| More research about different nitrogen levels in winter wheat growing period of photosynthetic characteristics and yield formation had been done,but much more focused on a specific study of leaves,especially the flag leaf.As the leaf nitrogen content in different leaf had some differences in the distribution,nitrogen level is also bound to different affect.Leaf chlorophyll content,photosynthesis and chlorophyll fluorescence parameters such as value, but on the one hand,rare research reports.Through field trials with a view to answering these questions,revealing the reasonable application to increase output in real terms,while winter wheat for a reasonable diagnosis of leaf nitrogen to provide a basis for the determination.The research used the Eun-Orthic Anthrosols soils and Xiaoyan No.22 as soil samples and test crops.This experiment was conducted to study the effect of nitrogen on SPAD and photosynthesis rate of different leaves and Chlorophyll Fluorescence Characteristics of winter wheat at different leaf position.The results were showed as follows:1.There was significant difference of SPAD among different leaves under different nitrogen level.The order of leaves in SPAD were flag leaf＞the second leaf from top＞the third leaf from top＞the forth leaf from top.Therefore,the distribution of SPAD and photosynthesis rate among leaves of wheat plant was relatively stable,and was hardly affected by nitrogen level.2.The SPAD value increased with nitrogen level rising from 0 kg/ ha to 90 kg/ ha,but it changed little while above 90 kg/ ha.The character was significant at the third leaf from top. With the increasing nitrogen level,there was no difference between SPAD and photosynthesis rate of different leaves,which had relation with the increasing nitrogen.The bottom leaves had turn nitrogen to the top leaves,which was favorable for cutting consenescence rate of bottom leaves.3.The order of distribution characters of leaves in photosynthesis rate was flag leaf＞the second leaf from top＞the third leaf from top＞the forth leaf from top.This was the same as the order of distribution characters of leaves in SPAD.4.The correlative analyses of SPAD and photosynthesis rate at different leaf location was indicated that there were significant correlation among flag leaf,the second leaf from top and the third leaf from top,except for the forth leaf from top.This had showed the higher or lower SPAD had effective reflect the ability of photosynthesis in winter wheat. 5.The order of the biggest Chlorophyll Fluorescence with different disposal was flag leaf＞the second leaf from top＞the third leaf from top.When the nitrogen level was 90-135 kgN/ha,Chlorophyll fluorescence in the greatest value Fm,the different treatment of wheat is basically for the flag leaf＞the second leaf from top＞the third leaf from top,the amount of nitrogen applied for 90-135 kgN/ha,wheat leaves of different places to achieve maximum Fm. Different nitrogen levels in wheat plants in different parts of the vertical direction of the chlorophyll fluorescence of the initial value of Fo,for the performance of the flag leaf＞the second leaf from top＞the third leaf from top,the amount of nitrogen applied for 90-135 kgN/ha,wheat leaves in different places Fm Maximum.Different nitrogen levels in wheat plants in different parts of the vertical direction of the variable chlorophyll fluorescence value of Fv,the winter wheat deal with different nitrogen trend did not change significantly.6.Different levels of nitrogen under winter wheat plants in different parts of the vertical direction of the most PSⅡphotochemical efficiency,basically for the performance of the Fv/Fm flag leaf＞second leaf from top＞the third leaf,and the same function in the leaves of different nitrogen fertilizers to deal with the biggest photochemical efficiency Is not very different.Winter wheat in different parts of PSⅡpotential activity(Fv/Fo)is also essential for the performance of the flag leaf＞the second leaf from top＞the third leaf from top. |
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