Divergence in cold tolerance promotes niche differentiation between diploid and polyploid kiwifruits along an altitudinal gradient in Southwest China

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 ..., 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., , # Divergence in cold tolerance promotes niche differentiation between diploid and polyploid kiwifruits along an altitudinal gradient in Southwest China

## 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 data...

多倍化（polyploidization）被认为可提升寒冷地区植物的抗冻能力。然而，多倍体抗冻能力所涉及的适应性策略与关键生理机制仍未明确。在中华猕猴桃（Actinidia chinensis，俗称猕猴桃）中，四倍体（tetraploids）与六倍体（hexaploids）的生境海拔高于二倍体（diploids），气候也更为寒冷，这为探究不同细胞型（cytotypes）间抗冻性分化的机制提供了研究体系。我们对各细胞型自然分布区的环境条件进行了表征，并沿海拔梯度在典型样地测定了叶片水平的冷害性状与水分关系指标。多倍体的半致死温度（semi-lethal temperature, LT50）低于冰核温度（ice nucleation temperature, INT），这反映了其应对高原地区冻害的耐受策略。多倍体具有更负的膨压丧失点与更大的细胞弹性模量，可缓解由……引发的损伤。我们测定了3种典型细胞型（2x、4x和6x）猕猴桃的叶片胞外冰核温度（INT）。我们采用电解质渗漏法与叶绿素荧光法，评估了离体叶片的细胞膜与叶绿体膜冻害程度。我们获取了相对电导率（relative electrical conductivity, REC）与相对叶绿素荧光（relative chlorophyll fluorescence, RCF），并据此得到了50%相对电导率对应的叶片致死温度（LT50-REC）以及基于相对叶绿素荧光的叶片半致死温度（LT50-RCF）。采用台面脱水法测定了叶片压力-容积（pressure-volume, P-V）曲线，并计算了相关参数。每个细胞型选取5个个体开展上述生理指标测定。
# 抗冻性分化促进中国西南地区二倍体与多倍体猕猴桃沿海拔梯度的生态位分化

## 摘要
本数据集包含作者实测的原始数据。研究发现，多倍体的半致死温度（LT50）低于冰核温度（INT）。多倍体更负的膨压丧失点与更大的细胞弹性模量，可缓解冻害引发的细胞脱水损伤。多倍体的过冷能力（supercooling capacity）增强（INT更低），这可能与其全膨压时的渗透势更低、质外体水分占比（apoplastic water fraction）与组织电容（tissue capacitance）更小导致的胞外冰生成量更少有关。

## 使用说明
本数据集包含3种猕猴桃细胞型（2x、4x、6x）的分布信息，以及各细胞型典型样地的叶片水平冷害性状与水分关系指标。各数据集的详细说明见README文件。
数据……