Post-burning regeneration of the Chaco seasonally dry forest: germination response of dominant species to experimental heat shock
Post-burning regeneration of the Chaco seasonally dry forest: germination response of dominant species to experimental heat shock
复制标题
查科季节性干旱森林的燃烧后再生：优势物种对实验热激的萌发反应
作者：
Pedro Jaureguiberry;S. Díaz
据推测，阿根廷中部查科季节性干燥森林的植物物种进化压力很小，无法形成特殊的火灾反应特征，如热刺激萌发。然而，其他历史因素，如季节性干旱和/或内生孢子虫的扩散，可能会导致一些物种产生耐热种子。因此，耐热萌发应该比热刺激或热敏感萌发更常见。为了测试这一点，我们将来自查科地区的26个优势物种的种子暴露在广泛的实验热处理中，并在25摄氏度和12小时的光周期下培养30天。然后，我们对它们的发芽率进行评分，并根据它们在热处理后相对于对照的萌发情况，将它们划分为热刺激、耐热或热敏感三类。17种植物表现出耐热萌发，包括所有土生禾本科植物。在较低强度的热处理下，有7种植物表现出热刺激萌发。只有两种植物表现出对热敏感的萌发。内生动物对种子萌发反应无影响。我们认为，与地中海气候生态系统不同，火不是查科森林发展的主要进化力量，我们的结果有助于更好地了解查科植物群落在面临日益频繁的火灾时的潜在反应。
Plant species of the Chaco seasonally dry forest of central Argentina have presumably been under a low evolutionary pressure to develop specialized fire-response traits, such as heat-stimulated germination. Nevertheless, other historical factors such as seasonal drought and/or endozoochorus dispersal could have led some species to develop heat-tolerant seeds. Therefore, heat-tolerant germination should be more common than heat-stimulated or heat-sensitive germination. To test this, we exposed seeds of 26 dominant species from the Chaco region to a broad range of experimental heat treatments and incubated them for 30 days at 25 °C and 12 h photoperiod. We then scored the percent germination and classified them as heat-stimulated, heat-tolerant or heat-sensitive based on their germination following heat treatments relative to control. Seventeen species showed heat-tolerant germination, including all native graminoids. Seven species showed heat-stimulated germination, under the less-intense heat treatments. Only two species showed heat-sensitive germination. Endozoochory had no influence on germination responses. We suggest that, unlike Mediterranean-climate ecosystems, fire was not a major evolutionary force in the development of Chaco forests, and our results provide greater understanding of the potential response of Chaco plant communities in the face of increasingly frequent fires.
DOI：
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发表时间：
2015-10
期刊：
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影响因子：
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作者：
Douglas M. Bates;M. Maechler;Ben Bolker;Steven C. Walker
通讯作者：
Douglas M. Bates;M. Maechler;Ben Bolker;Steven C. Walker