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

IF 3.1 2区环境科学与生态学 Q2 ECOLOGY

Oikos Pub Date : 2024-01-11 DOI:10.1111/oik.10181

Shi-Jian Yang, Yong-Jiang Zhang, Ya Zhang, Jun-Chu Peng, Cai-Yan Liu, Da-Wei Li, Wen Guo

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引用次数: 0

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.

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耐寒性差异促进了中国西南地区二倍体和多倍体猕猴桃沿海拔梯度的生态位分化

据推测，多倍体可提高寒冷地区植物的抗冻性。然而，多倍体抗冻能力所涉及的适应策略和关键生理机制仍不清楚。在猕猴桃（Actinidia chinensis）中，四倍体和六倍体的栖息地海拔较高，气候较二倍体寒冷，这为研究细胞型之间抗冻性分化的机制提供了一个研究系统。我们对其自然分布区的环境条件进行了描述，并沿海拔梯度在每个细胞型的典型地点测量了叶片的冷害特征和水分关系。多倍体的半致死温度（LT50）低于冰核温度（INT），这反映了它们应对高原地区冰冻事件的耐受策略。多倍体的负张力损失点更多，细胞弹性模量更大，这有助于减轻冰冻引起的细胞脱水造成的损害，从而增强其对较低零下温度（较低的LT50）的耐受性。多倍体的过冷能力（较低的 INT）增强，可能与细胞外冰形成较少有关，这是因为细胞在充分收缩时的渗透势、凋亡水分数和组织电容较低。我们的研究发现，多倍体猕猴桃比二倍体猕猴桃更耐寒，这表明耐寒性与水分关系之间存在潜在联系。综上所述，抗逆性的这种差异可能是多倍体植物向恶劣环境转移的原因。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Oikos 环境科学-生态学

CiteScore

6.20

自引率

5.90%

发文量

152

审稿时长

6-12 weeks

期刊介绍： Oikos publishes original and innovative research on all aspects of ecology, defined as organism-environment interactions at various spatiotemporal scales, so including macroecology and evolutionary ecology. Emphasis is on theoretical and empirical work aimed at generalization and synthesis across taxa, systems and ecological disciplines. Papers can contribute to new developments in ecology by reporting novel theory or critical empirical results, and "synthesis" can include developing new theory, tests of general hypotheses, or bringing together established or emerging areas of ecology. Confirming or extending the established literature, by for example showing results that are novel for a new taxon, or purely applied research, is given low priority.