| The secondary salinization of the facility soil seriously affects the development of the facility vegetable industry.How to alleviate the harm of secondary salinization is one of the hot spots in the research of facility vegetables.Cucumber（Cucumis sativus L.）is one of the important cultivated vegetables in the facility.It is easy to cause continuous cropping obstacles in the cultivation of the plant,which will intensify the secondary salinization of the soil and cause the yield reduction of cucumber.Therefore,studying the salt tolerance of cucumber is of great significance for cucumber production.Many studies have shown that the application of exogenous chemicals can induce plant resistance.Salicylic acid（SA）and Brassinosteroids（BR）are recognized as chemical inducers.The effects of soaking seeds and spraying leaves of SA and BR on seed germination and seedling growth of Cucumber under Ca（NO3）2 stress were studied in greenhouse with"lüdao NO.7"cucumber as test material,Ca（NO3）2 as salt stress factor and SA and BR as inducers.Production experiments were carried out in continuous high-salt soil in greenhouse to provide theoretical and practical basis for high-quality,high-yield and high-efficiency production of Cucumber under salt stress.The main results are as follows:（1）Soaking seeds with a certain concentration of exogenous SA(80 mg·L-1)promoted the seed germination of cucumber,and increased the germination potential,germination rate,germination index,vigor index andα-amylase activity of cucumber seeds under Ca（NO3）2 stress.（2）Different agents and their different application methods(80 mg·L-1SA soaking,150 mg·L-1SA spray,80 mg·L-1SA soaking+150 mg·L-1SA spray and 0.1mg·L-1BR soaking,80 mg·L-1SA+0.1 mg·L-1BR compound soaking)could induce salt-tolerance of cucumber seedlings and alleviate the damage of Ca（NO3）2 stress on cucumber growth and development.Compared with Ca（NO3）2 stress controltreatment,the external source SA soaking treatment had the best effect.Seedling index,photosynthetic pigment content,soluble sugar content,Pro content,superoxide dismutase（SOD）activity,peroxidase（POD）activity,catalase（CAT）activity,stomatal opening of cucumber seedlings,photosynthetic parameters,palisade tissue thickness/sponge tissue thickness ratio ratio were significantly increased.The accumulation of MDA and the stomatal density were significantly reduced.and reaching a significant level.（3）The soaking treatment of SA improved the plant height,stem diameter,number of unfolded leaves and the number of early melons,but had no effect on the first female flower node and the first female flowering melon time in the cucumber seedlings in the continuous cropping greenhouse. |
