Induction of desiccation tolerance mechanisms occurs in both the fast-drying filmy fern Crepidomanes inopinatum and the slow-drying fern Loxogramme abyssinica
Induction of desiccation tolerance mechanisms occurs in both the fast-drying filmy fern Crepidomanes inopinatum and the slow-drying fern Loxogramme abyssinica
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DOI：
10.1016/j.sajb.2020.02.014
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发表时间：
2020-07
影响因子：
3.1
通讯作者：
K.G.W. Mkhize;F. Minibayeva;R. Beckett
中科院分区：
文献类型：
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作者：
K.G.W. Mkhize;F. Minibayeva;R. Beckett
耐干燥蕨类（crepidomanes inopinatumandLoxogramme abyssinicca）通常生长在夸祖鲁-纳塔尔省非洲山区森林的林下。凤尾蕨（Crepidomanes inopinatumis）是一种“薄膜状”蕨类植物，由于缺乏角质层而干燥迅速；contrastL。阿比西尼亚有角质层，因此干得很慢。据预测，因为c。由于生长速度快，该物种几乎没有时间诱导DT机制，因此主要依赖本构机制。相比之下，干燥缓慢的l。阿比西尼亚有时间将DT机制落实到位，因此可能更多地依赖于诱导机制。在这里，我们测试了干燥-再水合循环是否诱导了两种通常被认为有助于DT的机制，特别是两种活性氧（ROS）清除酶的活性和可溶性糖浓度的增加。叶绿素荧光参数测量表明，两种植物在干燥后的复水化过程中恢复迅速，证实了它们都是真正的多水化植物。在这两个物种中，缓慢的干燥增加了活性氧清除酶超氧化物歧化酶（SOD）的活性和可溶性糖的浓度。干燥对两种植物的活性氧清除酶过氧化物酶（POX）活性几乎没有影响，这表明维持POX活性是一种基本的DT机制。然而，两种植物之间的主要区别是，脱驯化发生在膜蕨；在阴凉昏暗光线下潮湿存放一周，可降低DT。相反，在有角质层的蕨类植物中没有发生脱驯化。然而，总的来说，结果表明与我们最初的假设相反，即使在快速干燥的薄膜蕨类植物中也存在诱导DT机制。
The desiccation tolerant (DT) fern speciesCrepidomanes inopinatumandLoxogramme abyssinicaoften grow together in the understory of KwaZulu-Natal Afromontane forests.Crepidomanes inopinatumis a “filmy” fern that dries rapidly because it lacks a cuticle; by contrastL. abyssinicapossesses a cuticle, and therefore dries slowly. It was predicted that becauseC. inopinatumdries quickly, this species would have little time available to induce DT mechanisms, and therefore mainly relies on constitutive mechanisms. By comparison, the slow-dryingL. abyssinicahas time to put DT mechanism in place, and therefore may depend more on inducible mechanisms. Here we tested whether a drying-rehydration cycle induces two mechanisms often suggested to contribute DT, specifically increases in the activity of two reactive oxygen species (ROS) scavenging enzymes and the concentration of soluble sugars. Measurement of chlorophyll fluorescence parameters showed that both species recover rapidly during rehydration after desiccation, confirming that both are genuinely poikilohydric. In both species slow desiccation increased the activity of the ROS scavenging enzyme superoxide dismutase (SOD), and the concentrations of soluble sugars. Desiccation had little effect on the activity of the (ROS) scavenging enzyme peroxidases (POX) in either species, suggesting that maintenance of POX activity is a constitutive DT mechanism. However, the main difference between the two species was that de-acclimation occurred in the filmy fern; moist storage under cool dim light for a week reduced DT. By contrast, in the fern with a cuticle no de-acclimation occurred. However, overall, results suggest that counter to our original hypothesis, inducible DT mechanisms occur even in filmy ferns that desiccate rapidly.