Environmental control of flowering periodicity in Costa Rican and Mexican tropical dry forests
Environmental control of flowering periodicity in Costa Rican and Mexican tropical dry forests
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DOI：
10.1111/j.1466-822x.2004.00111.x
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发表时间：
2004-09-01
影响因子：
6.4
通讯作者：
Porter-Bolland, L
中科院分区：
文献类型：
--
作者：
Borchert, R;Meyer, SA;Porter-Bolland, L
目的我们分析了四种热带干旱森林（TDF）开花周期性大幅度变化的近因，并询问气候周期性或生物相互作用是否是开花周期性的最终原因。（哥斯达黎加）、尤卡坦、哈利斯科和索诺拉（墨西哥）的特点是旱季长达5-7个月，位于沿着纬度梯度增加（10- 30度N）。方法在群落水平上观察到开花周期的差异，将单个树种分配到“开花类型”，即由环境开花线索和植物物候学的相似组合决定的具有特征开花期的物种群。在旱季和雨季开花的类型，分别表明四种森林之间的季节性干旱的严重程度有很大的差异。在哈利斯科干旱的高地森林，无叶树木的开花在严重的季节性干旱期间仍然受到抑制，并由雨季的第一场雨引发。在其他森林中，落叶、异常降雨或日照时间的增加导致许多落叶物种在旱季的不同时间开花，早在夏季降雨之前。落叶物种的比例在夏季降雨和开花时，无叶在旱季是最大的索诺兰TDF.Main结论在许多广泛的物种开花周期的表型可塑性大。春季开花的无叶枝和随后的夏季冲洗的明显的时间间隔代表了一个独特的适应树木发展的气候与相对较短的雨季和漫长的旱季。降雨量和土壤水分供应的季节性变化显然不仅构成了开花周期性的近因，而且也是开花周期性的最终原因，开花周期性不太可能是生物适应压力的反应。
Aim We analyse the proximate causes of the large variation in flowering periodicity among four tropical dry forests (TDF) and ask whether climatic periodicity or biotic interactions are the ultimate causes of flowering periodicity.Location The four TDFs in Guanacaste (Costa Rica), Yucatan, Jalisco and Sonora (Mexico) are characterized by a 5-7 month long dry season and are located along a gradient of increasing latitude (10-30degreesN).Methods To dissect the differences in flowering periodicity observed at the community level, individual tree species were assigned to 'flowering types', i.e. groups of species with characteristic flowering periods determined by similar combinations of environmental flowering cues and vegetative phenology.Results Large variation in the fraction of species and flowering types blooming during the dry and wet season, respectively, indicates large differences in the severity of seasonal drought among the four forests. In the dry upland forests of Jalisco, flowering of leafless trees remains suppressed during severe seasonal drought and is triggered by the first rains of the wet season. In the other forests, leaf shedding, exceptional rainfall or increasing daylength cause flowering of many deciduous species at various times during the dry season, well before the summer rains. The fraction of deciduous species leafing out during the summer rains and flowering when leafless during the dry season is largest in the Sonoran TDF.Main conclusions In many wide-ranging species the phenotypic plasticity of flowering periodicity is large. The distinct temporal separation of spring flowering on leafless shoots and subsequent summer flushing represents a unique adaptation of tree development to climates with a relatively short rainy season and a long dry season. Seasonal variation in rainfall and soil water availability apparently constitutes not only the proximate, but also the ultimate cause of flowering periodicity, which is unlikely to have evolved in response to biotic adaptive pressures.