Increasing day-length induces spring flushing of tropical dry forest trees in the absence of rain
Increasing day-length induces spring flushing of tropical dry forest trees in the absence of rain
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DOI：
10.1007/s00468-002-0185-3
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发表时间：
2002-09
期刊：
影响因子：
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通讯作者：
G. Rivera;S. Elliott;L. Caldas;Guillermo Nicolossi;V. Coradin;R. Borchert
中科院分区：
文献类型：
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作者：
G. Rivera;S. Elliott;L. Caldas;Guillermo Nicolossi;V. Coradin;R. Borchert
在许多50种同种乔木中，在旱季末期、春分前后、阿根廷、哥斯达黎加、爪哇和泰国的半落叶热带森林以及巴西中部的热带稀树草原中，观察到高度同步的芽折现象，年际变化很小。北半球和南半球之间的萌发时间相差6个月，亚热带地区的萌芽开始时间比低纬度地区早了大约1个月。这些观察表明，光周期每增加30分钟或更少，就会导致“春潮”，即春分前后和雨季第一场雨前几周的同步萌芽中断。春潮在干旱季节为4-6个月、年降雨量为800-1500毫米的半落叶森林中很常见，但在干旱季节较短或年降雨量较少的新热带森林中很少见。在生长季节相对较短的热带森林中，在湿润的生长季前不久建立新的树叶可能会优化光合作用的增益。
In many conspecific trees of >50 species highly synchronous bud break with low inter-annual variation was observed during the late dry season, around the spring equinox, in semideciduous tropical forests of Argentina, Costa Rica, Java and Thailand and in tropical savannas of Central Brazil. Bud break was 6 months out of phase between the northern and southern hemispheres and started about 1 month earlier in the subtropics than at lower latitudes. These observations indicate that "spring flushing", i.e., synchronous bud break around the spring equinox and weeks before the first rains of the wet season, is induced by an increase in photoperiod of 30 min or less. Spring flushing is common in semideciduous forests characterized by a 4–6 month dry season and annual rainfall of 800–1,500 mm, but rare in neotropical forests with a shorter dry season or lower annual precipitation. Establishment of new foliage shortly before the wet growing season is likely to optimize photosynthetic gain in tropical forests with a relatively short growing season.