密集的叶子冷却促进树木在创纪录的热浪期间的生存
Bradley C Posch1,2, Susan E Bush1, Dan F Koepke1
1Department of Research, Conservation and Collections, Desert Botanical Garden, Phoenix, AZ 85008.
概括
极端的热浪损害了森林. 即使是短暂的土壤水损失也会破坏树叶的冷却,导致树叶的损坏和死亡,特别是来自凉爽气候的基因型.
科学领域:
- 植物生理学 植物生理学
- 生态生态学 生态生态学
- 气候变化生物学
背景情况:
- 森林生态系统面临着全球热浪带来的越来越大的威胁.
- 叶子的热调节和耐受性对于植物在极端高温期间的生存至关重要.
- 叶子的热调节和热浪期间的水供应之间的相互作用仍然不清楚.
研究的目的:
- 调查土壤水量对叶子热调节和热浪期间*Populus fremontii*基因型的生存的影响.
- 了解水压下的热和液压安全之间的生理性权衡.
- 为了比较不同气候来源的基因型对热量和水压力的反应.
主要方法:
- 在创纪录的热浪 (>48°C) 期间,对 *Populus fremontii* 基因型进行了受控的普通花园实验.
- 操纵土壤水的可用性 (非限制与72小时的减少).
- 测量叶子温度,叶子水潜力和叶子死亡率.
主要成果:
- 非水限制条件允许基因型冷却叶子在空气温度以下25°C.
- 一个72小时的土壤水减少破坏了叶子的冷却,导致叶子温度超过空气温度和生理损伤值.
- 所有基因型在水应激后都经历了显著的叶子死亡率,来自温暖气候的基因型显示出更好的热调节和较低的死亡率.
结论:
- 短暂的土壤水限制严重扰乱了Populus fremontii*的叶子热调节,在极端高温期间危及了其生存.
- 叶子热和液压安全之间的权衡在水应力下出现.
- 热量和水应激反应的基因型变异突显了原始气候对预测森林弹性的重要性.
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