Shape-changes of the fast chlorophyll a fluorescence transient (OJIP) and antioxidative enzymes in high salt tolerant mangrove trees of Bruguiera gymnorrhiza

Abstract

True Mangrove trees of the costal habitats are now threaten of extinction because of climate change linked to global warming, sea level raise and fluctuating salinity. The key adaptation ability of the true tree mangroves having no salt secreting gland to survive in water logged high salt and anoxic condition seems to be shedding of lower leaves. The detailed mechanism of survival from high salt stress in this sea-shore mangroves is not known. We have examined the high salt stress effect in Bruguiera gymnorhiza a true tree mangrove in this study. Hydroponic culture of three months old nursery raised seedlings on B. gymnorizha were treated in 500 mmol NaCl (high salt) for 7 and 45 days. Both fast chlorophyll transients as well as the specific activity of key antioxidative enzymes were monitored to characterize the recovery potential of this mangrove from salt stress.