BACKGROUND One of the most extreme environments on our planet is the Maritime Antarctic territory, due to its low-water availability, which restricts the development of plants. Sanionia uncinata Hedw. (Amblystegiaceae), the main colonizer of the Maritime Antarctic, has effective mechanisms to tolerate this environment. It has been described that the tolerance to desiccation is mediated by the hormone abscisic acid (ABA), antioxidants systems, accumulation of compatible solutes and proteins of the late embryogenesis abundant (LEA). However, to date, these mechanisms have not been described in S. uncinata. Therefore, in this work, we postulate that the tolerance to desiccation in the Antarctic moss S. uncinata is mediated by the accumulation of ABA, the osmolytes proline and glycine betaine, and dehydrins (an LEA class 11 proteins). To demonstrate our hypothesis, S. uncinata was subjected to desiccation for 24 h (loss in 95% of water content), and the effects on its physiological, photosynthetic, antioxidant and biochemical parameters were determined. RESULTS Our results showed an accumulation of ABA in response to water loss, and the activation of protective responses that involves an increment in levels of proline and glycine betaine, an increment in the activity of antioxidant enzymes such as SOD, CAT, APX and POD, and the accumulation of dehydrins proteins. CONCLUSION The results showed, suggest that S. uncinata is a desiccation-tolerant moss, property mediated by high cellular plasticity regulated by ABA.

中文翻译：

---

南极苔藓 Sanionia uncinata 的干燥耐受性。


背景技术我们星球上最极端的环境之一是南极海域，由于其水资源匮乏，限制了植物的发育。 Sanionia uncinata Hedw. （Amblystegiaceae）是南极海域的主要殖民者，具有有效的机制来忍受这种环境。据描述，对干燥的耐受性是由脱落酸（ABA）激素、抗氧化剂系统、相容性溶质的积累和胚胎发生晚期丰富蛋白（LEA）介导的。然而，迄今为止，这些机制尚未在 S. uncinata 中得到描述。因此，在这项工作中，我们假设南极苔藓 S. uncinata 对干燥的耐受性是由 ABA、渗透剂脯氨酸和甘氨酸甜菜碱以及脱水素（LEA 11 类蛋白质）的积累介导的。为了证明我们的假设，将 S. uncinata 干燥 24 小时（损失 95% 的水分），并确定对其生理、光合作用、抗氧化和生化参数的影响。结果我们的结果显示，ABA 因失水而积累，保护性反应的激活涉及脯氨酸和甘氨酸甜菜碱水平的增加，以及 SOD、CAT、APX 和 POD 等抗氧化酶活性的增加，和脱水蛋白的积累。结论 结果表明，S. uncinata 是一种耐干燥苔藓，其特性是由 ABA 调节的高细胞可塑性介导的。