Unit = SD * SS * 10 ^-8^ per centimeter of leaf (cm.^2^ cm. ^-2^). NA = missing data (data missing for APOLIN) ### File: Photosynthesis_traits_2024Jhaverietal-drought_traits_EcoEvo.csv Description: Photosynthesis was measured monthly using a LiCOR 6400XT for seedlings of all species from control and drought treatments. Photosynthesis rates were measured with a 2x3 cm2 leaf chamber. The chamber conditions were maintained at PAR 1500 µmolm-2s-1, 65 % humidity, 400 µmols-1 flow rate, fan speed at 10,000 RPM. Measurements were taken between 0700 - 1200 hours. #### Variables Sr.: Serial number SPECIES: Species Short form for the 16 species included in the experiment: * ACTMAL = *Actinodaphne malabarica* * ARTHET = *Artocarpus heterophyllus* * APOLIN = *Aporosa lindleyana* * DIOANG = *Diospyros angustifolia* * ELASER = *Elaeocarpus serratus* * ELATUB = *Elaeocarpus tuberculatus* * GARIND = *Garcinia indica* * GARTAL = *Garcinia talbotii* * HOLGRA = *Holigarna grahamii* * MYRMAL = *Myristica malabarica* * OLEDIO = *Olea dioica* * PALELL = *Palaquium ellipticum* * PERMAC = *Persea macrantha* * SYZCAR = *Syzygium caryophyllatum* * SYZCUM = *Syzygium cumini* * SYZGAR = *Syzygium gardneri*. species_code: Unique id for each seedling. A combination of entries from columns block_code + treatment + Species + individual number. block_code: Experimental block B1 – B6 treatment: Experimantal treatments; C = Control treatment, D = drought treatment date: date of photosynthesis reading n_week: number of week since the start of experiment photosynthesis_rate: photosynthesis rate (As.) Unit = micromoles of Carbon-dioxide per meter square of leaf per second (μ mol CO2 m ^-2^ s ^-1^) MEAN_SLA: mean Specific leaf area (SLA) for species. Unit = centimeter square per grams (cm.^2^ g. ^-1^). NA = missing data (data missing for APOLIN) MEAN_LDMC: mean leaf dry matter content (LDMC) for species. Unit = Micrometer per milligram (μm mg ^-1^). NA = missing data (data missing for APOLIN) MEAN_SS: mean stomatal size (SS) for species. Unit = Micrometer square (μm.^2^). NA = missing data (data missing for APOLIN) MEAN_SL: mean stomatal length (SL) for species. Unit = Micrometer (μm.). NA = missing data (data missing for APOLIN) MEAN_XD: mean xylem diameter (XD) for species. Unit = Micrometer (μm.). NA = missing data (data missing for APOLIN) MEAN_SD: mean stomatal density (SD) for species. Unit = number of stomata per centimeter (number cm. ^-2^) MEAN_VD: mean vein density (VD) for species. Unit = number of vein per centimeter (number cm. ^-2^) MEAN_RL: mean root length (RL) for species. Unit = millimeter (mm.). NA = missing data (data missing for APOLIN and DIOANG) MEAN_RA: mean root area (RA) for species. Unit = millimeter square (mm.^2^). NA = missing data (data missing for APOLIN and DIOANG) MEAN_RD: mean root diameter (RD) for species. Unit = millimeter (mm.). NA = missing data (data missing for APOLIN and DIOANG) MEAN_SRL: mean specific root length (SRL) for species. Unit = centimeter per grams (cm. g. ^-1^). NA = missing data (data missing for APOLIN and DIOANG) MEAN_RF: mean root mass fraction (RF) for species. Unit = gram of root per gram of whole plant (g. g. ^-1^) SI: Seasonality index (SI) for species. Index values extracted from Krishnadas, M., M. Sankaran, N. Page, J. Joshi, S. Machado, N. Nataraj, S. K. Chengappa, V. Kumar, A. Kumar, and R. Krishnamani. 2021. Seasonal drought regulates species distributions and assembly of tree communities across a tropical wet forest region A. Hampe (Ed.). Glob. Ecol. Biogeogr. geb.13350. Available at: [https://onlinelibrary.wiley.com/doi/10.1111/geb.13350](https://onlinelibrary.wiley.com/doi/10.1111/geb.13350). MEAN_SA: Mean Stomatal area fraction (SAF) for species. Unit = SD * SS * 10 ^-8^ per centimeter of leaf (cm.^2^ cm. ^-2^). NA = missing data (data missing for APOLIN) ### File: survival_traits_2024Jhaverietal-drought_traits_EcoEvo.csv Description: Seedling survival at the end of the experiment was recored as alive = 1 and dead = 0. For 14 species the experiment ended at 16th week number but for Aporosa lindleyana and Diospyros angustifolia the experiment lasted only 12 weeks due COVID-19 restrictions. #### Variables Sr.: Serial number SPECIES: Species Short form for the 16 species included in the experiment: * ACTMAL = *Actinodaphne malabarica* * ARTHET = *Artocarpus heterophyllus* * APOLIN = *Aporosa lindleyana* * DIOANG = *Diospyros angustifolia* * ELASER = *Elaeocarpus serratus* * ELATUB = *Elaeocarpus tuberculatus* * GARIND = *Garcinia indica* * GARTAL = *Garcinia talbotii* * HOLGRA = *Holigarna grahamii* * MYRMAL = *Myristica malabarica* * OLEDIO = *Olea dioica* * PALELL = *Palaquium ellipticum* * PERMAC = *Persea macrantha* * SYZCAR = *Syzygium caryophyllatum* * SYZCUM = *Syzygium cumini* * SYZGAR = *Syzygium gardneri*. species_code: Unique id for each seedling. A combination of entries from columns block_code + treatment + Species + individual number. treatment: Experimantal treatments; C = Control treatment, D = drought treatment week_num: week of experiment end DOA: Survival at the end of experiment entered as 1 = alive and 0 = dead block_code: Experimental block B1 – B6 MEAN_SLA: mean Specific leaf area (SLA) for species. Unit = centimeter square per grams (cm.^2 g.^-1). NA = missing data (data missing for APOLIN) MEAN_LDMC: mean leaf dry matter content (LDMC) for species. Unit = Micrometer per milligram (μm mg ^-1^). NA = missing data (data missing for APOLIN) MEAN_SS: mean stomatal size (SS) for species. Unit = Micrometer square (μm.^2^). NA = missing data (data missing for APOLIN) MEAN_SL: mean stomatal length (SL) for species. Unit = Micrometer (μm.). NA = missing data (data missing for APOLIN) MEAN_XD: mean xylem diameter (XD) for species. Unit = Micrometer (μm.). NA = missing data (data missing for APOLIN) MEAN_SD: mean stomatal density (SD) for species. Unit = number of stomata per centimeter (number cm. ^-2^) MEAN_VD: mean vein density (VD) for species. Unit = number of vein per centimeter (number cm. ^-2^) MEAN_RL: mean root length (RL) for species. Unit = millimeter (mm.). NA = missing data (data missing for APOLIN and DIOANG) MEAN_RA: mean root area (RA) for species. Unit = millimeter square (mm.^2^). NA = missing data (data missing for APOLIN and DIOANG) MEAN_RD: mean root diameter (RD) for species. Unit = millimeter (mm.). NA = missing data (data missing for APOLIN and DIOANG) MEAN_SRL: mean specific root length (SRL) for species. Unit = centimeter per grams (cm. g. ^-1^). NA = missing data (data missing for APOLIN and DIOANG) MEAN_RF: mean root mass fraction (RF) for species. Unit = gram of root per gram of whole plant (g. g. ^-1^) SI: Seasonality index (SI) for species. Index values extracted from Krishnadas, M., M. Sankaran, N. Page, J. Joshi, S. Machado, N. Nataraj, S. K. Chengappa, V. Kumar, A. Kumar, and R. Krishnamani. 2021. Seasonal drought regulates species distributions and assembly of tree communities across a tropical wet forest region A. Hampe (Ed.). Glob. Ecol. Biogeogr. geb.13350. Available at: [https://onlinelibrary.wiley.com/doi/10.1111/geb.13350](https://onlinelibrary.wiley.com/doi/10.1111/geb.13350). MEAN_SA: Mean Stomatal area fraction (SAF) for species. Unit = SD * SS * 10 ^-8^ per centimeter of leaf (cm.^2^ cm ^-2^). NA = missing data (data missing for APOLIN)