Desiccation tolerance of Sphagnum revisited: a puzzle resolved
Desiccation tolerance of Sphagnum revisited: a puzzle resolved
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DOI：
10.1111/plb.12126
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发表时间：
2014-07-01
期刊：
影响因子：
3.9
通讯作者：
Vicherova, E.
中科院分区：
文献类型：
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作者：
Hajek, T.;Vicherova, E.
作为生态系统工程师，泥炭藓通过保水、酸化和泥炭积累来控制周围环境。由于保水避免干燥，泥炭藓一般不耐干旱;然而，泥炭藓干燥耐受性（DT）的文献提供了令人困惑的结果，表明其DT的诱导性质。为了测试这一点，通过（i）缓慢干燥;（ii）施加阿坝和（iii）冷却或霜冻使各种泥炭藓属物种和其他中位苔藓植物对干旱硬化。DT耐受性评估为严重干燥后叶绿素荧光参数的恢复。我们监测的季节性过程中DT沼泽brittes。在实验室条件下，初始去硬化后，未经处理的泥炭藓芽缺乏DT，然而，DT诱导的所有硬化处理，除了冷却，特别是缓慢干燥，并在泥炭藓物种的部分Cuspidata。在该领域，水藻在洼地和草坪开发DT几次在生长季节，响应降水量减少和地下水位降低。Hummock和水生物种开发DT仅在深秋，可能是作为对霜冻的反应。泥炭藓protonemata未能开发DT，因此，干燥可能会限制泥炭藓建立在干燥的栖息地与合适的基板化学。脱水避免水苔之间形成紧凑的丘或生活淹没，因此，他们不发展DT在外地，缺乏最初的干燥经验，这是经常在空心和草坪栖息地。我们证实了形态-生理权衡：与典型的中空泥炭藓相比，丘状物种在保水（避免干燥）方面投入更多的资源，而它们发展生理DT的能力较低。
As ecosystem engineers, Sphagnum mosses control their surroundings through water retention, acidification and peat accumulation. Because water retention avoids desiccation, sphagna are generally intolerant to drought; however, the literature on Sphagnum desiccation tolerance (DT) provides puzzling results, indicating the inducible nature of their DT. To test this, various Sphagnum species and other mesic bryophytes were hardened to drought by (i) slow drying; (ii) ABA application and (iii) chilling or frost. DT tolerance was assessed as recovery of chlorophyll fluorescence parameters after severe desiccation. We monitored the seasonal course of DT in bog bryophytes. Under laboratory conditions, following initial de-hardening, untreated Sphagnum shoots lacked DT; however, DT was induced by all hardening treatments except chilling, notably by slow drying, and in Sphagnum species of the section Cuspidata. In the field, sphagna in hollows and lawns developed DT several times during the growing season, responding to reduced precipitation and a lowered water table. Hummock and aquatic species developed DT only in late autumn, probably as a response to frost. Sphagnum protonemata failed to develop DT; hence, desiccation may limit Sphagnum establishment in drier habitats with suitable substrate chemistry. Desiccation avoiders among sphagna form compact hummocks or live submerged; thus, they do not develop DT in the field, lacking the initial desiccation experience, which is frequent in hollow and lawn habitats. We confirmed the morpho-physiological trade-off: in contrast to typical hollow sphagna, hummock species invest more resources in water retention (desiccation avoidance), while they have a lower ability to develop physiological DT.