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Trees (2010) 24:199217DOI 10.1007/s00468-010-0417-x
REVIEW
Salt tolerance mechanisms in mangroves: a review
Asish Kumar Parida Bhavanath Jha
Received: 15 April 2009 / Revised: 19 December 2009 / Accepted: 20 January 2010 / Published online: 11 February 2010 Springer-Verlag 2010
Abstract Mangroves are woody plants which form the dominant vegetation in tidal, saline wetlands along tropical and subtropical coasts. The current knowledge concerning the most striking feature of mangroves i.e., their unique ability to tolerate high salinity is summarized in the present review. In this review, we shall discuss recent studies that have focused on morphological, anatomical, physiological, biochemical, molecular and genetic attributes associated with the response to salinity, some of which presumably function to mediate salt tolerance in the mangroves. Here we shall also review the major advances recently made at both the genetic and the genomic levels in mangroves. Salinity tolerance in mangroves depends on a range of adaptations, including ion compartmentation, osmoregulation, selective transport and uptake of ions, maintenance of a balance between the supply of ions to the shoot, and capacity to accommodate the salt inux. The tolerance of mangroves to a high saline environment is also tightly linked to the regulation of gene expression. By integrating the information from mangroves and performing comparisons among species of mangroves and non-mangroves, we could give a general picture of salt tolerance mechanisms of mangroves, thus providing a new avenue for development of salt tolerance in crop plants through effective breeding strategies and genetic engineering techniques.
Keywords Antioxidant Compatible solutes
Mangrove Na?/H? antiporter Salt tolerance
Salt secretor Salt exclusion Propagules Viviparous
Introduction
True mangroves and mangrove associates
Mangroves are constituent plants of tropical intertidal forest community. They include woody trees and shrubs, which ourish in the zone between land and sea along the tropical coastline of the globe. They fall into two groups according to their habitats in nature: true mangroves and mangrove associates. True mangroves occur only in man-grove habitat and their existence is rare elsewhere such as Rhizophora, Kandelia, Ceriops, Bruguiera, Avicennia, Xylocarpus, Aegiceras, Sonneratia, Laguncularia, Lumnitzera, Nypha etc. Mangrove associates are non-exclusive mangrove species occurring in the landward margin of mangal and often non-mangal habitats such as rainforest, salt marsh or lowland freshwater swamps (e.g. Excoecaria, Camptostemon, Pemphis, Osbornia, Pelliciera, Aegialitis, Acrostichum,...