| This experiment used three winter lotus cultivars‘Donghonghua’,‘Xuelihong’and‘Aoshuang’as test material with the control‘Yulourenzui’during natur-al overwintering, explored their morphology and physiological and biochemical chan-ges,analysed their cold resistance and dormancy characteristic and comprehensiveevaluation about their cold resistance and dormancy degree was conducted,thosecould be applied in introduction, cultivation,extension and annual production ofwinter lotus．The main results were described as follows：(1)The result showed the disappearing of winter lotus leaf and bud was clearlylater than the control with the temperature drops,and their subterraneans were alwaystenuous,but not intumescent,that meaned the winter lotus cultivars had greatertemperature range to low temperature,and stable habits of tenuous subterraneans,notgot obviously intumescent for low temperature and dormancy．(2)The four osmoregulation substances such as soluble sugar,starch, solubleprotein and free proline played a role in common．Compared with the control,thewinter lotus had low cold resistance with significantly lower level of osmoregulationsubstances,and variation tendency of these four osmoregulation substances amongwinter lotus cultivars were overall consistent,the change of soluble sugar and solubleprotein content was shown as “down-up-down”, the change of starch and free prolinecontent was shown as “up-down”．Through the coordination of superoxide dismutase, peroxidase and catalase,forthe winter lotus cultivarts,the free radicals and the damaged degree got less and lessin their subterraneans．There were significant differences for their protective enzymebetween winter lotus,and the activities of winter lotus superoxide dismutase andcatalase were significantly lower than the control and the peroxidase activity of“Aoshuang” was higher than other cultivars; and the variation of superoxidedismutase and catalase activity both rose at beginning then declined, the variation ofperoxidase activity were “up-down-up”．Throughout the overwintering process,for the winter lotus cultivars,the malondi- aldehyde content showed an earlier raised and later decreased state and obviouslyhigher than the control,thus they got injured more badly; in the overall levels,therewere significant differences amomg winter lotus,and the injured level from low tohigh was‘Donghonghua’with the lowest level,‘Aoshuang’and‘Xuelihong’．Through comprehensive evaluation about their cold resistance,winter lotus hadweaker resistant ability than the control,and the size relationshipsize about theirresistant ability from strong to weak was ‘Aoshuang’,‘Donghonghua’and‘Xuelihong’;from the cluster analysis result,the four cultivars could be divided into two largecategories those were ‘Yulourenzui’ with strong resistance and winter lotus with weakresistance,and three small categories those were‘Donghonghua’and‘Xuelihong’withthe weakest resistance,‘Aoshuang’ with the moderate resistance and ‘Yulourenzui’with the strongest resistance．The first half of November was fast accumulation period of starch in the winterlotus subterraneans, the free proline content gone up fast,but the soluble sugar contentwas a little low and the soluble protein content also descended; with the finishingaccumulation of starch and the low temperature coming,the starch was hydrolyzeedconstantly, the content of soluble sugar and soluble protein gone up first at differentdegree then declined,and these four kinds of substances all fell down to the lowestpoint at the end of December．The enzymes activites of winter lotus changed consistantly during the overwinte-ring process,for different cultivars the activities of superoxide dismutase and catalaseboth rose to the maxium value on on December1st then gone down,and the activitiesof peroxidase and polyphenol oxidase got to the first crest on November15th,and thenperoxidase activity increased fast,the polyphenol oxidase activity rose slowly．The comprehensive evaluation about dormancy degree showed that the winterlotus had more shallow dormancy,and the size relationship about their dormancydegree from deep to shallow was ‘Aoshuang’,‘Donghonghua’and‘Xuelihong’; thecluster analysis result indicated the four cultivars could be divided into two largecategories those were ‘Yulourenzui’ with the deep dormancy degree and the winterlotus with the shallow dormancy degree,and three small categories those wereDonghonghua’and‘Xuelihong’with the shallowest dormancy degree,‘Aoshuang’ withthe shallower dormancy degree and ‘Yulourenzui’ with the deepest dormancy degree．... |
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