Study On Cold Resistance Of Six Species Of Spiraea L.

The resourse of Spiraea linn.is excellent ornamental bush due to its special properties and benefits,namely gathering the flower and colorful leaf to appreciate;flourishing flowers have flamboyant color;it blooms in spring,summer and autumn;the foreground of application of Spiraea will be wide at gardening;and it can be widely used in gardening of city forestations.But the Spiraea has limited application at Hei Longjiang province that is cold and dry region,because of climate and other reasons.So the study about the live through the winter ability of Spiraea at the cold region is the key point to apply the Spiraea as forestation plant at Hei Longjiang and northeast region.There are six species of Spiraea were used as experimental material in this project and they have different cold resistance ability.These six species of Spiraea are S.×bunmalba cv. Goldmound,S.×bunmalba cv.Goldflame,Spiraea media Schmidt.,Spiraea Salicifolia L., Spiraea thichocarpa Nakai,Spiraea fritschiana Schneid respectively.However the natural cold acclimation,the artificial cold acclimation,without cold acclimation process were used as experimental methods to study the relationship between variety trends of morphological and physiological information of six species of Spiraea and cold resistance ability.And then,the Logistic equation,subjection function and clustering analysis that are mathematic analytical methods were considered to rank and classify the different cold resistance ability of these six species of Spiraea.Synchronously,the grade of cold resistance ability of these six species of Spiraea was discussed during alternated period in spring and autumn;and this period is alternation between freeze and thaw.Finally,few conclusions were indicated by this project study;and they are sum up as follow:1.Spiraea fritschiana Schneid and Spiraea media Schmidt.have better morphological adaptability on low temperature situation.SR and leaves' stoma density of six species of Spiraea' anatomized conformation are suitable as appraisable data to determine the cold resistance ability of these six species of Spiraea.But periderm proportion,xylem proportion and phloem proportion of six species of Spiraea' anatomized conformation are not suitable.2.From this project,the Semi-lethal temperature(LT₅₀) of S.×bunmalba cv.Goldmound,S.×bunmalba cv.Goldflame,Spiraea media Schmidt.,Spiraea Salicifolia L.,Spiraea thichocarpa Nakai,Spiraea fritschiana Schneid can be determined;and they are-20.7,-23.7,-26.8,-26.1,-27.2 and-32.6 respectively.However the cold resistance ability of these six species of Spiraea can be classified into two grades after Semi-lethal temperature(LT₅₀)clustering analysis;The first grade is S.fritschiana Schneid,it have higher cold resistance ability than others;the second grade is other species of Spiraea.So these six species of Spiraea can be applied as gardening plant on the south of Hei Longjiang Province;but only S.fritschiana Schneid can be applied on the north low temperature of Hei longjiang province.3.During cold acclimation processes,the gradual increasing of soluble protein content,the gradual increasing of the protected enzyme SOD activity and the rise of ABA content have extended effect during the natural low temperature intimidating process.The IUFA of these six species of Spiraea increased,when they lived through the winter;the fatty film still has fluidity at the lower temperature and they still can carry through physiological function.But there is not direct relationship between cold resistance ability and the IUFA of these six species of Spiraea.The natural cold acclimation is the most effective approach that increasing the cold resistance ability of these six species of Spiraea.4.Via the protein spectrum analysis of six species of Spiraea that were dealt with the different cold acclimation,the cold resistance ability can be reflected by protein expressed quantities of 64KD,55KD and 45KD.5.In the alternation from freeze to melt period in spring and autumn,the related degree between the various index and cold resistance ability of these six species of Spiraea has a following sequence:content of PRO＞content of soluble carbohydrate＞content of ABA＞content of soluble protein＞activity of SOD enzyme.The other five species of Spiraea except Spiraea thichocarpa Nakai have better cold resistance ability in autumn than in spring;in another word,the climate characteristic of sprin have worse damage on the most species of Spirarea.And In the alternation from freeze to melt period in spring and autumn,the special different protein express appear in the protein spectrum of six species of Spiraea.6.According to subjection function value analysis about two aspects,which are the influence of the natural,artificial and without cold acclimation to the cold resistance ability of six species of Spirarea as well as the subordinate value of morphological anatomized conformation,it can conclude the cold resistance ability sequence of 6 Spiraea trees from strong to week is Spiraea fritschiana Schneid,Spiraea Salicifolia L.,Spiraea media Schmidt.,Spiraea thichocarpa Nakai,S.×bunmalba cv.Goldmound and S.×bunmalba cv.Goldflame.And this conclusion is similar with the conclusion of the Semi-lethal temperature(LT₅₀).The thesis systematically study on the cold resistance ability of six species of Spirarea in aspects of anatomical structure,photoresponse curve,plasma membrane system indicators, osmo-coditioning material,hormone ABA content,changes and expression of adaptive protein under cold stress and so on,which is the first time in our country.