Influencial Factors Of The Storage And Germination Of Seed Of Intertidal Seagrass Halophila Beccarii

Halophila beccarii Aschers lives in intertidal of tropics,is one of the ten endangered seagrass species in the world and plays an important role in protecting the coastline,sea water purification,carbon fixation and keeping the balance of sea ecosystems.However,there are few research about Halophila beccarii.The influential factors,such as temperature,salinity,light and GA3 concentration,on storage and germination of Halophila beccarii seeds were studied in this research.It has important significance to conservation of Halophila beccarii.The influence on storage and germination were evaluated by death rate,germination rate,mean germination time and germination index of seed.Seed weight,water content,MDA content,POD activity and SOD activity were measure during the storage experiment and seed weight,water content,starch content and soluble sugar content were measure during the germination experiment to study the mechanism of action.Major results are as below:(1)Impacts of temperature,salinity on Halophila beccarii seed storagewere significant.Accumulative germination rate,germination index and accumulative death rate in 4? were significantly higher than those in 8?.High salinity will inhibit germination of H.beccarii seeds.Accumulative germination rate of seeds was significantly lower at salinity of 60‰ than other salinities(15‰,30‰ and 45‰).(2)Lower salinity could increase accumulative germination rate by mitigating stresses on H.beccarii seeds.Higher germination index and shorter germination period were achieved in such conditions.The concentration of MDA,the enzyme activity of POD and SOD,were significantly lower at lower salinity(1‰ and 5‰)than higher salinity(>5‰).(3)Halophila beccarii seeds germinated well in darkness.The accumulative germination rate and germination index were significantly higher under dark condition than under illumination.With the increasing of the illumination intensity,seed germination came worse,and the water content,seed dry weight and starch content changed significantly.(4)Inappropriate temperatures(both too low and too high)pose inhibiting effect on the seed germination of H.beccarii,and induce the significant increase of soluble sugar content.Highest accumulative germination rate and germination index of H.beccarii were observed under temperature of 25?.The treat of GA3 application(concentration of 200 mg·L-1),could enhance the seed germination of H.beccarii.All above results suggest that high salinity and 8? were the best storage condition of Halophila beccarii seed and temperature,salinity,light and GA3 concentration can signally affect the storage and germination of H.beccarii seed.