Studies On Tissue Cultivation And Physiological Response To Salt Stress Of Zostera Marina L.

Eelgrass （Zostera marina L.） is a kind of marine higher flowering plant withgreat ecological value and economical value. Due to the degradation of natureenvironment and disturbance of human activities, eelgrass faces a great lossworldwide. There are two challenges in the restoration of eelgrass bed: set upeffective artificial cultivation technique to gain lots of shoots for restoration inadvance of no damaging on nature population, get well known on the physiologicalmechanisms in eelgrass responding to salt stress in order to guide populationrestoration in the situation of high salinity in coastal areas. Thus, the paper studies ontissue cultivation and physiological response to salt stress of eelgrass, to providetechniques and theories for restoration of eelgrass bed. The results are as below:1. Sudies on tissue cultivation of eelgrass.Selecting the type of disinfectants and optimizing concentration and disinfectingtime. Use the kind of disinfectants, concentration and disinfecting time as parametersto do factorial analysis experiments, to study the effectiveness of differentdisinfectants in types, concentration and disinfecting time on eelgrass explant. Theresult shows the most effective method of disinfecting among experimental groups is8minutes disinfecting in0.1%HgCl₂.Selecting the type of auxiliary disinfectants and optimizing concentration anddisinfecting time. The result shows the most effective method of auxiliarilydisinfecting is1hour disinfecting in0.5%povidone iodine.Selecting the type of antibiotics and optimizing MIC （minimal inhibitoryconcentration）. To guarantee the regular growth in aseptic conditions, antibiotics areadded in culture medium for long-term inhibition. When antibiotics inhibit bacteria,they also have influences on explants, so experiments on selecting the kind ofantibiotics and MIC should be done. The result shows100μg/mL kanamycin and25μg/mL neomycin sulfate is optimal combination. Selecting parts for explant. Take the rate of contaminated explant as indicator,compare the part of stem tip and the part of stem. The result shows the rate of stem tippart is a half less than the rate of stem part, The stem tip part is better for explant.Inhibition of browning. By the study on activated carbon content, illuminationintensity and selecting part as explant, discuss the effective methods in inhibition ofbrowning. The result shows0.3%activated carbon, less illumination intensity andselecting stem tip part as explant are all effective methods to inhibit browning.Comprehensive the above results, the effective method on eelgrass tissuecultivation is:（1） selecting stem tip part as explant;（2） cleaning on explant surface,using dishwashing liquid to clean sediment and microalgae;（3） disinfecting explantwith the turns of15seconds in75%alcohol,1hour in0.5%povidone iodine,8minutes in0.1%HgCl2;（4） adding100μg/mL kanamycin and25μg/mL neomycinsulfate in culture medium;（5） inhibiting browning, adding0.3%activated carbon inculture medium and reducing illumination intensity.2. Studies on mechanism of physiological response to salt stress of eelgrass.In lab conditions, study on physiological response of eelgrass in different salinity.Take permeability of plasma membrane, proline content, chlorophyll content andMDA content as indicators, study on on physiological response of eelgrass in differentsalinities （0,10,20,30,40,50,60）. The results show,（1） High salinity leads to highpermeability of plasma membrane making intracellular material spreads to externalenvironment which can not maintain the normal physiological activity,（2） with theincrease of salinity, proline is accumulated in eelgrass in a large scale, which has antoxic action on eelgrass,（3） with the increase of salinity, the content of chlorophylldescends,（4） with the increase of salinity, the content of MDA rises.Comprehensive the above results,（1） the suitable salinity range for eelgrassliving is10-30,（2） the most suitable salinity for eelgrass living is about20,（3） whenthe salinity is more than40, eelgrass can not grow normally,（4） when the salinity ismore than60, the plasma membrane is seriously damaged and it has a highpermeability, the cells of eelgrass can not maintain the basic physiological activity.