| The application of the color-leafed trees in landscape garden design is becoming more and more extensive today.Malus ‘Royalty' and Malus ‘Guanghui' are the familiar species for landscaping.In order to explore the relationship between the leaf color change of Malus and endogenous substances,Malus ‘Royalty' and Malus ‘Guanghui' in national habitat were used to do some research on the following aspects:1.Observe and study the changes of the leaf color during the whole growth period,and determine chlorophyll content,anthocyanin content,carotenoid content,soluble sugar content and PAL activity;2.Discuss the changing trends of chlorophyll content,anthocyanin content,carotenoid content,soluble sugar content and PAL activity with varying degrees of the shading level and different kinds of foliar fertilization,to get different kinds of foliar fertilization have the impact on color-forming mechanism under varying degrees of the shading level,thus offers the theoretical foundation for choosing the location,targeting cultivation management measures and maximizing the trees ornamental value.The main findings are as follows: 1.The study on the ornamental characteristic of Malus ‘Royalty' and Malus ‘Guanghui'Malus ‘Royalty' belongs to concolourous leaf plants,all the pear buds tested in Changchun area began to sprout from April 5,almost all leafs defoliated from October 23,the whole growth period lasted 202 days.The leaves of Malus ‘Royalty' represented fuchsia,only showed green between August 21 and August 26;Malus ‘Guanghui' belongs to the spring colorful plants,all the pear buds tested in Changchun area began to sprout from April 5,almost all leafs defoliated from November 5,the whole growth period lasted 215 days,lasted 15 days longer than Malus ‘Royalty',by the direct observations on leaf color,between May 1 and July 1 the new leaves of Malus ‘Guanghui' showed reddish-brown,then turn to yellowish green,until October 16 the leaves turned to senescence,the color turned to red-orange.2.The digital analysis on leaf colors of Malus ‘Royalty' and Malus ‘Guanghui'(1)Under CMYK color pattern,the K value of the leafcolors of Malus ‘Royalty' is significantly higher than the K value of the leafcolors of Malus ‘Guanghui',the M value of the leafcolors of Malus ‘Royalty' is higher,the C value is significantly lower than the C value of the leafcolors of Malus ‘Guanghui',the Y value of the leafcolors float in 70-100%,the Y value of the leafcolors inferior leaf float in 90-100%,the Y value of the leafcolors of Malus ‘Guanghui's inferior leaf keep within 100% during the whole growth period,the green which Malus ‘Royalty' appear is admix green and yellow,and the main color is green,just as the bright fruit green,but the green which Malus ‘Royalty' appear is admix green and fuchsia,green is the main color,(2)Under Lab color pattern,when a value is positive,the color of leaf is red,a value is negative,the color of leaf is green.During Malus ‘Royalty' growth period,the a value descends into negative numbers during 21 August to 26 August,the rest of the growth period is positive number;the a value of the leafcolors of Malus ‘Guanghui' descends into negative numbers during 1 May to 1 July and October 23 to 30,all agree with the actual observation.The b value of the leafcolors of Malus ‘Royalty' is floating in the range of 30 to 60,the b value of the leafcolors of Malus ‘Guanghui' is floating in the range of 10 to 40,the L value of the leafcolors of Malus ‘Guanghui' is significantly higher than Malus ‘Royalty',means that brightness of Malus ‘Guanghui's leafcolor is much brighter than Malus ‘Royalty',the green is much brighter than Malus ‘Royalty'.3.The study on leafcolors changing of Malus ‘Royalty' and Malus ‘Guanghui' in nature circumstance during the whole growth period showed the changing of chlorophyll-a content in the leaves of Malus ‘Royalty' and Malus ‘Guanghui' would decide the content of chlorophyll,the major reason is the major components of chlorophyll is chlorophyll-a.When chlorophyll content accumulates and the content of anthocyanin going down,the ratio of anthocyanin to chlorophyll goes down,the leafcolors of Malus ‘Royalty' turn green,then chlorophyll content going down and the content of anthocyanin accumulates,the leafcolor shift from green to fuchsia,so the direct cause of the Malus ‘Royalty' leafcolor turn green is chlorophyll content accumulates and the content of anthocyanin going down.When the leafcolor of Malus ‘Guanghui' turn red,the ratio of anthocyanin to chlorophyll at peak levels,at the same time,the content of carotenoid accumulates,in conclusion,the leafcolor changing of Malus ‘Guanghui' is decide by the content of anthocyanin and carotenoid.In the paper,the changing of soluble sugar content is positively correlated with the content of chlorophyll and carotenoid,the changing of soluble sugar content is significantly positively correlated with the content of anthocyanin,is negatively correlated with the content of chlorophyll in the leaves of Malus ‘Royalty',the changing of soluble sugar content is significantly negatively correlated with the content of anthocyanin,is positively correlated with the content of carotenoid in the leaves of Malus ‘Guanghui',so the leafcolor is tightly related to the content of soluble sugar,PAL would control the synthesis of various of pigment could be derived by measuring PAL activity,but PAL is not the only enzyme to decide the synthesis of various of pigment.4.Study on physiological mechanism of leaf color change under shading and foliar –spraying fertilizer for Malus ‘Royalty' and Malus ‘Guanghui'In the paper,only performed degree of shade process on the grafting seedlings of 2 years old,the content order of chlorophyll in the leaves of Malus ‘Royalty' and Malus ‘Guanghui' is 75±5% shading>30±5% shading>complete illumination;the content order of anthocyanidins in the leaves of Malus ‘Royalty' and Malus ‘Guanghui' is complete illumination>30±5% shading>75±5% shading,insufficient illumination would promote the synthesis of chlorophyll and the anthocyanidins degeneration,then have an effect on leaves color.Under different degrees of shading and various kinds of foliar –spraying fertilizer,0.2% KH2PO4 could promote the content of anthocyanin accumulates in the leaves of Malus ‘Royalty' under complete illumination,500 dilution photosynthetic enzymes could promote the content of anthocyanin accumulates in the leaves of Malus ‘Royalty' under 30±5% shading,4% sucrose solution could promote the content of anthocyanin accumulates in the leaves of Malus ‘Royalty' under 75±5% shading.500 dilution photosynthetic enzymes could promote the content of anthocyanin accumulates in the leaves of Malus ‘Guanghui' under complete illumination,4% sucrose solution could promote the content of anthocyanin accumulates in the leaves of Malus ‘Guanghui' under 30±5% shading.0.2% KH2PO4 could promote the content of anthocyanin accumulates in the leaves of Malus ‘Guanghui' under 30±5% shading.The ratio of anthocyanin to chlorophyll significantly improved under foliar –spraying 4% sucrose solution,then obviously promote leafcolors presenting on condition of heavy shading.Foliar –spraying 0.2% KH2PO4 could promote chlorophyll content going down and the content of anthocyanin accumulating,then promote the leaf color rendering. |
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