Study On The Physiological Response And Adaptation Mechanism Of Hot Pepper Under Salinity Stress

The large area of soil salinity and the secondary salinization of inland because of inappropriateirrigation of the arid and semi-arid areas is serious problem constraining production and the ecologicalenvironment construction. Worldwide saline area is about one-third of land. And more than 100 countriesare suffering from varying degrees of salinity against. In China, there is also a large area saline. Justin westof northeast the salinity land account for 13.7ï¼…of the total area and is constantly expanding, worsening.Currently the study of plant salt tolerance capability concentrate mainly in field crops and vegetable cropswere concentrated mainly in tomatoes, cucumbers, and the peppers are studied less. Pepper is world wieldvegetable, which production and consumption are considerable quantities. Pepper is not only suitable forfield cultivation, but also suitable for protected cultivation and is the main vegetable production. West ofJilin Province is the main pepper-producing area of this province as well as the whole country's importantpepper-producing area, but salinity is affecting western pepper industrial development. Therefore, the studyof pepper growth and development and adaptation mechanism in salt tolerance capability, discussionphysiological reaction of plants in saline soil, have great significance for cultivating salt tolerance breedingand rational use of salt soil resources.This test with different concentrations of Na₂CO₃ and NaHCO₃ simulate western Jilin salinityconditions on the pepper seeds bud period, seeding period and field period for the salinity stress. The resultindicates that the pepper biological response is basically consistent in bud period, seeding period and fieldperiod. Seed germination potential, hypocotyls length, shoot root and the lateral root and its gradingnumber and percentage of cotyledons is negatively correlated with salinity stress. Two kinds of salinitystress impacting on the germination of varying degrees are different, but the trend is consistent. Whenconcentration of Na₂CO₃ is greater than 20mmol/L and concentration of NaHCO₃ is greater than 40mmol/L,seed germination is inhibited obviously. Different kinds of concentration of salinity stress havesignificantly inhibited effects on the pepper growth, but the effects are different. Pepper is very sensitive inthe process of growth to salt stress. The victim leaves state, biomass; ratio of root to shoot is the most directand most reliable indicators on the ability to adapt. Salt stress reduces dry weight of roots, stems, leavesand fruits and ratio of root to shoot. Base on several indicators of changes in the law and comprehensiveanalysis, the salinity stress inhibition degree largest from high to bottom is Na₂CO₃, Mixed stress andNaHCO₃. RWC is apparent downward trend relative to salinity stress and root activity. The chlorophyllcontent first rises and then drops with stress concentration and time extend, and lower than the control. Salt stress lowers the pepper production, and affects fruit quality. These test results show that Na₂CO₃and NaHCO₃ stress improve the Vc content and increase organic acid content and lower capsaicin andpepper red pigment content.Test results show that salinity stress makes membrane permeability higher and selectivity lower andthe more time the greater the degree of injury. Meanwhile K⁺ Na⁺ content changes with the membranepermeability changes is consistent, which indicates the changes of K⁺ Na⁺ absorption directly relate to themembrane permeability increasing and selectivity decreasing. K+/Na+: with the increasing of saltconcentration, the ratio of K⁺/Na⁺ is apparent downward trend. And Ga²⁺Mg²⁺ contents are decrease.Salinity stress make osmotic (proline, botanies organic acid) content, antioxidant substances (ASA,GSH, VE), the protective enzyme (POD, SOD, CAT) increase, which have the same changes with themalondialdehyde (MDA).