Kobayashi T, Natanani N, Hirakawa T, Suzuki M, Miyake T, Chiwa M, Yuhara T, Hashimoto N, Inoue K, Yamamura K, Agus N, Sinogaya J R, Nakane K, Kume A, Arakaki T, Sakugawa H
Japan Science and Technology Corporation (CREST), Center for Forest Decline Studies, Hiroshima Technoplaza, Higashi-Hiroshima.
Environ Pollut. 2002;118(3):383-91. doi: 10.1016/s0269-7491(01)00289-5.
The hydroxyl radical (*OH) is generated in polluted dew on the needle surfaces of Japanese red pine (Pinus densiflora Sieb. et Zucc.). This free radical, which is a potent oxidant, is assumed to be a cause of ecophysiological disorders of declining trees on the urban-facing side of Mt. Gokurakuji, western Japan. Mists of *OH-generating N(III) (HNO2 and NO2-) and HOOH + Fe + oxalate solutions (50 and 100 microM, pH 5.1-5.4) simulating the dew water were applied to the foliage of pine seedlings grown in open-top chambers in the early morning. Needles treated with 100 microM N(III) tended to have a greater maximum CO2 assimilation rate (Amax), a greater stomatal conductance (g(s)) and a greater needle nitrogen content (Nneedle), suggesting that N(III) mist acts as a fertilizer rather than as a phytotoxin. On the other hand, needles treated with 100 microM HOOH + Fe + oxalate solution showed the smallest Amax, g(s), and Nneedle, suggesting that the combination of HOOH + Fe + oxalate caused a decrease in needle productivity. The effects of HOOH + Fe + oxalate mist on pine needles were very similar to the symptoms of declining trees at Mt. Gokurakuji.
日本赤松（Pinus densiflora Sieb. et Zucc.）针叶表面的污染露水中会产生羟基自由基（OH）。这种自由基是一种强效氧化剂，被认为是日本西部极乐寺山面向城市一侧树木衰退的生态生理紊乱的一个原因。模拟露水的产生OH的N(III)（HNO2和NO2-）以及HOOH + Fe + 草酸盐溶液（50和100微摩尔，pH 5.1 - 5.4）的雾气在清晨被施加到开放式气室中生长的松树幼苗的叶子上。用100微摩尔N(III)处理的针叶往往具有更高的最大二氧化碳同化率（Amax）、更大的气孔导度（g(s)）和更高的针叶氮含量（Nneedle），这表明N(III)雾气起到了肥料而非植物毒素的作用。另一方面，用100微摩尔HOOH + Fe + 草酸盐溶液处理的针叶显示出最小的Amax、g(s)和Nneedle，这表明HOOH + Fe + 草酸盐的组合导致了针叶生产力的下降。HOOH + Fe + 草酸盐雾气对松针的影响与极乐寺山树木衰退的症状非常相似。
