Divergence in cold tolerance promotes niche differentiation between diploid and polyploid kiwifruits along an altitudinal gradient in Southwest China
Data files
Dec 20, 2023 version files 33.85 KB
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README.md
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Yang_et_al_2023_Oikos_dataset.xlsx
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Abstract
Polyploidization is hypothesized to improve the freezing resistance of plants in cold regions. However, adaptive strategies and key physiological mechanisms involved in the freezing resistant ability of polyploids remain unclear. In Actinidia chinensis (kiwifruits), the tetraploids and hexaploids occupy higher altitude habitats with colder climates than the diploids, providing a study system to investigate mechanisms responsible for differentiation in freezing resistance between cytotypes. We characterized environmental conditions of their natural distribution areas, and measured leaf-level traits of cold damages and water relations at typical sites of each cytotype along an altitudinal gradient. Polyploids showed lower semi-lethal temperature (LT50) than ice nucleation temperature (INT), reflecting a tolerance strategy to cope with freezing events in the plateau regions. More negative turgor loss points and larger cell elastic modulus of polyploids could help to alleviate damages from freezing-induced cell dehydration, thus strengthening their tolerance to lower subzero temperatures (lower LT50). The increased supercooling capacity of polyploids (lower INT) might correlate with less extracellular ice formation due to lower osmotic potential at full turgor, apoplastic water fraction and tissue capacitance. Our study uncovers a greater cold tolerance in polyploid kiwifruits than diploids, and suggests the potential linkage between freezing tolerance and water relations. Taken together, such a divergence in stress resistance may underlie the niche shift of polyploid plants towards harsh environments.
https://doi.org/10.5061/dryad.4f4qrfjkb
Abstract
These data contents include the primary data that measured by the authors. We found that polyploids showed lower semi-lethal temperature (LT50) than ice nucleation temperature (INT). More negative turgor loss points and larger cell elastic modulus of polyploids could help to alleviate damages from freezing-induced cell dehydration. The increased supercooling capacity of polyploids (lower INT) might correlate with less extracellular ice formation due to lower osmotic potential at full turgor, apoplastic water fraction and tissue capacitance.
Usage notes
These datasets were included the distribution information of the three cytotypes (2x, 4x and 6x) of kiwifruits, leaf-level traits of cold damages and water relations at typical sites of each cytotype.
Details for each dataset are provided in the README file.
The datasets included:
1) locality points
Number of samples (Code)
Cytotype (2x, 4x, 6x)
Longitude (E) and Latitude (E) of each samples
2) electrical conductivity of leaves (leaf EC)
For the three cytotypes (2x, 4x and 6x), electrical conductivity (EC, μS cm-1) measurements for the leaf samples (unboiled and boiled samples) under different target temperature treatments (20, 0, -5, -10, -15, and -20 ℃).
3) leaf relative chlorophyll fluorescence (leaf RF)
For the three cytotypes (2x, 4x and 6x), chlorophyll fluorescence measurements (the Fv /Fm value) for the leaf samples under different target temperature treatments (20, 0, -5, -10, -15, and -20 ℃).
4) leaf INT and LT50
For the three cytotypes (2x, 4x and 6x), leaf extracellular ice nucleation temperature (INT, ℃), leaf lethal temperature at 50 % REC (LT50-REC, ℃) and leaf semi-lethal temperature by RCF (LT50-RCF, ℃) were determined.
5) leaf P-V
The eight related parameters were obtained from leaf pressure-volume (P-V) curves.
πtlp (MPa): leaf water potential at turgor loss point; πo (MPa): osmotic potential at full turgor; af: apoplastic water fraction; Cft (MPa-1): capacitance at full turgor; Cft* (mol m-2 MPa-1): absolute capacitance at full turgor; SWC: saturated water content; RWCtlp (%): relative water content at turgor loss point; ε (MPa): bulk modulus of elasticity.
Additional details are available in the datasets.
We measured leaf extracellular ice nucleation temperature (INT) of three typical cytotypes (2x, 4x and 6x) of kiwifruits. The electrolyte leakage and chlorophyll fluorescence measurements were used to assess freezing damage on the cellular and chloroplast membranes of detached leaves. We obtained the relative electrical conductivity (REC) and relative chlorophyll fluorescence (RCF), then got leaf lethal temperature at 50 % REC (LT50-REC) and leaf semi-lethal temperature by RCF (LT50-RCF). The determination of leaf pressure-volume (P-V) curves and calculation for related parameters were obtained using the bench dehydration technique. Five individuals per cytotype were used for the above physiological measurements.