气候宽容度的变化，但不是气孔特征，部分解释了禾本科草物种的分布。
Variation in climatic tolerance, but not stomatal traits, partially explains Pooideae grass species distributions.
机构信息
The University of Vermont, Department of Plant Biology, Burlington, VT 05405, USA.
出版信息
Ann Bot. 2021 Jul 28;128(1):83-95. doi: 10.1093/aob/mcab046.
BACKGROUND AND AIMS
Grasses in subfamily Pooideae live in some of the world's harshest terrestrial environments, from frigid boreal zones to the arid windswept steppe. It is hypothesized that the climate distribution of species within this group is driven by differences in climatic tolerance, and that tolerance can be partially explained by variation in stomatal traits.
METHODS
We determined the aridity index (AI) and minimum temperature of the coldest month (MTCM) for 22 diverse Pooideae accessions and one outgroup, and used comparative methods to assess predicted relationships for climate traits versus fitness traits, stomatal diffusive conductance to water (gw) and speed of stomatal closure following drought and/or cold.
KEY RESULTS
Results demonstrate that AI and MTCM predict variation in survival/regreening following drought/cold, and gw under drought/cold is positively correlated with δ 13C-measured water use efficiency (WUE). However, the relationship between climate traits and fitness under drought/cold was not explained by gw or speed of stomatal closure.
CONCLUSIONS
These findings suggest that Pooideae distributions are at least partly determined by tolerance to aridity and above-freezing cold, but that variation in tolerance is not uniformly explained by variation in stomatal traits.
背景和目的
禾本科黍亚科的植物生活在世界上一些最恶劣的陆地环境中，从寒冷的北方地区到干旱多风的草原。据推测，该组内物种的气候分布是由其对气候的耐受差异所驱动的，而这种耐受性可以部分解释为气孔特征的变化。
方法
我们确定了 22 种不同的禾本科黍亚科植物及其一个外群的干旱指数 (AI) 和最冷月最低温度 (MTCM)，并采用比较方法评估了气候特征与适应力特征（包括气孔导度对水的扩散性 (gw) 和干旱/寒冷后的气孔关闭速度）之间的预测关系。
主要结果
结果表明，AI 和 MTCM 可以预测干旱/寒冷后植物的存活/复绿情况，干旱/寒冷下的 gw 与通过 δ¹³C 测量的水分利用效率 (WUE) 呈正相关。然而，干旱/寒冷下气候特征与适应力之间的关系不能通过 gw 或气孔关闭速度来解释。
结论
这些发现表明，禾本科黍亚科的分布至少部分取决于对干旱和冰点以上寒冷的耐受性，但对干旱和寒冷的耐受性的变化不能通过气孔特征的变化来均匀解释。
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