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Leaf water storage increases with salinity and aridity in the mangrove Avicennia marina : integration of leaf structure, osmotic adjustment and access to multiple water sources
Author(s) -
Nguyen Hoa T.,
Meir Patrick,
Sack Lawren,
Evans John R.,
Oliveira Rafael S.,
Ball Marilyn C.
Publication year - 2017
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.12962
Subject(s) - avicennia marina , turgor pressure , salinity , arid , biology , osmoregulation , botany , population , water content , agronomy , horticulture , mangrove , ecology , demography , geotechnical engineering , sociology , engineering
Leaf structure and water relations were studied in a temperate population of Avicennia marina subsp. australasica along a natural salinity gradient [28 to 49 parts per thousand (ppt)] and compared with two subspecies grown naturally in similar soil salinities to those of subsp. australasica but under different climates: subsp. eucalyptifolia (salinity 30 ppt, wet tropics) and subsp. marina (salinity 46 ppt, arid tropics). Leaf thickness, leaf dry mass per area and water content increased with salinity and aridity. Turgor loss point declined with increase in soil salinity, driven mainly by differences in osmotic potential at full turgor. Nevertheless, a high modulus of elasticity ( ε ) contributed to maintenance of high cell hydration at turgor loss point. Despite similarity among leaves in leaf water storage capacitance, total leaf water storage increased with increasing salinity and aridity. The time that stored water alone could sustain an evaporation rate of 1 mmol m −2 s −1 ranged from 77 to 126 min from subspecies eucalyptifolia to ssp. marina , respectively. Achieving full leaf hydration or turgor would require water from sources other than the roots, emphasizing the importance of multiple water sources to growth and survival of Avicennia marina across gradients in salinity and aridity.