DOI: 10.5061/dryad.4mw6m90gg
title: Fifteen physiological traits related to osmoregulation and reactive oxygen species metabolism in two life form aquatic plants under a natural water salinity gradient on the Tibetan Plateau and Northwest China

description: Aquatic plants, as the primary producers, determine the community
 structure and ecological function of freshwater ecosystems. However,
 salinization threatens inland freshwater wetlands and thus the survival of
 aquatic plants. Exploring the plant physiological responses to increasing
 water salinity could enhance our understandings of plant adaptive
 strategies under future climate change regimes in wetlands. We measured 15
 physiological traits of 49 aquatic plant species along a large
 environmental gradient in alpine and arid regions of western China, to
 explore the physiological adaptions and compare the similarities and
 differences in adaptive strategies between the two life forms to natural
 water salinity. We found that both water salinity and low temperature were
 key factors affecting aquatic plants in alpine and arid regions. Aquatic
 plants adapt to saline habitats by accumulating proline and sulfur (S)
 concentrations, and to cold habitats by increasing ascorbate peroxidase
 activity. Plant trait network analysis showed that the hub trait in
 emergent plants was S, but in submerged plants was proline, suggesting
 that emergent plants balanced osmoregulation and reactive oxygen
 metabolism via S-containing compounds, while submerged plants prioritizing
 the regulation of osmotic balance via proline.
description: We first bottled 500 ml water
 from an intermediate depth below the water surface for laboratory
 analysis. Three sediment columns were dug randomly from the upper 0-20 cm
 under the water-sediment interface and then mixed as the sediment sample
 for each site. All sediment samples were air-dried, ground, and sieved
 through a 0.15 mm sieve for further analysis. In total, we investigated
 178 sites, including 90 sites on the Tibetan Plateau and 88 sites in
 the Northwest Region. We measured the
 salinity of undisturbed water in situ using a hand-held multi-parameter
 meter (PROPLUS, YSI, USA). The total Cl<sup>-</sup>,
 SO<sub>4</sub><sup>2-</sup>,
 Na<sup>+</sup>, K<sup>+</sup>,
 Mg<sup>2+</sup>, and Ca<sup>2+</sup> contents in
 water were determined by an ion chromatograph (ICS-1000, DIONEX, USA).
 The total Ca, K, Mg, and Na
 concentrations in sediments were measured by inductively coupled plasma
 mass spectrometer (ICPMS-2030, Shimadzu, Japan) using the samples from the
 field, and the total
 sediment S concentration was measured by the elemental analyzer (UNICUBE,
 Elementar, Germany).
 Two life forms of aquatic plants were sampled.
 Different sampling methods were adopted according to different plant life
 forms. For emergent plants, 30-50 fully expanded and intact leaves were
 randomly selected for each species. For submerged plants, we collected
 30-50 segments of the plants (20 cm from the tip) and then removed all
 leaves from these segments. All plant samples of each species were divided
 into two parts: one for elemental measurements after oven dried at 70°C
 for 72 h and the other part for measuring the plant physiological traits
 using fresh samples that have been frozen by liquid nitrogen in the
 field. In total, we collected 527 plant samples (251 on the Tibetan
 Plateau and 276 in the Northwest Region) belonging to 49 species across
 the whole study area. The frozen fresh leaves were used to determine
 the contents of proline, soluble protein, soluble sugar, and glutathione
 (GSH), and the activity of ascorbate peroxidase (APX), catalase (CAT),
 peroxidase (POD) and superoxide dismutase (SOD) in plants. Detailed
 methods for measuring the traits were described in Supplementary
 materials. Oven-dried
 plant samples were used to measure the element concentrations in plants.
 The samples were ground to powder and divided into two parts: one for
 measuring total plant S concentrations by Vario MACRO cubic elemental
 analyzer (UNICUBE Elementar, Germany), and the other for total Calcium
 (Ca), Potassium (K), Magnesium (Mg) and Sodium (Na) concentrations by
 inductively coupled plasma mass spectrometer (ICPMS-2030, Shimadzu
 Japan).
description: # Fifteen physiological traits related to osmoregulation and reactive
 oxygen species metabolism in two life form aquatic plants under a natural
 water salinity gradient on the Tibetan Plateau and Northwest China Leaf
 physiological traits of aquatic plants in western China In total, we
 collected 49 species for a total of 527 samples ("data.xlsx").
 All 527 samples were used to determine 15 physiological traits including:
 chlorophyll (Chl), proline (Pro), soluble protein (SP), soluble sugar
 (SS), anthocyanin (Anth), ascorbate peroxidase (APX), catalase (CAT),
 glutathione (GSH), peroxidase (POD), superoxide dismutase (SOD), calcium
 (Ca), potassium (K), magnesium (Mg), sodium (Na), and sulfur (S). ##
 Description of the data and file structure We have three sheets in this
 dataset file. In sheet 1, we described the environmental variables for
 each site. In sheet 2, we have a 528*24 matrix. The abbreviations for
 variables: Variable Description GSP Growing season precipitation mm GST
 Mean growing season temperature () W_Sal Water salinity () W_Cl Total
 chloride ion content in water (mg L-1) W_SO4 Total sulphate ion content in
 water (mg L-1) W_Ca Total calcium ion content in water (mg L-1) W_K Total
 potassium ion content in water (mg L-1) W_Mg Total magnesium ion content
 in water (mg L-1) W_Na Total sodium ion content in water (mg L-1) S_Ca
 Total calcium concentration in sediments (mg g-1) S_K Total potassium
 concentration in sediments (mg g-1) S_Mg Total magnesium concentration in
 sediments (mg g-1) S_Na Total sodium concentration in sediments (mg g-1)
 S_S Total sulphur concentration in sediments (mg g-1) ENV1 The first
 principal component in the results of the principal component analysis of
 the environmental factors, representing the water parameters. ENV2 The
 second principal component in the results of the principal component
 analysis of the environmental factors, representing the climate
 parameters. ENV3 The third principal component in the results of the
 principal component analysis of the environmental factors, representing
 the sediment parameters. Chl chlorophyll (ug cm-2) Pro proline (ug g-1) SP
 soluble protein (ug g-1) SS soluble sugar (mmol g-1) Anth anthocyanin APX
 ascorbate peroxidase (U g-1) CAT catalase (U g-1) GSH glutathione (mg g-1)
 POD peroxidase (U g-1) SOD superoxide dismutase (U g-1) Ca Leaf Calcium
 Concentrations (mg g-1) K Leaf Potassium Concentrations (mg g-1) Mg Leaf
 Magnesium Concentrations (mg g-1) Na Leaf Sodium Concentrations (mg g-1) S
 Leaf Sulfur Concentrations (mg g-1)