| Nandna domestica is a small shrub of wide application in garden.N.domestica'Hongye' is a new cultivar of red-leaf plant,which have higher ornamental value,but its application environment is unclear.A pot experiment was conducted under different shadings(illuminated as CK,30%shading as C1,55%shading as C2,75%shading as C3)to explore the morphological,physiological and biochemical characteristics of two-year-old N.domestica 'Hongye' in order to clarify the light range of the cultivar in landscape application.At the same time,the substance of red color of N.domestica 'Hongye' was preliminarily identified by HPLC.The main results were showed as follow:(1)With the deepening of shading,leaf area of N.domestica 'Hongye' increased significantly,especially when prolonging the shading treatment.When N.domestica'Hongye' was under one month of shading,average leaf area of 75%shading was 1.19 times of that in full light,and continued five months of shading make the difference 1.98 times.Specific leaf weight of N.domestica 'Hongye' decrease with the increasing of shading,and average of Specific leaf weight of 75%shading was 74.2%of that in full sight.Compared with full sunlight,the leaf color of 30%shading was no difference,but leaves of full sunlight appeared anxiety.The red became lighter and green deepened with the shade degrees increasing,leaves of 75%shading were almost entirely green.The leaf color of N.domestica 'Hongye' was better in the sparse shade environment(30%shade degrees).(2)The contents of chlorophyll and carotenoids increased with increment of shading,whereas relative content of anthocyanin decreased,and the activity of PhenylalanineAmmonia-lyase(PAL)reduced.The content of soluble sugar shared no difference between different degrees of shading.With the prolonging of shading treatment,therelative content of anthocyanin increased,especially in Jan.with the increase of>40%.Pattern of soluble sugar were similar to anthocyanin.The activity of PAL dropedwith the prolonging of shading.Contents of chlorophyll and carotenoids increased in full light or in 30%shading,fluctuated smoothly in 55%shading,and increased at firstand then decreased in 75%shading.(3)Content of leaf N was higher when N.domestica 'Hongye' was under 75%shading,and leaf P or K were higher under 50%shading.Content of Ca decreased with the increment of shading.However,Contents of Mg,Fe had no differences among different shading treatments.(4)Correlation analysis showed that anthocyanin content was positively correlated with contents of soluble sugar or PAL or Ca(P<0.05)and was negatively correlated with content of N(P<0.05).Content of chlorophyll was positively correlated with the content of N(P<0.05),and was negatively correlated with the contents of PAL or K or Ca(P<0.05).(5)In October,light saturation point(LSP)of Osmanthus fragrans was 60?mol·m-2·s-1,light compensation point(LCP)was 22.8 ?mol·m-1·s-1,maximum netphotosynthetic rate(Pnmax)was 0.784 ?mol·m-2·s-1,apparent quantum efficiency(AQE)was 0.035,dark respiration rate(Rd)was-0.589 ?mol·m-2·s-1 under the natural light..The shading treatment increased LSP,decreased LCP,and expand the scope of light.Fv/Fm also gradually increased with increment of shading,and qP and ETR were larger and more conducive to photosynthesis under 30%and 55%shading.The net photosynthetic rates were lower under full light and 75%shading,which show that too strong or too weak light was hard to photosynthesis.(6)In the qualitative detection of anthocyanins of N.domestica 'Hongye',6 kinds of commonanthocyanins:Delphinidin(m/z 303),Cyanidin(m/z 287),Pelargonidin(m/z 271),Petunidin(m/z 317),Malvidin(m/z 331)and Peonidin(m/z 301)were not found.However we detected a new substance(m/z 340)and further separation and purification are needed to accurately identify its structure. |
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