DOI: 10.5061/dryad.t76hdr89r
title: Data from: Extreme warming coordinately shifts root and leaf traits of alpine plants towards conservatism

description: Climate change-induced shifts in plant functional traits can profoundly
 affect the stability of plant communities and ecosystem functions.
 However, the way in which leaf and root traits coordinate in response to
 climate extremes remains poorly understood. Here we measured sixteen leaf
 and root traits of ten dominant plant species from a Tibetan alpine
 grassland to explore whether extreme warming leads to coupled/decoupled
 responses of root and leaf traits. We found that extreme warming increased
 the investment in defensive traits of plant leaves, but this came at the
 expense of plant growth. Specifically, warming increased the concentration
 of defensive compounds (tannin) in leaves by 44.4% but decreased leaf mass
 by 12.3%. More importantly, we found that the changes in leaf and root
 traits in response to extreme warming were coupled, resulting in both
 systems adopting more conservative strategies. For instance, extreme
 warming reduced leaf area and simultaneously increased root tissue
 density. Trait network analysis further supported this view, showing that
 extreme warming increased root edge density and decreased leaf modularity,
 indicating a more integrated network of leaf and root traits to enhance
 resource utilization efficiency. Our findings suggest that extreme warming
 may drive a coupled shift toward more conservative traits in both leaves
 and roots within alpine grasslands, with significant implications for
 predicting future ecosystem dynamics under escalating climate extremes.
description: <strong><em>Species culture and laboratory-controlled
 extreme warming experiment</em></strong> In
 August 2020, a survey was conducted in the alpine meadows at Haibei
 Station to assess biomass and identify dominant species based on relative
 biomass abundance. From May to August 2021, seeds from over 30 common
 species were collected for germination. Based on survey and pre-experiment
 results, 10 dominant plant species were selected for the experiment,
 including 2 types of grasses (<em>Stipa aliena</em> and
 <em>Elymus nutans</em>), 2 types of sedges (<em>Carex
 alatauensis</em> and <em>Carex buchananii</em>), 2 types
 of legumes (<em>Tibetia himalaica</em> and <em>Oxytropis
 ochrocephala</em>), and 4 types of forbs (<em>Saussurea
 superba</em>, <em>Saussurea nigrescens</em>,
 <em>Gentiana straminea</em> and <em>Aster
 diplostephioides</em>), which together accounted for 48.54% of the
 total biomass. In our laboratory-controlled extreme
 warming experiment, spanning one growing season (from May to September),
 we employed temperature gradient plates (Model GRD-1; Grant Scientific
 Inc., Cambridgeshire, UK) to apply both control and warming treatments.
 The control treatment incubator was set to 16 °C, while the extreme
 warming treatment was set to 20 °C (+4°C, &gt; 2δ). Each species had
 three replicates per treatment, with 4-6 plants per pot. In total, 60 pots
 were used. To minimize the potential impact of pot position on
 experimental outcomes, the pots were randomly repositioned every ten days
 throughout the study. To simulate the effects of extreme temperatures on
 soil moisture, all plants received ample water during the first month of
 growth. Following this period, watering was reduced to once every 20 days.
 The light cycle, consisted of 16 hours of light and 8 hours of darkness,
 simulated the growing season conditions as Haibei Alpine Grassland
 Ecosystem Research Station.
 <strong><em>Plant functional trait
 measurements</em></strong> In our study, we
 monitored 16 morphological and chemical traits. The net photosynthetic
 rate (shortened as Photo) was measured using a portable Li-6800
 photosynthesis system (Li-cor, USA), and chlorophyll content (SPAD) was
 assessed with a SPAD-502Plus chlorophyll meter (Konica-Minolta, Japan).
 Root exudates were collected following Phillips<em> et
 al.</em> (2011) with minor modifications. After selecting healthy
 plants with intact root systems, removed residual soil and organic
 matters, then placed the roots in a hydroponic system to collect exudates.
 The collected liquid was filtered through a 0.45 μm membrane within 2-4
 hours and stored at -20 ℃. The root exudation rate (RE, μg C⁻¹ g root
 biomass h⁻¹) was determined by measuring total organic carbon with a TOC
 analyzer (Multi N/C 3000, Analytikjena, Germany) using 15 mL of collected
 liquid. Next, fine roots (&lt; 2 mm in diameter)
 and leaves were randomly selected for measurement of morphological traits.
 Roots were scanned with an Epson Expression 10000XL Scanner (Epson,
 Japan), and leaves were scanned with a portable Li-3000 leaf area meter
 (Li-cor, USA). Scanned images were analyzed for leaf area (LA), average
 diameter of fine root, fine root length, surface area, and fine root
 volume using WINRHIZO software (Regent Instruments Inc., Canada). Both
 leaves and roots were dried at 105°C for 30 minutes, then at 75 °C for 48
 hours to a constant weight. The dried samples were weighted to calculate
 specific leaf area (SLA), leaf dry matter content (LM), specific root
 length (SRL), specific root area (SRA), and root tissue density
 (RTD). For measurement of chemic traits, the leaf and
 root samples were milled. Carbon and nitrogen contents of leaves (LC, LN)
 and roots (RC, RN) were measured using an elemental analyzer (CHNS/O,
 Leeman, Italy). Leaf tannin content (Tannin) was determined by shaking 1-2
 g of dried leaf sample in an acetone solution for 30-40 minutes, filtered,
 analyzed absorbance spectrophotometrically, and then calculated from a
 standard curve where tannic acid concentration served as X-axis and
 absorbance values as Y-axis. Leaf lignin content (Lignin) was measured
 using a lignin detection kit, with the spectrophotometer preheated for 30
 minutes and set to 280 nm, using acetic acid as the zero
 reference.
description: # Dataset for "Extreme warming coordinately shifts root and leaf
 traits of alpine plants towards conservatism" #### File:
 New_data-Extreme_warming_coordinately_shifts_root_and_leaf_traits_of_alpine_plants_towards_conservatism_.xlsx **Description:** This dataset contains leaf and root traits values of 10 species we chose in our research. ##### Variables * Species: The Latin names of 10 species * Genus: Genus of 10 species * Family: Family of 10 species * Treatment: Control (16℃) or Extreme warming (+4=20℃) * LC: Leaf carbon content (%) * LN: Leaf nitrogen content (%) * LA: Leaf area (cm2) * LM: Leaf mass (g) * SLA: Specific leaf area (cm2 g-1) * Photo: Net photosynthetic rate (µmol m-2 s-1) * SPAD: Relative value of chlorophyll content in leaf (%) * Lignin: Lignin content (mg g-1) * Tannin: Tannin content (mg kg-1) * SRL: Specific root length (m g-1) * SRA: Specific root area (cm2 g-1) * RTD: Root tissue density (g cm3) * RC: Root carbon content (%) * RN: Root nitrogen content (%) * RE: Root exudation rate (μg C⁻¹ g root biomass h⁻¹) * RSR: Root shoot ratio