Growth of Japanese and hybrid larch seedlings grown under free-air O-3 fumigation-an initial assessment of the effects of adequate and excessive nitrogen
Growth of Japanese and hybrid larch seedlings grown under free-air O-3 fumigation-an initial assessment of the effects of adequate and excessive nitrogen
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DOI：
10.2480/agrmet.d-14-00029
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发表时间：
2015-09
影响因子：
1.3
通讯作者：
Kam Dong-Gyu;Cong Shi;Makoto Watanabe;K. Kita;F. Satoh;T. Koike
中科院分区：
文献类型：
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作者：
Kam Dong-Gyu;Cong Shi;Makoto Watanabe;K. Kita;F. Satoh;T. Koike
东亚森林中地表臭氧（O3）和氮（N）沉积量正在迅速增加。日本落叶松（JL）已从日本中部移植到北部地区。由于JL患有茎枯病和田鼠吃草，因此开发了杂交落叶松（F1）来克服这些弱点。为了可持续利用这些落叶松，我们应该了解日本北部落叶松对 O3 (eO3) 升高和过量氮沉降的生长反应。由于土壤缺乏养分，将 2 年生 JL 和 F1 幼苗盆栽于风化良好的未成熟火山灰土中，基施含 47 kgN 干草的平衡肥料。为了模拟 eO3，幼苗在自由空气 O3 熏蒸系统（白天 60 nmol 莫林）中生长。此外，为了模拟酸雨，向植物施用了 NH4NO3（总共 50 kgN 干草）。与氮负荷无关，JL 和 F1 中 eO3 下的针叶干质量均小于环境 O3 下的针叶凋落物干质量。在 eO3 条件下，两种落叶松针叶脱落前氮的重新移位均较低。因此，eO3 时每针地上生物量（即生产效率）更高。
Ground-surface ozone (O3) and nitrogen (N) deposition in forests are increasing rapidly in East Asia. The Japanese larch (JL) has been transplanted from central Japan to northern areas. Because the JL suffers from shoot blight disease and grazing by voles, the hybrid larch (F1) was developed to overcome these weak points. For sustainable use of these larches, we should know the growth responses of larches to elevated O3 (eO3) and excessive N deposition in northern Japan. Two-year-old JL and F1 seedlings were potted in well-weathered immature volcanic ash soil with basal dressing of balanced fertilizer containing 47 kgN hayr-, due to a lack of nutrients in the soil. To simulate eO3, seedlings were grown in a free-air O3 fumigation system (60 nmol molin daytime). Also, to simulate acid rain, NH4NO3 (50 kgN hayrin total) was applied to the plants. Independent of the N loading, the dry mass of needle litter in both JL and F1 was less at eO3 than at ambient O3. Re-translocation of N before the needle shedding of both larches was lower under eO3. As a result, the aboveground biomass per needle (i.e. productive efficiency) was higher at eO3.