The Studies Of Factors Influencing The Germination Of The Seed Of Zostera Marina L.

Sea grass bed as a representative marine ecosystem with high productivity, had animportant influence on the marine living resources and the biodiversity conservation.But the phenomenon that seagrass bed was degraded worldwide, mainly caused byhuman activities, was received wide attention and studied. Although restoring theseagrass bed with seed was valued and developed, the knowledge of germinationneeded to perfect and the germination rate was very low. This paper took Zosteramarina L. as a research object to research the influence of factors, like salinity,temperature, light, et al., for improving the germination percentage and making seedgermination time short and providing the basises for optimizing and improving thetechnique that restored the source of Zostera marina L. with seeds. In order to solveenvironmental plasticity of seagrass, we made a combine research of genentic andmorphological studies to identify the species of seagrass used in the research.The main results are as follows:(1)The matured Zostera marina’s seed, which was identified by the morphologicalstudies and gene sequences alignments and phylogentic trees analyses, had an oval ora long rounded shape and a micropyle in the end without cotyledon; it had two seedcoats, the outer was hard with dark brown or black color radial ridges, which rangefrom14to22, while the inner was a thin layer seemed smooth.(2)The influence of salinity on the germination of Zostera marina’s seed was themost obvious in this research. The germination percentage and germinate time in lowsalinity condition (such as0and5) was significantly higher and shorter than in highsalinity condition (such as20and30). So, the conditions of high salinity (ranged from30to34) were suitable for preserving seed (which could keeping alive more than6months), while the low salinity conditions were better for germinating. (3) Temperature ranged from10℃to25℃didn’t have significant influence on thegermination of Zostera marina’s seed, but the germination rate and percentage in20℃and25℃were higher than15℃, and10℃could improve the germinationpercentage, but had no effect on the germination rate. The pretreatments of4℃and30℃of24h would improve germination rate and percentage of the seed that culturedin15℃; but the germination would be inhibited after the seed had gotten a long-timepretreatment in30℃, like after more than5days, while there were no differences ofthe germination percentage and rate between the pretreatments in4℃and15℃. Theseed preserved in seawater with temperature naturally slow down (from12℃to5.3℃)had significantly higher germination percentage and shorter germination time.(4) The germination rate and percentage of seed were higher in the condition with nolight than light, but the differences were not significant.(5) Although the artificial managements of Zostera marina’s seed coat wouldimprove the germination rate and percentage, such as cut a line in seed or remove theseed coat, the effects of germination weren’t significant; the juice of the seed coatscould restraint the germinate.