Partitioning of water resources among plants of a lowland tropical forest
Partitioning of water resources among plants of a lowland tropical forest
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DOI：
10.1007/bf00317284
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发表时间：
1995-02
期刊：
影响因子：
2.7
通讯作者：
Paula C. Jackson;J. Cavelier;Guillermo Goldstein;F. Meinzer;N. Holbrook
中科院分区：
文献类型：
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作者：
Paula C. Jackson;J. Cavelier;Guillermo Goldstein;F. Meinzer;N. Holbrook
通过比较1992年旱季期间不同深度的木质部液和土壤水中氘、D和氢、H（稳定氢同位素组成δD）的相对丰度，对巴拿马Barro Colorado岛半常绿低地热带森林几种植物利用的水源水进行了评价。通过比较木质部水分δD值与叶片物候的关系，用压力室测定叶片水分状态，用茎热平衡法测定汁液质量流量的水分利用率，研究了水源水的生态相关性。土壤水分δD值在30 cm处急剧下降，而后随深度增加保持相对稳定。0 ~ 30 cm平均δD值为13‰，30 ~ 100 cm平均δD值为36.7‰。土壤水分δD值与土壤含水量和土壤水势呈负相关。木质部水分的同步分析揭示了该热带森林物种间水资源的高度分配。落叶乔木木质部水分δD（平均=-25.3±1.4‰）高于常绿乔木木质部水分δD（平均=-36.3±3.5‰），说明常绿乔木比落叶乔木在更深层获得了更丰富的土壤水分。在常绿耐遮荫、高光的灌木和小树中，木质部水分δD与蒸腾速率和叶片水势呈负相关，表明利用更深层、更丰富的水资源的物种具有更高的水分利用率和更有利的叶片水分状况。
Source water used by plants of several species in a semi-evergreen lowland tropical forest on Barro Colorado Island, Panama, was assessed by comparing the relative abundance of deuterium, D, versus hydrogen, H (stable hydrogen isotope composition, δD) in xylem sap and in soil water at different depths, during the dry season of 1992. Ecological correlates of source water were examined by comparing xylem water δD values with leaf phenology, leaf water status determined with a pressure chamber, and rates of water use determined as mass flow of sap using the stem heat balance method. Soil water δD values decreased sharply to 30 cm, then remained relatively constant with increasing depth. Average δD values were-13‰, for 0–30 cm depth and-36.7‰ for 30–100 cm depth. Soil water δD values were negatively associated with soil water content and soil water potential. Concurrent analyses of xylem water revealed a high degree of partitioning of water resources among species of this tropical forest. Xylem water δD of deciduous trees (average=-25.3±1.4‰) was higher than that of evergreen trees (average=-36.3±3.5‰), indicating that evergreen species had access to the more abundant soil water at greater depth than deciduous species. In evergreen shade-tolerant and high-light requiring shrubs and small trees, δD of xylem water was negatively correlated with transpiration rate and leaf water potential indicating that species using deeper, more abundant water resources had both higher rates of water use and more favorable leaf water status.