ORIGINAL PAPER Protein and enzymes regulations towards salt tolerance of some Indian mangroves in relation to adaptation Nirjhar Dasgupta • Paramita Nandy • Chandan Sengupta • Sauren Das Received: 30 September 2010 / Revised: 17 January 2011 / Accepted: 21 July 2011 / Published online: 17 August 2011 Ó Springer-Verlag 2011 Abstract Elevated substrate salinity and anthropogenic impulse are the major threat to the mangrove ecosystem. In the Indian subcontinent, Sundarbans have the richest mangrove species diversity. Due to geomorphic charac- teristics and unplanned management, the elevated salinity prevails in the western part and that has direct impact on vegetation. Seven mangrove taxa were examined, of which four (Aegialitis rotundifolia, Heritiera fomes, Xylocarpus granatum, and X. mekongensis) were considered as degrading and three (Bruguiera gymnorrhiza, Excoecaria agallocha, and Phoenix paludosa) were considered as natural control. The targeted taxa were collected from five different islands and were selected on the basis of increasing salinity gradient. As salinity increased from site I to V (11.76–15.2 ppt), the amount of total leaf proteins decreased in all the targeted species and ranged between 5.67 and 25.23%. The percentage of protein depletion was less in Aegialitis, Heritiera, and Xylocarpus than the other three taxa in higher salinity that pointed out their less adaptability, as degradation of protein may be essential for efficient stress management. Two antioxidative (peroxidase and superoxide dismutase) and two hydrolyzing (acid phosphatase and esterase) enzymes showed a positive correlation with salinity. In four degrading taxa, the per- centage of enzyme increment was less than those of their natural control taxa. Salinity imposed increment of anti- oxidant enzymes facilitate ROS scavenging, which is an inevitable elevated byproduct during photo-inhibition. Lower amount and number of isoforms in higher salinity indicated towards less suitability of Aegialitis rotundifolia, Heritiera fomes, Xylocarpus granatum, and X. mekongensis in increased salinity level of western Sundarbans. Keywords Adaptation  Antioxidative enzymes  Hydrolyzing enzymes  Mangroves  Proteins  Salinity  Sundarbans Introduction Mangrove community consists of trees/shrubs having convergent adaptation to form a dense succession near the transitional zone of land and shoreline of the tropical and subtropical world. Different mangrove species may adopt distinct strategies to cope with the inhospitable criterion of high salinity due to their differential ability of salt man- agement in terms of anatomical, physiological, and molecular mechanisms (Das 1999; Nandy (Datta) et al. 2007, 2009; Dasgupta et al. 2010). Mangroves have been extensively studied for decades by the scientists (Chapman 1976; Saenger et al. 1983; Tomlinson 1986; Kathiresan and Bingham 2001; Lacerda et al. 2002). They usually perform a utility purpose of reformation of coastline both as pro- tective and productive dimension. It has been well estab- lished that they are considered as an ecologically essential component in protecting adjacent land by forming a front- line barrier against tidal waves and sea storm (Hogarth Communicated by U. Luettge. N. Dasgupta  S. Das (&) Agricultural and Ecological Research Unit, Indian Statistical Institute, 203, B.T.Road, Kolkata, 700 108, India e-mail: sauren@isical.ac.in P. Nandy Department of Botany, Barasat Government College, Kolkata 700 124, India C. Sengupta Department of Botany, Kalyani University, Kalyani 714 235, India 123 Trees (2012) 26:377–391 DOI 10.1007/s00468-011-0599-x