Effect Of Salinity And Dimorphic Seeds On Plant Growth And Fecundity Of Salicornia Europaea

During the long-term evolution,the halophytes have evolued some special physiological and ecological mechanisms to face the harsh habitats.In this study,we studied Salicornia europaea,an annual true halophyte in Yuncheng Salt Lake area,Dagang area in Tianjin,and Fukang area in Xinjiang,and used the combination of indoor experiment and outdoor greenhouse cultivation.This method mainly explores:(1)The response of plant biomass,morphology,reproductive traits and seed traits produced by two different types of seeds to salt stress;(2)Under different salt concentrations Experiments were conducted on the seeds of the seeds produced by the dimorphic seeds of Salicornia europaea to investigate the effects of seed type,temperature and maternal effects on the germination of the offspring of the offspring;(3)The difference in response of germination of Salicornia europaea seeds to salt stress from Fukang of Xinjiang,Dagang of Tianjin,and Yancheng of Yuncheng districts.The main results are as follows:1.Salicornia europaea can produce two distinctly different types of seeds.(1)Height,the number of branches and the length of main root of plants from dimorphic seeds decreased with increasing salt concentrations,but were not significantly different at the same salt concentration.(2)Total biomass,above-ground biomass and under-ground biomass per plant from large seeds were highest at the concentration of 4.0,4.0 and 2.0%.However,these biomass indexes from small seeds were all highest at 2.0%.(3)With the increase of salt concentration,the number of large and small seeds of plants from dimorphic seeds decreased which was more drastic decrease was showed in small seeds,showing the rise of separation ratio,and increase of seed size.(4)With the increase of salt concentration,The reproductive allocation and root shoot ratio of both plants gradually decreased and reproductive allocations were maintained at 40-55%.(5)Germination rates of large and small seeds from both plants under high salinity were faster than those under low saling.2.The salt changes experienced by the from dimorphic plants seeds had a significant effect on the germination of their seeds,especially germination rate.The germination percentage of large seeds of Salicornia europaea reached nearly 100% under different temperatures from two sources.Under four temperature gradients,the germination percentage of small seeds under both sources was more than 60%,but germination percentage was the highest under 15/25°C,and the germination percentage was the lowest under 5/15°C.Germination percentage of small seeds from small seed plants were higher than those from large seed plants under the same temperature.With the increase of temperature,the average germination time of the heterotypic seeds from both sources gradually decreased,and the germination rate increased.The average germination time of the small seeds was higher than that of the big seeds under the same treatment conditions.Under the conditions of 15/25°C,after the plants were subjected to different salt treatments,the final germination of the small seeds from the big seeds was significantly lower than that of the small seeds from the small seed plants.The initial germination was higher and the germination time was earlier than that of seeds that had not been treated with salt under the same conditions.3.With the decrease of temperature and the increase of salt concentration,the germination percentage and germination potential of Salicornia europaea seed from three provenances decreased under three temperature gradients,and the germination time was prolonged.The salinity tolerance of the large seeds of Yuncheng Salt Lake and Fukang were very strong,and the higher germination percentage can still be achieved at a salinity concentration of 1.3 mol/L.However,the Salicornia europaea seeds in Salt Lake are more resistant than that in Xinjiang Fukang.salt.In darkness,with the increase of temperature and salt concentration,germination percentage of small seeds decreased,and large seeds were insensitive to light.Germination of small seeds required light irradiation,within a certain range of low temperatures.Low temperature counteracted the effects of darkness on the germination of small seeds.The germination rate and germination index were the highest for the two different types of seeds of Salicornia europaea in Yuncheng Salt Lake under the same salt treatment,and germination time was the shortest.The germination percentage and germination index of the small seeds in Dagang were the lowest,and the germination time was the longest..By studying seed germination,seedling traits and offspring seed traits of an annual true halophyte Salicornia europaea,we found there were significant differences in response to temperature,salinity,and light in Salicornia europaea seeds from different provenances.The influence on the offspring plants produced by the dimorphic seeds was significant and was changed some seed traits of their offspring.The salt tolerance of the dimorphic seeds was also different.The plants pass through niche differentiation at different stages of life history and the number of offspring seeds.The combination of between seed size and number,stable investments,and maternal effects of germination may ensured that the Salicornia europaea population can be maintained and regereated in unpredictable environments.