Kranner Ilse
Institute of Plant Physiology, University of Graz Schubertstraße 51, A-8010 Graz, Austria.
New Phytol. 2002 May;154(2):451-460. doi: 10.1046/j.1469-8137.2002.00376.x.
• Glutathione-related mechanisms of coping with desiccation were studied in three lichens (Pseudevernia furfuracea, Peltigera polydactyla and Lobaria pulmonaria) with different degrees of tolerance. Reduced (GSH) and oxidised glutathione (GSSG), glutathione reductase (GR) and glucose-6-phosphate dehydrogenase (G6PDH) were measured during short- and long-term desiccation, and subsequent rehydration. • Glutathione was analysed by HPLC, and enzymes by spectrophotometry. Lichens were desiccated over silica gel, and rehydrated either in liquid water or water vapour. • Desiccation caused oxidation of almost all of the GSH. After short-term desiccation, rehydration caused rapid reduction of GSSG in all three species. Following long-term desiccation, P. furfuracea (the most desiccation-tolerant lichen studied) rapidly increased GSH when rehydrated in liquid water or water vapour. However, in P. polydactyla, neither method of rehydration re-established the initial GSH pool. After long-term desiccation, L. pulmonaria regenerated initial concentrations of GSH only when rehydrated in liquid water. • Reduction of GSSG was correlated with re-establishment of the predesiccation activity of G6PDH, a key enzyme of the oxidative pentose shunt. This enzyme probably provides NADPH during the first stages of rehydration, when photosynthesis is not yet possible.
• 研究了三种具有不同耐受程度的地衣（毛云杉叶苔、多指皮果衣和肺衣）中与谷胱甘肽相关的应对干燥的机制。在短期和长期干燥以及随后的复水过程中，测定了还原型谷胱甘肽（GSH）、氧化型谷胱甘肽（GSSG）、谷胱甘肽还原酶（GR）和葡萄糖-6-磷酸脱氢酶（G6PDH）。
• 通过高效液相色谱法分析谷胱甘肽，通过分光光度法分析酶。地衣在硅胶上干燥，并在液态水或水蒸气中复水。
• 干燥导致几乎所有的GSH氧化。短期干燥后，复水使所有三个物种中的GSSG迅速还原。长期干燥后，毛云杉叶苔（所研究的最耐干燥的地衣）在液态水或水蒸气中复水时，GSH迅速增加。然而，在多指皮果衣中，两种复水方法都未能重新建立初始的GSH库。长期干燥后，肺衣只有在液态水中复水时才会再生初始浓度的GSH。
• GSSG的还原与氧化戊糖支路的关键酶G6PDH干燥前活性的重新建立相关。这种酶可能在复水的最初阶段提供NADPH，此时光合作用尚不可能进行。
