Effect Of Salt Stress On Seed Germination And Seedling Growth Of Cucumber

In this paper, according to the soil secondary salinization increasingly serious，thecomponents of salt in greenhouse soil and the effects of different kinds of salt stress onphysiological metabolism characteristics in germination and seedlings of cucumber wereinvestigated, the main results as follows:1. The salinization in greenhouse soil of different cultivating years of main cucumberplanted cities in Shandong province was studied. The results showed that；the content ofsoluable salt in greenhouse was much higher than outside and Ca2+、Mg2+、NO3-and SO42-arethe main ions. The large content of these ions may be the main reason for soil secondarysalinization.2. This study is about the effect of5different concentrations of K2SO4、MgSO4、Mg(NO3)2、Ca(NO3)2、CaCl2and MgCl2on the germination of C07cucumber seeds. Theresults showed that: Mg(NO3)2has the most significant damage effect, followed by Ca(NO3)2and MgSO4. With the increase of salt concentration, Gr, Gf, Rgr,Gi decreased, Rir increasedand the difference of all these indicators reached significant level at the concentration of100mmol/L. From the study of the effect of100mmol/L Mg (NO3)2on the germination of111different types of cucumber seeds:‘EPT’ had the strongest salt stress tolerance, followed by‘SCNTT’,‘SCLGT’and ‘NCTT’.3. Taking3different kinds of cucumber cultivars ‘XintaiMici(NCTT)’,‘SJ31-1(EPT)’and ‘Lubai19(SCWT)’as test materials, a solution culture experiment was conducted to studytheir growth and antioxidative enzyme activities under the stresses of Mg(NO3)2and NaCl. At50and75mmol/L of Mg(NO3)2or100and125mmol/L of NaCl, the growth and theantioxidative systems of the seedlings were inhibited, and the salt injury index of ‘SJ31-1’was the smallest, the decrement of biomass and SOD, POD and CAT activities beingsignificantly lower than those two cultivars. Under the stress of high concentrationMg(NO3)2(75mmol/L), the SOD, POD and CAT activities of the three kinds of cultivars werelower and the content of free prolin and MDA were much higher as compared with the highconcentration NaCl (125mmol/L) treatment, suggesting that the damage of Mg(NO3)2stresson cucumber seedlings was higher than that of NaCl stress. Among the3cultivars,‘SJ31-1’ had the strongest salt stress tolerance, followed by ‘Xintaimici’ and ‘Lubai19’.