Increasing fluctuations of soil salinity affect seedling growth performances and physiology in three Neotropical mangrove species

• Published in: Plant and soil Vol. 380; no. 1-2; pp. 399 - 413
• Main Authors: Bompy, Felix, Lequeue, Gauthier, Imbert, Daniel, Dulormne, Maguy
• Format: Journal Article
• Language: English
• Published: Cham Springer-Verlag 01.07.2014; Springer; Springer International Publishing; Springer Nature B.V; Springer Verlag
• Subjects: Abiotic stress; acclimation; Acclimatization; Agronomy. Soil science and plant productions; Animal, plant and microbial ecology; Aquatic plants; Avicennia germinans; Biodiversity and Ecology; Biological and medical sciences; Biomass; Biomass production; Biomedical and Life Sciences; Caribbean; Climate change; Climate models; Dry season; Ecology; Environmental aspects; Environmental Sciences; Fluctuations; Forestry research; freshwater; Fundamental and applied biological sciences. Psychology; Gas exchange; General agronomy. Plant production; Global Changes; Growth; Growth (Plants); growth performance; Laguncularia racemosa; Leaf area; Leaves; Life Sciences; Mangrove plants; Mangroves; Mortality; Photosynthesis; Physiology; Plant ecology; Plant growth; Plant Physiology; Plant Sciences; Plant-soil relationships; Plants; prediction; Regular Article; Rhizophora mangle; Salinity; salt stress; Salt tolerance; seasonal variation; Seasonal variations; seedling growth; Seedlings; Sodium chloride; Soil salinity; Soil science; Soil Science & Conservation; Soil-plant relationships. Soil fertility; Soil-plant relationships. Soil fertility. Fertilization. Amendments; Soils, Salts in; Species composition; species diversity; Table salt; trees; tropics; Wetlands; Caribbean; France; ASW, Caribbean Sea; Salt stress; Hypersalinity; Acclimation; Leaf gas exchange; Growth rate; Growth; Plant juvenile growth stage; Tropical zone; Environmental factor; Rhizophora mangle; Evergreen plant; Laguncularia racemosa; Mangrove; Dicotyledones; Angiospermae; Hardwood forest tree; Plant marsh community; Developmental stage; Physiology; Neotropical Region; Species; Adaptation; Fluctuations; Avicennia germinans; Rhizophoraceae; Plant leaf; Salinity; Soils; Vegetation type; Verbenaceae; Vegetative apparatus; Vegetation; Spermatophyta; Gas exchange
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-014-2100-2

BACKGROUND: Micro-tidal wetlands are subject to strong seasonal variations of soil salinity that are likely to increase in amplitude according to climate model predictions for the Caribbean. Whereas the effects of constant salinity levels on the physiology of mangrove species have been widely tested, little is known about acclimation to fluctuations in salinity. AIMS AND METHODS: The aim of this experiment was to characterize the consequences of the rate of increase in salinity (slow versus fast) and salinity fluctuations over time versus constant salt level. Seedling mortality, growth, and leaf gas exchange of three mangrove species, Avicennia germinans, Laguncularia racemosa, and Rhizophora mangle were investigated in semicontrolled conditions at different salt levels (0, 685, 1025, and 1370 mM NaCl). RESULTS: Slow salinity increase up to 685 mM induced acclimation, improving the salt tolerance of A. germinans and L. racemosa, but had no effect on R. mangle. During fluctuations between 0 and 685 mM, A. germinans and R. mangle were not affected by a salinity drop to zero, whereas L. racemosa took advantage of the brief freshwater episode as shown by the durable improvement of photosynthesis and biomass production. CONCLUSIONS: This study provides new insights into physiological resistance and acclimation to salt stress. We show that seasonal variations of salinity may affect mangrove seedlings’ morphology and physiology as much as annual mean salinity. Moreover, more severe dry seasons due to climate change may impact tree stature and species composition in mangroves through higher mortality rates and physiological disturbance at the seedling stage.