Evaluation Of Low-temperature Adaptability Of Different Lily Varieties

To carry out the introduction of garden plants in Northeast China,the selection of varieties with high adaptability to low temperature environment is the key to successful introduction.In this paper,13 lily species introduced in Shenyang were studied.Their growth and nutritional reproduction indexes after overwintering in open field cultivation were investigated;the effects of different burial depths of seed balls on overwintering survival and growth of lilies were studied;and a preliminary study on the relationship between leaf anatomical structure and cold resistance of varieties was conducted.The low-temperature stress test was conducted in an artificial climate chamber for lily varieties:the control temperature was 25℃/15℃（day/night）（CK）,and the low-temperature stress incubation temperature was 15℃/5℃（day/night）;the time gradients of low-temperature stress were 1d（D1）,3d（D2）,and 5d（D3）;the treatment was rewarmed at the control temperature for 2d（D4）after 5d of low-temperature stress;the physiological effects of low-temperature stress and rewarming were measured.The physiological indices of different species of lilies under low temperature stress and rewarming conditions were determined.The results were as follows:1.Results of open field cultivationThe first seedlings of the introduced varieties in spring were D（Golden Matrlx）and B（Orange Matrlx）.The survival rate of different varieties in open field cultivation varied greatly,with the highest survival rate（99.2%）for variety C（Red twin）and the lowest survival rate（0%）for J（Tiber）.nutritional fertility was significantly higher for G（Maldano）and lowest for two varieties F（（E.H.Wilson）Raffill）and H（Conca d’Or）.After studying the leaf anatomy,it was found that the leaf tightness was higher in E（（Regel）Baker）,M（Eyeliner）and F（（E.H.Wilson）Raffill）.Under open field cultivation,the spring net photosynthetic rate was ranked from highest to lowest as B（Orange Matrlx）>L（Dauricum Ker-Gawl）>E（（Regel）Baker）>A（Asopus）>I（Robina）>F（（E.H.Wilson）Raffill）>M（Eyeliner）>H（Conca d’Or）>C（Red twin）>D（Golden Matrlx）>K（Viviana Zantriana）>G（Maldano）.2.Changes in physiological indicators of different lily species under low temperature stressThe electrical conductivity（Rec）of each variety showed different patterns of change with the prolongation of low temperature stress,in which M（Eyeliner）showed a highly significant increase in electrical conductivity under each low temperature time gradient compared with the control（P<0.01）.The percentage of varieties with elevated MDA content compared to the control was 84.62%,76.92%and 92.31%under D1,D2and D3 treatments,respectively.After rewarming,the Rec continued to be elevated in53.85%of the varieties;69.23%of the varieties had MDA contents still higher than the values on the 5th day of stress.The proline（Pro）content of 69.23%varieties increased highly significantly（P<0.01）with increasing stress time.Soluble sugar（SS）content continued to increase with prolonged low temperature stress in only 23.08%of the varieties.Soluble protein（SP）was significantly lower（P<0.05）in the vast majority of varieties（76.92%）.The SOD and POD activities of all varieties showed an increasing trend with the increase of low temperature stress time.The net photosynthetic rate of all tested lily varieties decreased with increasing time of low temperature stress,and 38%of the varieties showed a significant（P<0.05）decrease in net photosynthetic rate at all low temperature treatment gradients.After rewarming,proline（Pro）content decreased in 76.92%of varieties compared to 5 days of low temperature stress;SS content increased more significantly in 61.54%varieties;SP content increased significantly in 46.15%varieties and decreased significantly in 30.77%varieties（P<0.05）;POD decreased in all varieties,but SOD continued to increase in 76.92%varieties.After rewarming treatment,the net photosynthetic rate of all varieties of lilies recovered and was significantly higher than that of D₃ treatment,but still all were significantly lower than the control.3.Comprehensive evaluation results of cold resistance of different varietiesBased on the survival rate,nutrient reproduction capacity,net photosynthetic rate,leaf tightness and physiological indexes of lily species under open field conditions,the cold resistance of different species of lilies was analyzed by using the affiliation function,and the comprehensive cold resistance of lilies was obtained in the following order:B（Orange Matrlx）>E（（Regel）Baker）>G（Maldano）>L（Dauricum Ker-Gawl）>M（Eyeliner）>F（（E.H.Wilson）Raffill）>A（Asopus）>C（Red twin）>I（Robina）>D（Golden Matrix）>H（Conca d’Or）>K（Viviana Zantriana）>J（Tiber）.Based on the results of the above study,the following introductions were given:priority was given to the introduction of Orange Matrlx,（Regel）Baker,Maldano and Dauricum Ker-Gawl;while Tiber could not be adapted and was not recommended.