Effects Of Salt Stress On Seed Germination And Physiological Characteristics Of Seedlings In Pepper (Capsium Annum L.)

In order to study the effects of different types of salt on pepper (Capsium annum L.)seedlings and seed germination ,to research its physiological mechanism, ion uptake, and photosynthetic characteristic, Longjiao 2 as basic testing material was treated by NaNO3,Na2SO4 and NaCl at seed stage and 6-true leaf stage .The main results were showed as follows:1. Compared with CK, all the three types of salt with different concentrations decreased seed germination rate and delayed germination process of pepper. Germination index and vigor index were all decreased as salt concentration increased.2. Under the conditions of this experiment, in the same treatment type, the higher salinity level was, the higher inhibition degree to the height of plants and the area of leaves in pepper were.3. All the treatments of three types salt increased the membrane permeability, content of MDA and soluble suger with the increase of salinity and prolonging of time.4. The root activities of pepper seedlings in CK treatment were inhibited. Under NaCl stress, relative water content in root decreased, while that of treated with NaNO3 and Na2SO4 increased. From those, we can conclude that the root cells of pepper treated with NaCl lost water, and that of treated with NaNO3 and Na2SO4 did not .5. Na+ content and Na+ / K+ in different organs were increased and K+ content was decreased under NaCl and Na2SO4 stress. In NaNO3 treatment, K+ content of all organs was increased, Na+ / K+in stems and leaves were increased.6. The effect of chlorophyll concent in leaves as follow: It was decreased in NaCl treatment. In Na2SO4 treatment, it was increased firstly then decreased. In NaNO3 treatment, it was increased when the salt concentration was lower than 100mmol.L-1 and decreased when that higher than 100mmol.L-1 .7. In higher concentration salt treatments or at longer time with lower concentration treatments, all the three types of salt increased Fo of leaves and that showed the photoinhibition occurred in the photosystem II of pepper. At the same conditions, Fv/Fm of photosystem II decreased. In addition, the activities of ATPase were decreased. It seems showed that the inhibition effect on the light reaction of pepper in all three types of salt was earlier than that on the dark reaction.8. The higher salt concentration was, the lower photosynthetic rate, Hill reaction rate and chloroplast ATPase activities were, and the worse chloroplast ultrastructure else, no matter what salt involved in this experiment. The reasons of three types salt made the...