Fern Stomatal Responses to ABA and CO2 Depend on Species and Growth Conditions
Fern Stomatal Responses to ABA and CO2 Depend on Species and Growth Conditions
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DOI：
10.1104/pp.17.00120
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发表时间：
2017-06-01
期刊：
影响因子：
7.4
通讯作者：
Merilo, Ebe
中科院分区：
文献类型：
--
作者：
Horak, Hanna;Kollist, Hannes;Merilo, Ebe
大气中二氧化碳水平、气候和空气湿度的变化会影响植物的气体交换，这种交换是由气孔控制的，气孔是植物叶片和茎上由保护细胞形成的小气孔。在过去的4亿年里，进化塑造了气孔运动的形态和调节机制，以适应各种陆地植物群的需要。气孔关闭是对植物激素脱落酸（ABA）、二氧化碳浓度升高和空气湿度降低的响应。在这些刺激下控制气孔关闭的主动调节机制是否已经存在于苔藓这种最古老的具有气孔的植物群体中，或者是最近在被子植物中获得的，仍然存在争议。有人认为，蕨类植物和石松植物等基部维管植物的气孔完全是水被动关闭的。另一方面，在一些苔藓、石松和蕨类植物中发现了响应ABA和CO2的主动气孔关闭。本研究表明，两种温带蕨类植物的气孔对ABA和CO2有响应，一些蕨类植物的气孔对空气湿度降低有积极的调节机制。重要的是，蕨类植物的气孔响应取决于生长条件。这些数据表明，蕨类植物的气孔行为比以前预期的要复杂，一些蕨类植物存在积极的气孔调节，而另一些蕨类植物可能已经失去了气孔调节。为了深入了解陆地植物气孔响应的进化，需要进一步分析蕨类植物的种类、生活史、进化年龄和生长条件。
Changing atmospheric CO2 levels, climate, and air humidity affect plant gas exchange that is controlled by stomata, small pores on plant leaves and stems formed by guard cells. Evolution has shaped the morphology and regulatory mechanisms governing stomatal movements to correspond to the needs of various land plant groups over the past 400 million years. Stomata close in response to the plant hormone abscisic acid (ABA), elevated CO2 concentration, and reduced air humidity. Whether the active regulatory mechanisms that control stomatal closure in response to these stimuli are present already in mosses, the oldest plant group with stomata, or were acquired more recently in angiosperms remains controversial. It has been suggested that the stomata of the basal vascular plants, such as ferns and lycophytes, close solely hydropassively. On the other hand, active stomatal closure in response to ABA and CO2 was found in several moss, lycophyte, and fern species. Here, we show that the stomata of two temperate fern species respond to ABA and CO2 and that an active mechanism of stomatal regulation in response to reduced air humidity is present in some ferns. Importantly, fern stomatal responses depend on growth conditions. The data indicate that the stomatal behavior of ferns is more complex than anticipated before, and active stomatal regulation is present in some ferns and has possibly been lost in others. Further analysis that takes into account fern species, life history, evolutionary age, and growth conditions is required to gain insight into the evolution of land plant stomatal responses.