Schipperges B, Rydin H
Department of Ecological Botany, Uppsala University, Villavägen 14, S-752 36 Uppsala, Sweden.
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New Phytol. 1998 Dec;140(4):677-684. doi: 10.1046/j.1469-8137.1998.00311.x.
The response of photosynthetic CO exchange to tissue water content in five spp. of Sphagnum from contrasting microhabitats (S. fuscum (Schimp.) Klinggr., S. papillosum H. Lindb., S. magellanicum Brid., S. balticum (Russ.) C. Jens. and S. cuspidatum Ehrh. ex Hoffm.) was measured in the laboratory using an infrared gas analyser technique. Experiments were designed to test recovery of net photosynthesis after periodic and long lasting desiccation. The contact between capitula and basal parts of the mosses seems to be important for survival. Isolated capitula cut off from any contact with the water table were not able to recover after complete desiccation (at 15°C for 2-4 d). When contact with the water table is lost, e.g. during long periods of desiccation, recovery of net photosynthesis can take place but only if the water content of the capitula does not fall too far below c. 10-20% of the water content at compensation point. There was no relationship between the ability of net photosynthesis to recover from desiccation and the wetness of the natural microhabitat. Sphagna survive dry periods by avoidance of drying out by high capillarity or dense growth form (as in S. fuscum).
利用红外气体分析仪技术在实验室中测定了来自不同微生境的5种泥炭藓（fuscum泥炭藓（Schimp.）Klinggr.、乳头泥炭藓H. Lindb.、麦哲伦泥炭藓Brid.、波罗的海泥炭藓（Russ.）C. Jens.和尖叶泥炭藓Ehrh. ex Hoffm.）光合CO交换对组织含水量的响应。实验旨在测试周期性和长期干燥后净光合作用的恢复情况。泥炭藓的头状体与基部之间的接触似乎对其存活很重要。与地下水位完全失去接触的分离头状体在完全干燥后（15℃下干燥2 - 4天）无法恢复。当与地下水位失去接触时，例如在长时间干燥期间，净光合作用仍可恢复，但前提是头状体的含水量不会降至补偿点含水量的约10 - 20%以下太多。净光合作用从干燥中恢复的能力与自然微生境的湿度之间没有关系。泥炭藓通过高毛细作用或密集生长形式（如fuscum泥炭藓）避免干燥来度过干旱期。
