WATER POTENTIAL GRADIENTS FOR GAPS AND SLOPES IN A PANAMANIAN TROPICAL MOIST FORESTS DRY SEASON
WATER POTENTIAL GRADIENTS FOR GAPS AND SLOPES IN A PANAMANIAN TROPICAL MOIST FORESTS DRY SEASON
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DOI：
10.1017/s0266467400002674
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发表时间：
1988-05-01
影响因子：
1.4
通讯作者：
SMITH, AP
中科院分区：
文献类型：
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作者：
BECKER, P;RABENOLD, PE;SMITH, AP
旱季期间，每周在巴拿马巴罗科罗拉多群岛的热带潮湿森林中使用干湿球湿度计在20厘米深的地方测量土壤水势。无论是大林隙还是小林隙，土壤水分从林隙中心到林隙边缘再到相邻林下都存在持续的下降梯度。在南北向和东西向的横断面上，高地表面的土壤比中度斜坡上的土壤更干燥（水势更负）。这一趋势反映在黎明前，总水势浅根Psychotria horizonalis和深根Trichilia tuberculata测量在下层在旱季的最后两个月。在完全水化和零膨压下，样带上最潮湿的地点的水平木具有更高的渗透势，表明抗旱性低于最干燥的地点的同种植物。
Soil water potentials were measured weekly by psychrometers at 20 cm depth during the dry season in a tropical moist forest on Barro Colorado Islands, Panama. There was a persistent gradient of decreasing soil moisture from gap centre to gap edge to adjacent understorey at both a large and a small gap. On both a north-south and an east-west transect, the soil was drier (water potentials were more negative) on a upland surface than on moderate slopes. This trend was reflected in the predawn, total water potentials of shallow-rooted Psychotria horizonalis and deep-rooted Trichilia tuberculata measured in the understorey during the last two months of the dry season. P. horizontalis from the wettest sites on the transects had higher osmotic potentials at fully hydration and at zero turgor, indicating less drought resistance than for conspecifics from the driest sites.