Impacts of Climate Change Induced Salinity Intrusion on Physiological Parameters of Some Aquatic Hydrophytes

Abstract

Changing temperature, precipitation regimes, sea-level rise- all of these are associated with the global phenomenon; climate change. An inevitable consequence of this global phenomenon is salinity intrusion which is the gradual movement of salinity into groundwater as well as surface water. This salinity intrusion can have detrimental impacts on the hydrophytes or the plants living in these water sources. This experiment was conducted to see the varying impacts on the physiological traits of Water Hyacinth (Eichhornia crassipes), Helencha (Enhydra Fluctuans) , Taro (Colocasia esculenta) against different salinity concentrations (0 ppt , 10 ppt, 20 ppt, 30 ppt) after 48 hours due to increasing salinity as well as their physical adaptations. The physiological parameters that were measured in this experiment were Biomass, Height , Stomatal density, Transpiration rate, Total Chlorophyll Content and Relative water content. A prominent reduction in biomass and height was noticed with increasing salinity. For stomatal density it was established that the number of stomata per millimeters square decreased with the increase in salinity concentration. Result for transpiration rate was also in compliance with the result of stomatal density. As Colocasia esculenta was observed to be salt tolerant to some extent and had a stomatal density of 6 mm-2 at 30 ppt it had the capacity to transpire after 48 hours whereas the rest of the two plants did not have any open stomata at 30 ppt. Hence there was no transpiration in Eichhornia crassipes and Enhydra Fluctuans after 48 hours. Chlorophyll content was also found to be decreasing in Eichhornia crassipes and Enhydra Fluctuans but increasing in Colocasia esculenta with the increasing salinity concentration. RWC decreased substantially for all the hydrophytes with increasing salinity concentration after 48 hours. All the plants upon prolonged exposure did not survive and the physiological alteration observed and measured after 48 hours justified these conclusions.