| Welsh onion seeds has a short storage life, and seeds vigor is lost quickly, which inconveniences the production. So it is an urgent problem during the production and germplasm resources'preservation of welsh onion seeds to research welsh onion seeds'aging mechanism, to explore an effective method to improve the seed vigor and prolong seed life easily and economically.The trial materials was welsh onion seeds in this experiment. The experiment studied aging and deterioration mechanism of welsh onion seeds by using artificial aging method and the effects of different priming treatments on improvement of seed vigor and welsh onion seedlings'physiological and biochemical changes.This experiment treated welsh onion seeds at RH100%, different temperature (40℃, 43℃) and different aging time (0d-6d). The results showed that at the same temperature, seed vigor declined gradually, while seeds'malondialdehyde (MDA) and soluble sugar of seeds lixivium increased gradually,and electrical conductivity (EC) of seeds lixivium rised after a brief fall with prolonging of the aging time; at different temperature, the higher the temperature, the faster seed vigor dropping and the greater MDA and soluble sugar increasing.Polyethylene glycol (PEG-6000), salicylic acid (SA) and calcium nitrate (Ca (NO3) 2 ? 4 H2O) was designed to two-factor randomized block with six concentration levels with six levels of priming time .The check was to treat 12h by water. Seed was primed at 20℃for finding the best concentration and priming time of different single-agent treatment. The results showed that at the same time, a relatively low concentration can significantly seed vigor, seed vigor gradually increased with the concentration gradually increased, and to a certain level the seed vigor lower rate increased with the increasing of concentration, until a inhibition; at different time, the longer time the greater inhibition on seed vigor . 24h×A3 (20%) treatment of PEG was the optimum combination, B3 (0.05mmol / L)×24 h of SA had the best effect, 24 h×C2 (10mmol/L) of Ca (NO3)2 had the best effect on increasing welsh onion seeds'vigor, next is treatment 24h×C3 (15mmol/L).On the basis of the single-agent trial , the 3 best treatmens of the 3 single-agent were designed to orthogonal experiment, and the optimal treatment combination was selected. After priming, 8 treats significantly improved seed vigor compared with CK except D9 (P3S3Ca2: 25%×0.1mmol/L×10mmol/L), and D2 (P1S2Ca2: 15%×0.05 mmol/L×10mmol/L) reached the 0.01% significance level. SA's R is bigest in the 3 factors of combination ,so SA played a major role, followed by the PEG, Ca (NO3) 2. Three factors'difference between the treatment did not reach significance level.Choosing respectively 3 optimal single-agent treatments and two combination treatments, the seedling emergence experiment was carried out in field after priming 24h and contrasted with seed which was treated 12h by water. The result showed that all of seeds which were primed increased the seedling emergence rate than CK, in addition the speed of emergence also increased compared with CK except E1 (PEG: 20%×24h), E2 (SA: 0.05mmol/L×24h) and E3 (Ca(NO3)2: 10mmol/L×24h) achieved significant difference compared with CK; the root vigor had a decrease compared with CK while the chlorophyll content only E1 increased and reached a significant difference than CK, and all of other treatments decreased than CK; SOD and POD had a substantial increase than CK reached a very significant difference with CK, which indicated that seed priming not only promote the emergence, but also increased the resistance of the seedlings significantly.
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