| Nitrogen fertilizer is the largest and most widely used fertilizer. But abuse nitrogen fertilizer is a very common phenomenon, and the efficiency is not high, then cause the waste of resources. So it is very urgent and important to look for a fast and convenient monitoring of nitrogen fertilizer . Numerous domestic and abroad studies show that in the same environment conditions, canopy temperature may reflect the growth and metabolism of physiological status of crop, and also canopy temperature is directly related to production. Canopy temperature is expected to be reflected in physiological and metabolic state as a fast, real-time, accurate ecological indicator. Evaluation of the merits may be as a means of fertilization, there will have a great potential in the objective of the information obtained, rapid, quantitative, and precision agriculture. But there was less domestic and foreign research on the nitrogen effect on canopy temperature ,and conclusions are different. Many wheat genotypes were divided into three types according to filling stage canopy temperature, namely, cold type (filling mature canopy temperature during the sustained low genotype), warm-type (continuous high canopy temperature gene type) and intermediate (canopy temperature instability, the larger variation of other genotypes). There was no study about this three kinds of temperature-type wheats whether reaction the same under nitrogen treatment. And there was much more studies about the canopy temperature of filling stage ,less studies about the other stages. In this paper, 0kg / hm2 (N0), 120 kg / hm2 (N120), 240 kg / hm2 (N240), 360 kg / hm2 (N360) four N treatment was studied on cold type wheat Shaan 229, warm-type wheat NR9405, intermediate wheat varieties Xiaoyan 22, the jointing to maturity of three canopy temperature during the filling stage, the net photosynthetic rate, stomatal conductance, transpiration rate, chlorophyll content, soluble protein content, flag leaf water content, MDA .In different parts of wheat translocation of dry matter, yield and its components, as well as filling of various biological traits and the relevance of canopy temperature. The major findings are as follows:(1) Increasing N reduces the wheat canopy temperature, the jointing stage, booting - flowering and grain and the average decreased 0.9℃, 1.2℃and 2.4℃,there was an upward trend with the growth of wheats. The three nitrogen the canopy temperature difference was not significant in jointing stage; booting - flowering overall performance of the N240 treatment canopy temperature minimum, N120 and N360 were not significant; pre-filling N360> N120> N240, differences were between 0.1 ~ 0.6℃, the late stage general for N120> N240> N360, difference were between 0.1 ~ 1.5℃. Cold type wheat Shaan 229 was more sensitive to nitrogen fertilizer, under nitrogen treatment the canopy temperature difference was large than N0; NR9405 and Xiaoyan 22 are different in different growth stages, the jointing stage and filling stage NR9405 canopy temperature under the nitrogen lower rate than Xiaoyan 22, booting - flowering opposite. Three canopy temperature differences among varieties are largest in late stage, but wheat cold, warm type does not change with the nitrogen changes.(2) Nitrogen can increase the water content of wheat flag leaf chlorophyll content, net photosynthetic rate, stomatal conductance, transpiration rate, soluble protein content, nitrate reductase activity, decreased MDA content in flag leaves of different temperature type of comparison, and basic performance of the middle wheat Xiaoyan 22 largest , wheat Shaan 229 second, warm-type varieties NR9405 is the least (the opposite trend of the soluble protein content). N treatment significantly different than N0,but N treatments were not significant.(3)With the nitrogen increasing, Varieties of the grain yield per plant, biological yield, grain assimilated inputing after anthesis increasing; The total dry matter after flowering of cold type wheat Shaan 229 was larger than warm and intermediate varieties NR9405 and Xiaoyan 22. Three varieties of wheat in the N240, the total dry weight of transiting is the largest, dry matter translocation and rate of stem is the largest. Economic factors of Xiaoyan 22 was increased after nitrogen fertilization, Cold varieties Shaan 229 have small responsive to fertilization. The economic factor does not increase with the amount of change in N. Theoretical yield of cold type wheat Shaan 229 with the increasing of nitrogen, to Significant differences, The intermediate-type wheat wheat warm increase among treatment N120 to the N240, in the N240 and N360 it is not significant. Increasing nitrogen application can increase the number of spikes and spike. And 1000 grain weight under N0 was the greatest, 1000 grain weight reducting by nitrogen increasing.(4)In filling stage, canopy temperature and water content, chlorophyll content, Pn, Cd, Tr, soluble protein content of flag leaf of wheat were highly significantly negatively correlated, it is the largest in the post-filling; In late filling stage, the NR content and canopy temperature was also significantly negatively correlated; MDA was positively correlated with canopy temperature, and it is largest in the late filling stage. In Various periods, canopy temperature and grain yield per plant, biomass was significantly negatively correlated, and it is significant negative correlation with the theoretical yield, the rate of correlation is the largest; To the components of Yield, grains per panicle,panicles and canopy temperature of different periods is significant in a negative correlation, at late jointing and filling, it is the largest correlation, jointing of canopy temperature have a very significant positive correlation, but 1000 grain weight and canopy temperature of booting and flowering have a significant positive correlation. |
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