| In this paper, we study the growth,development,physiological and biochemical characteristics of 13 types Cyathula officinalis Kuan under cold-resistance at the seedling stage, analysis the cold-resistance of 13 types by fuzzy administering function and principal component analysis.Preliminary screening three different types of cold-resistance,then screen two types of highly resistant varieties, two types of non-resistant varieties, two types of medium resistant varieties in all of this.Chilling them in different level and study the impact of low temperature on different cold-resistance Cyathula officinalis Kuan growth and development,Photosynthetic physiological characteristics,phytohormone and hardiness physiological characteristics to analysis the mechanisms of cold-resistance. The main conclusions are as follows:1.Analysis the cold-resistance of 13 types by fuzzy administering function and principal component analysis, divided the 13 types of Cyathula officinalis Kuan to three levels by their cold-resistance from weight to weak. Highly resistant varieties: BXR1,BXW1,HYW1;Non-resistant varieties:TQW3,LSW1,MSR; the rest of types are Medium resistant varieties. By the coefficient of variation and resistance variation index analysis, in the 8 evaluation indexes of cold-resistance, Soluble sugar, proline, soluble protein, fresh weight,and plant heightcan truly reflectthe cold-resistance of Cyathula officinalis Kuan.2.Analysis of the mechanisms of cold-resistance declared:compare with the contrast:under the low temperature treatment, the Highly resistant varieties HYW1,BXRlhaslower MDA and relative electric conductivity, this shows that the highly resistant varieties can maintain better water physiology environments, and the damage of their membrane system by the low temperature was lower. With the time of the low temperature treatment, POD activity and SOD activity performance a trend of firstly decreasing and then increasing, the Proline content consistentlyincreasing, But during the 7 days hefore thevelocity of increase was rapid, then the velocity of increase declined.The soluble sugar and soluble proteinwere increasing.The risetimeof soluble protein is faster than the soluble sugar.The results show that low temperature stress may induce the protein expression of highly cold-resistance of Cyathula officinalis Kuan, thus enhancing the activity of protective enzyme and regulating metabolism increase osmotic adjustment substances.improve the cold-resistance of cold-resistance strains. And the activities of protective enzymes of other two sensitive strains and osmotic adjustment substances were lower, and with low temperature stress increases more slowly, the free radical scavenging ability was weak, osmotic adjustment ability was weak, The injury of low temperature stress on cell membrane structure were serious. In 8 ℃ temperature.physiological index performance is not particularly obvious.3.In the low temperature treatment, the Chlorophyll a,Chlorophyll b,Carotenoids’s content and Chlorophyll a/b in Cyathula officinalisKuan Seedlingwere increased,Theincrease of these in highly resistant varieties were higher than that of medium resistantvarieties and non-resistant varieties.the trend of Fv/Fm, ΦPS Ⅱ, qP were decreasing,the trend of NPQ was increasing. Thedecrease of these in highly resistant varieties were lower than that of medium resistantvarieties and non-resistant varieties.Effects of 8 ℃ low temperature on different cold-resistant strains ofphotosynthetic performance was not obvious,the results show thatcold-resistant strains can maintain highlight at temperature lower efficiency, to ensure less injury of protected photosynthetic pigments and photosynthetic mechanism.4.With the level of the low temperature treatment increased, the ABA content and IAA content have increasing trend, the GA content decreasing. The Physiological processes adjusting ability of endogenous hormones in highly resistant varieties were higher than that ofmedium resistantvarieties and non-resistant varieties. |
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