Desiccation tolerance of five tropical seedlings in Panama. Relationship to a field assessment of drought performance

• Published in: Plant physiology (Bethesda) 2003-07, Vol.132 (3), p.1439-1447
• Main Authors: Tyree, M.T, Engelbrecht, B.M.J, Vargas, G, Kursar, T.A
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Calophyllum; Calophyllum longifolim; Desiccation; desiccation (plant physiology); Dipteryx oleifera; Disasters; Drought; Drought resistance; drought tolerance; Dry seasons; field experimentation; Fundamental and applied biological sciences. Psychology; Hydraulics; leaf water potential; Leaves; Licanai platypus; Licania; Magnoliopsida - metabolism; Ouratea lucens; Panama; Plant physiology and development; plant response; Plant roots; Plant Roots - metabolism; Plants; Seasons; Seedlings; Seedlings - metabolism; Species Specificity; Tropical Climate; Tropical forests; Tropical rain forests; Virola surinamensis; Water - metabolism; Water and solutes. Absorption, translocation and permeability; water stress; Whole Plant and Ecophysiology
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.102.018937

Studies of the desiccation tolerance of the seedlings of five tropical trees were made on potted plants growing in a greenhouse. Pots were watered to field capacity and then dehydrated for 3 to 9 weeks to reach various visual wilting stages, from slightly wilted to dead. Saturated root hydraulic conductance was measured with a high-pressure flowmeter, and whole-stem hydraulic conductance was measured by a vacuum chamber method. Leaf punches (5.6-mm diameter) were harvested for measurement of leaf water potential by a thermocouple psychrometer method and for measurement of fresh and dry weight. In a parallel study, the same five species were studied in a field experiment in the understory of a tropical forest, where these species frequently germinate. Control seedlings were maintained in irrigated plots during a dry season, and experimental plants were grown in similar plots with rain exclusion shelters. Every 2 to 4 weeks, the seedlings were scored for wilt state and survivorship. After a 22-week drought, the dry plots were irrigated for several weeks to verify visual symptoms of death. The field trials were used to rank drought performance of species, and the greenhouse desiccation studies were used to determine the conditions of moribund plants. Our conclusion is that the desiccation tolerance of moribund plants correlated with field assessment of drought-performance for the five species (r2 > 0.94).