Vol.:(0123456789) 1 3 Acta Physiologiae Plantarum (2018) 40:160 https://doi.org/10.1007/s11738-018-2735-3 ORIGINAL ARTICLE The modulation of various physiochemical changes in Bruguiera cylindrica (L.) Blume afected by high concentrations of NaCl Sruthi Palliyath 1  · Jos T. Puthur 1 Received: 28 February 2018 / Revised: 25 July 2018 / Accepted: 28 July 2018 © Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Kraków 2018 Abstract Bruguiera cylindrica is a major mangrove species in the tropical mangrove ecosystems and it grows in a wide range of salini- ties without any special features for the excretion of excess salt. Therefore, the adaptation of this mangrove to salinity could be at the physiological and biochemical level. The 3-month-old healthy plantlets of B. cylindrica, raised from propagules were treated with 0 mM, 400 mM, 500 mM and 600 mM NaCl for 20 days under hydroponic culture conditions provided with full strength Hoagland medium. The modulation of various physiochemical changes in B. cylindrica, such as chloro- phyll a fuorescence, total chlorophyll content, dry weight, fresh weight and water content, Na + accumulation, oxidation and antioxidation (enzymatic and non-enzymatic) features were studied. Total chlorophyll content showed very minute decrease at 500 mM and 600 mM NaCl treatment for 20 days and the water content percentage was decreased both in leaf and root tissues with increasing concentration. A signifcant increase of Na + content of plants from 84.505 mM/plant dry weight in the absence of NaCl to 543.38 mM/plant dry weight in plants treated with 600 mM NaCl was recorded. The malondialdehyde and the metabolites content associated with stress tolerance (amino acid, total phenols and proline) showed an increasing pattern with increasing NaCl concentration as compared to the control in both leaf and root tissues but the increase recorded in plantlets subjected to 500 mM was much less, indicating the tolerance potential of this species towards 500 mM NaCl. The signifcant decrease of sugar content was found only in 600 mM NaCl on 20 days of treatment, showing that the process of sugar synthesis was negatively afected but the same process remains less afected at 500 mM NaCl. A slight reduction in ascorbate and glutathione content and very less increase in carotenoid content were observed at 500 mM and 600 mM NaCl stress. Antioxidant enzymes (APX, GPX, SOD and CAT) showed an enhanced activity in all the treatments and the increased activity was more signifcant in 600 mM treated plants. The result establishes that B. cylindrica tolerates high NaCl concentration, to the extent of 500 mM NaCl without any major inhibition on photosynthesis and metabolite accumulation. Understanding the modulation of various physiological and biochemical changes of B. cylindrica at high levels of NaCl will help us to know the physiochemical basis of tolerance strategy of this species towards high NaCl. Keywords Bruguiera cylindrica · Mangroves · Metabolic regulation · Chlorophyll a fuorescence · NaCl stress Introduction Intertidal forest areas are mainly inhabited by mangrove plants (Tomlinson 1986). These mangrove plants include woody trees and shrubs and they are the connecting line between the ocean and land mass of the tropical coastlines (Saenger 2002; Spalding 2010; Parida and Jha 2010). At the ecosystem level, mangrove forests have signifcant poten- tial in terms of its various uses and economic value (Bar- bier et al. 2011). Mangroves are always of great interest to biologist due to its high productivity, diversity and at the same time it has got several social and economic importance (Salem and Mercer 2012). Mangrove forests occupy an inter-tidal habitat, where sediment accumulation along with subsurface processes results in the elevation of sediments (Gilman et al. 2008). The tidal inundation from bay water infuences the sedi- ment salinities of these regions (Schile et al. 2014). With Communicated by R. Aroca. * Jos T. Puthur jtputhur@yahoo.com 1 Plant Physiology and Biochemistry Division, Department of Botany, University of Calicut, C.U. Campus P.O., Malappuram, Kerala 673635, India