Effects Of Storage Methods On Seed Characters And Saline-alkali Tolerance Of Nelumbo Nucifera And Euryale Ferox Seed

Wetland aquatic economic plants are an important element of wetland vegetation restoration,as well as an important guarantee for the maintenance and sustainable development of wetland restoration projects.Nelumbo nucifera and Euryale ferox are typical native aquatic economic plants in the western wetlands of the Songnen Plain,and revealing their tolerance and adaptation mechanisms to saline and hydrological conditions is an important basis for restoring and enhancing their growth quality and yield.The seed germination and seedling growth stages are not only important throughout the reproductive life of wetland plants,but are also very sensitive to abiotic stresses.Therefore,in order to maintain the viability of seeds and improve the resistance to salinity,this study analyzed the changes of seed traits and the characteristics of salinity tolerance at the seedling stage after 240 days of storage in five different ways: dry storage at room temperature,sand storage at room temperature,dry storage at low temperature,sand storage at low temperature and frozen storage,through simulated control experiments,in order to select the optimal seed storage method.By analyzing the soluble protein content,soluble sugar content,starch content,relative conductivity of seed leachate,malondialdehyde content and germination potential and germination rate of seeds of seeds of Nelumbo nucifera and gorgonians under different soda saline stress intensities in five different storage methods,the effects of different storage methods on seed traits and seed viability of seeds of Nelumbo nucifera and Euryale ferox were initially revealed.The effects of different storage methods on the salinity tolerance of seeds and seedlings of Nelumbo nucifera and Euryale ferox were evaluated by the index analysis of shoot length,fresh weight,soluble sugar content,proline content,superoxide dismutase activity and peroxidase activity of Nelumbo nucifera and Euryale ferox seedlings treated with different storage methods under different soda salinity stress intensities.The main findings of this study are as follows.(1)The Euryale ferox of gorgonian seeds belongs to mixed dormancy,with both sclerotia and embryo dormancy in the seed coat.Sand storage significantly increased the relative conductivity of the leaching solution of Euryale ferox seeds and changed the seed coat permeability.The malondialdehyde content of low-temperature sand storage Euryale ferox seeds was significantly higher than that of other storage methods,making it the only treatment that allowed normal germination after storage.Sand storage broke the seed coat hardening dormancy of Euryale ferox seeds,while low temperature broke the embryonic dormancy of Euryale ferox seeds.Low temperature sand storage is an important way to break the dormancy of Euryale ferox seeds and improve the salinity tolerance of Euryale ferox seeds.(2)The Nelumbo nucifera seed coat is thick and firm,and the temperature under different storage methods is the main factor affecting Nelumbo nucifera seed traits and seedling growth under saline conditions.Different storage methods have an effect on Nelumbo nucifera seedling traits on the intensity of soda saline stress with certain threshold requirements.The soluble sugar content,malondialdehyde content,germination potential,germination rate,shoot length,fresh weight and peroxidase activity of Nelumbo nucifera seeds were higher in ambient storage than in low temperature storage and freezing storage when the intensity of soda saline stress was below 40mmol/L.The resistance of Nelumbo nucifera to soda saline stress was also higher in ambient storage than in low temperature storage and freezing storage.The relative conductivity of Nelumbo nucifera seeds in sand storage at room temperature is lower than in dry storage,and sand storage is more suitable than dry storage for long-term storage of Nelumbo nucifera seeds.For growing seed lilies by sexual reproduction,sand storage at room temperature is more suitable for Nelumbo nucifera seeds of seed lilies.(3)The dormancy mode of Euryale ferox seed belongs to mixed dormancy,which includes both hard seed dormancy of seed coat and embryo dormancy.Sand storage significantly increases the relative electrical conductivity of seed coat and affects seed coat permeability.The content of malondialdehyde in seed of Euryale ferox seed stored at low temperature was significantly higher than that of other storage methods,which became the only treatment method that could germinate normally after storage.Sand storage breaks hard seed coat dormancy of Euryale ferox seed,while low temperature breaks embryo dormancy of euryale seed.Low temperature sand storage is an important way to break seed dormancy and improve seed salt-alkali tolerance.