Asymmetric Effects of Temperature Change on Herbaceous Seed Germination: Implications for Climate Warming

Seed germination is a critical ecological process that governs both the establishment and maintenance of plant diversity and is highly sensitive to temperature fluctuations. As climate change accelerates, particularly through increasing temperatures, the disruption to seed germination could pose sig...

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Bibliographic Details
Main Authors: Kai Chen, Zi-Hong Chen, Zhong-Hua Jiang
Format: Article
Language:English
Published: MDPI AG 2024-10-01
Series:Diversity
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Online Access:https://www.mdpi.com/1424-2818/16/10/649
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Summary:Seed germination is a critical ecological process that governs both the establishment and maintenance of plant diversity and is highly sensitive to temperature fluctuations. As climate change accelerates, particularly through increasing temperatures, the disruption to seed germination could pose significant risks to plant diversity. Therefore, understanding how temperature fluctuations affect seed germination is essential for predicting the future recruitment of mountain plants and for conserving biodiversity in the context of ongoing climate warming scenarios. In this study, we collected seeds from 14 <i>Impatiens</i> species (Balsaminaceae) in the Gaoligong Mountains (Southwest China) at an elevation of approximately 2000 m. Germination tests were conducted on seeds subjected to cold stratification (42 days at 4 °C) across a range of alternating temperatures (6/1, 11/6, 16/11, 21/16, 26/21, and 31/26 °C). We used generalized linear mixed-effects models (random intercept) with temperature and its higher-order terms as the fix-effect terms to construct four models describing the relationship between germination percentage and temperature. Results indicated that (1) the germination percentage varied significantly among species and temperature treatments; (2) the nonlinear and asymmetrical model, incorporating temperature and its quadratic and cubic terms, best fit the germination data; and (3) the decline in germination percentage above the optimum temperature (T<sub>o</sub>) was significantly steeper than the increase below based on the best model. Overall, these findings suggest that seed plants at low elevations in mountain ecosystems may be particularly vulnerable to future climate warming due to the sharp decline in germination percentage at temperatures above T<sub>o</sub>. Thus, protecting low-elevation plants should be a key priority in biodiversity conservation efforts as global temperatures continue to rise.
ISSN:1424-2818