| A study on six mustard varieties deterioration seeds was conducted to analyze the changes of physiological, biochemical, and genomic DNA damages during artificial aging. We expected to find the representative physiological and biochemical indexes of seed vigor and the ISSR fingerprints in different aging seeds. The research on the mechanism of seed deterioration would be the guidance for the preservation and storage germplasm of mustard seeds. The results were showed as follows:1.Under the accelerate aging condition(40℃, RH100%), the germination percentage and the vigor index of mustard seeds reduced as the aging time increasing. Datoucai was the poorest aging resistance in the six mustard varieties, the vigor of Datoucai seeds almost disappeared after 6 days treatment. The germination percentage of Qingcai and Xiangjiecai seeds decreased slowly in the early times, and reduced significantly after six days. The changes of activity in different varieties and different treatment times showed that the turning point was six to eight days.2.The correlation between relative conductivity, MDA content and activity index were negatively correlated. Soluble sugar content, soluble protein content, SOD activity, POD activity and vigor index were positively correlated with the proceeding time.①With the aging time going, the relative conductivity increased slowly.②Except Qingpibangcai, MDA content of mustard seeds gradually raised as the degrees of aging increased, and the change in er'cai and Datoucai seeds showed the same trend.③Soluble protein content decreased instably, and it has a slow upward trend in certain time of aging. The time that the content changed were not in the same stage of different varieties. Datoucai, Zhacai and Xiangjiecai changed after 4-6days. Qingcai and Qingpibangcai were 2-4days. No changes were in Ercai;④The activity of SOD and POD were significantly decreaed in the first 2-4 days,then changed slowly. The changes of the activity varied widely in different varieties. Datoucai, Ercai and Qingpibangcai had a relatively high activity at the very beginning, and decreased sharply in aging. Zhacai, Qingcai and Xiangjiecai had very low activity when the aging started, and decreased slowly afterward.3.The result of principal component analysis indicated that the first principal component consist of germination rate, vitality index, relatively conductivity and MDA. This four indicators were closely related to aging, which can be used as the typical mustard seed aging factors. The second component was POD activity, which was certain relativity in SOD acitivity and the content of soluble sugar. The third component was soluble protein.4.The DNA purification method of dry mustard seed with artificial aging was founded in this experiment, the diffreneces were as below:①The solution of Tris phenol:Chloroform:Isoamyl alcohol (25:24:1)was used in this method.②he protein extraction procedure was increased (2 more times than the classic method)③1μL Rnase A was added at the final step5.Six suitable primers were screened (U809, U810, U817, U859, U880, U891) for studying the genomic DNA damages of aging mustard seeds. The specific bands of ISSR were established for the six varieties of mustard seeds with artificial aging. There were two significant that it was found that ISSR-PCR bands of aged seeds were found on high molecular weight region (2000-750bp) and low molecular weight region (250-100bp).Bands of ISSR reduced when the aging prolonged, and it was slight loss of color and even disappeared completely. |
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