The Differential Responses Of Aegiceras Corniculatum And Kandelia Obovata Based On Electrophysioloical And Growth Parameters Under Different Environmental Conditions

Mangrove species grow in the intertidal areas of tropical and subtropical zones of coastlines and perform an important role in the coastal area such as protect from the natural disaster,tidal flood,seawater-intrusion,and salinity.Mangrove species provide basic needs for life such as food,raw material,timber,tourisms,and herbal medicines etc.Mangroves are considered salt tolerance species because they can survive in stressful conditions such as low oxygen,high salinity,and low humidity.During the stress conditions,mangroves developed various mechanisms which help to resistant salt stress.Therefore,the differential responses of two different mangroves species Aegiceras corniculatum and Kandelia obovate in diverse salt levels were investigated in this study.Furthermore,electrophysiological parameters perform an important role to fast and online diagnose plant water status,since the variations of plant cell volume and cell sap concentration and compositions will timely change.Due to variations in cell volume,cell sap content,and composition,electrophysiological parameters have gradually been used to diagnose the water status of plants.This approach,however,is unstable and difficult to manipulate.Due to needle-induced injuries,differences in surroundings,users,and other factors,the electrical signals obtained frequently lack representativeness,repeatability,and comparability.Various changes in plant physiological processes such as photosynthesis,stomatal conductance,respiration,transpiration,substance flow,energy metabolism and plant growth,directly or indirectly linked with electrical signal.Based on electrophysiological data and growth metrics,a novel technique to restore mangrove species is suggested in the current study.Additionally,tools from the Geographical Information System（GIS）and remote sensing（RS）are used to track soil salinity and evaluate the current state of different mangrove species.These methods provide real-time data,which is extremely helpful for managing mangrove species dynamically and permits the development of mangrove restoration plans in accordance with local conditions.Electrophysiology allows us to explore the transport of ions and other physiological processes that contribute to their salt tolerance capacities.Assessing the growth parameters under different environmental conditions helps us understand their overall performance and capability.This knowledge can contribute to our understanding of how mangroves respond to environmental stressors,providing valuable information for conservation and ecosystem management.The findings of this research can have practical applications in mangrove restoration,management,and conservation efforts.Understanding the specific responses of A.corniculatum and K.obovata to different environmental conditions can guide the selection of appropriate species for restoration projects based on the targeted environmental conditions.In the first experiment compared the physiological capacitance（CP）and photosynthesis parameters to understand which can better represent water status in mangroves leaves.The experiment was performed in green house and used six different treatments salt stress phase:(CK,0m M Na Cl;Low,100m M Na Cl;Medium,200m M Na Cl;High,400m M Na Cl.Re-watering phase:（M-L,200-100m M Na Cl;H-M,400-200m M Na Cl）for the determination of electrophysiological,photosynthesis and growth parameters.In re-watering phase only change two treatments first one medium-low and other one high-medium salt level.The results indicated that the CP of A.corniculatum was significantly decreased with increasing salt concentrations in the salt stress phase,while the CP values of K.candel species at low treatment was higher as compared to control,and the CP values were slightly decreased at the medium and high treatments.In re-watering phase,when the salt concentration decreased,K.candel species showed a good response especially at high–moderate（H-M）treatment as compared to A.corniculatum.According to the growth rate,A.corniculatum decreased by 95.5%and K.candel 67.9%,respectively,in high–high（H-H）treatment compared to control.These findings indicate that the concentration of solute in vacuole is an important factor controlling photosynthesis and growth parameters,and CP can better represent salt concentration in the plant leaves.In the 2^nd experiment,the inherent electrical parameters were monitored,which electrical parameter could better reflect in different salt levels and check the impact of re-watering and SNP application.According to bioenergetics,the theoretical relationship between clamping force（CF）and leaf resistance（R）,capacitive reactance（XC）,inductive reactance（XL）,impedance（Z）and capacitance（C）were exposed for mangroves species.The intrinsic resistance（IR）,capacitive reactance（IXC）,inductive reactance（IXL）,impedance（IZ）,and capacitance（IC）in plant leaves were successfully monitored,the intracellular water-holding capacity（IWHC）,water-use efficiency（IWUE）,water-holding time（IWHT）of mangrove species and the salt flux per unit area（USF）,salt transfer rate（STR）and salt transport capacity（STC）based on mechanical equations of IR,IXC,IXL,IZ and IC were defined to intracellular water metabolism and salt transport characteristics.Results showed that inherent capacitance（IC）and effective thickness（ET）could better represent A.corniculatum species at different salt level,while intracellular water-holding capacity（IWHC）,and salt transport capacity（STR）showed significant results under salt stress condition.Moreover,intrinsic resistance（IR）and intrinsic impedance（IZ）were obviously affected under different salt level of Kandelia obovata（K.obovata）species.The Sodium nitroprusside（SNP）application with Na Cl showed positive results on three different capacities（salt outflow,dilution and ultrafiltration capacity）of A.corniculatum in all salt levels,they were greatly improved by SNP especially at low salt level.Furthermore,the re-watering technique did not improve or significantly alter the responses of A.corniculatum,whereas K.obovata exhibited better results under high salt levels when re-watering was implemented.The electrophysiological parameters of mangroves,which are based on bioenergetics,provide valuable insights into intracellular water metabolism.Additionally,the information obtained from salt transport parameters effectively demonstrates variations in membrane proteins,offering a quick and reliable method for determining the intracellular water status of metabolism and salt transport characteristics.These electrophysiological parameters play a crucial role in understanding the physiological responses of mangroves to environmental conditions.The 3^rd experiment depended on dynamic management of mangroves specie based on electrophysiological information,remote sensing（RS）and Geographical information system（GIS）techniques.This study aimed to understand desalination effect and nutrients plunder capacity of mangrove species,and investigate the current condition of Quanzhou Bay wetland which has been suffering environmental concerns.Results of study indicated that K.obovata species had higher nutrients plunder（active transport）capacity and salt resistant capacity as compared to A.corniculatum.Therefore,K.obovata can survive in higher stress conditions.Additionally,over the period from 2008 to 2021,there was a significant increase of 21%in the tidal flood plain area,accompanied by a 7%decrease in mangrove/vegetation.Based on the results obtained,it was determined that K.obovata species had a greater capacity for nutrient transport.Consequently,it is recommended to prioritize the replanting of K.obovata species in the lower and middle parts of Quanzhou Bay.This choice takes into consideration the species’ability to efficiently extract nutrients from the environment,which can contribute to the restoration and conservation of the affected areas.In this thesis,rapid and real-time acquisition information of mangrove plants response in different salinity levels was obtained based on electrophysiological parameters.Salt transports characteristics and nutrients plunder capacity also determined how mangrove upstand in stress condition with their unique mechanisms.In addition,GIS&RS data facilitated policy maker and manager to manage the mangrove species according to local condition of coastal areas.