Prolonged leaf senescence in Clusiamultiflora H.B.K.
Prolonged leaf senescence in Clusiamultiflora H.B.K.
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Clusiamultiflora H.B.K. 叶片衰老时间延长
DOI：
10.1007/pl00009681
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发表时间：
1997
期刊：
影响因子：
--
通讯作者：
E. Olivares
中科院分区：
文献类型：
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作者：
E. Olivares
摘要在热带云雾林中，采用人工处理方法，如在水中漂浮叶盘，或原位使附着于本植物上的叶片变暗，研究了多花Clusia （Clusia multiflora H.B.K.）叶片的老化和衰老。在这两种情况下，评估了一些随年龄变化的参数，如氮水平、叶绿素含量、多肉质和碳水化合物水平。与Heliocarpus americanus（5天）和Cecropia palmatisecta（20天）等物种相比，观察到长时间的衰老（近3个月），其特征是每面积叶重值较低，但与每面积叶重值较高且有机酸水平较高的物种相似，如Clusia minor和Fourcroya humboldtiana，其中酸可能作为C和能量的储备。野外采集的多花蒿叶片样品在黑暗条件下30天与未黑暗条件下的叶片在叶绿素、可滴定质子和碳水化合物方面没有差异，在黑暗条件下2个月的叶片进行光合作用。年龄对叶片的影响在叶片梯度中进行了评估，从先端开始在不同位置取样，年龄范围从15天到2年。对热带野生植物衰老的研究并不多见，但它对于理解叶片发育以及在季节不明显的气候条件下对内部而非环境调节的响应具有重要意义，如热带山地森林，在热带山地森林中，C. multiflora是早期演替植被的重要组成部分。
Abstract Leaf aging and senescence in Clusia multiflora H.B.K. was investigated by artificial treatments, such as floating leaf discs on water in darkness, or darkening leaves attached to the parent plant in situ in trees living in a tropical cloud forest. In both cases several parameters modified by age were evaluated such as nitrogen levels, chlorophyll content, succulence and carbohydrates levels. A prolonged senescence (nearly 3 months in floating leaf discs) was observed, contrasting with species such as Heliocarpus americanus (5 days) and Cecropia palmatisecta (20 days), characterized by low values of leaf weight per area, but similar to species with high leaf weight per area and with high levels of organic acids such as Clusia minor and Fourcroya humboldtiana, where acids may act as a reserve of C and energy. After 30 days in darkness C. multiflora leaf samples collected in the field did not show differences in comparison to non-darkened opposite leaves with respect to chlorophyll, titratable protons and carbohydrates, and leaves performed photosynthesis after 2 months in darkness. The effect of age in leaves was evaluated in a gradient of leaves, sampled at different positions from the apex and ranging in age from 15 days to 2 years old. The study of senescence in tropical wild plants is uncommon, but it is important knowledge for understanding foliar development, and response to internal rather than environmental regulation in climates where seasons are not strongly marked as is the case in the tropical mountain forest, where C. multiflora constitutes an important component in the early successional vegetation.