| Fraxinus pennsylvanica XFraxinus velutina,Koelreuteria paniculata,Ginkgo biloba,Acer truncatum,Cotinus coggygria are the most widely used species in gardens of Beijing. The purpose of this study is to use the living plant experimental methods, to find the temperature and humidity of these leaf plants discoloration effect, the result as the theoretical basis for optimization of autumn landscape, also can according to the weather forecast, to direct visitors enjoying the view.The experiment was divided into observation experiments and measurement experiments.Using the camera recorded the phase of the color process. With JL-17temperature and humidity recording instrument recorded the environment acts. TYS-3N plant nutrient speed measuring device measured SPAD values.Researching the relationship of SPAD value and leaves color, temperature and humidity and SPAD value, The results are as follows:1.SPAD values of Koelreuteria paniculata above22, leaves little discoloration. SPAD value between22and20in the color of the leaf, SPAD values below20, the blade has basically been completely discolored.The daily minimum temperature is the main impact on Koelreuteria paniculata autumn leaves changing. Daily minimum temperature between the10℃to5℃accumulated more than10days promotes color changing. The maximum humidity is the second major factor, that in a short time fell more than30%, helps Koelreuteria paniculata leaves color changing.Through analysis,the relationship between SPAD values and the environmental factors is that: Y=19.772+0.307t2(t2for the low temperature)2. Male plants of Ginkgo biloba,its SPAD values above23, leaves little discoloration. SPAD value between23and18in the color of the leaf, SPAD values below18, the blade has basically been completely discolored.The low temperature and daily average temperature are the main impact on male plants of Ginkgo biloba autumn leaves changing. The low temperature below the10℃and the daily average temperature below11℃accumulated more than2weeks promote color changing.Through analysis,the relationship between SPAD values and the environmental factors is that: Y=8.499-0.382t2+1.194t4(t2for the low temperature, t4for the daily average temperature)3. Female plants of Ginkgo biloba,its SPAD values above21, leaves little discoloration. SPAD value between21and17in the color of the leaf, SPAD values below17, the blade has basically been completely discolored.The low temperature and daily average temperature are the main impact on female plants of Ginkgo biloba autumn leaves changing. The low temperature below the10℃and the daily average temperature below15℃accumulated more than2weeks promote color changing.Through analysis,the relationship between SPAD values and the environmental factors is that: Y=8.167-0.441t2+1.174t4(t2for the low temperature,t4for the daily average temperature)4. F.pennsylvanica×F.velutina has long green period, changing color later.howerver the color of autumn leaf is poor.lt can be used as prolong green period species so as to extend the autumn landscape in Beijing.The high temperature and the temperature difference between day and night are the main impact on Fraxinus chinensis autumn leaves changing. The high temperature below the18℃and the temperature difference between day and night below10℃accumulated more than ten days promote color changing.Through analysis,the relationship between SPAD values and the environmental factors is that: Y=8.975+0.724t1-0.237t3(t1for the high temperature,t3for the temperature difference between day and night)5. SPAD of Cotinus coggygria values above25.5, leaves little discoloration. SPAD value between25.5and24.5in the color of the leaf, SPAD values below24.5, the blade has basically been completely discolored.Sunlight and the daily average temperature are the main impact on Cotinus coggygria autumn leaves changing, in sunny place. The daily average temperature below13℃and the low temperature below10℃,accumulated more than two weeks promote color changing. At the same time, the temperature difference between day and night higher than10℃, however it is not the main factor.Through analysis,the relationship between SPAD values and the environmental factors is that: Y=15.89+0.561t4(t4for the daily average temperature)6. Acer truncatum autumn leaves change color situation is more complicated. At the same place and the same time, Acer truncatum change color difference.The daily average temperature is the main impact on Acer truncatum autumn leaves changing. The daily average temperature below the12℃C accumulated more than12days promotes color changing.Through analysis,the relationship between SPAD values and the environmental factors is that: Y=17.595+0.341t4(t4for the daily average temperature)... |
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