| Nitrogen(N),as one of the macronutrients necessary for corn growth,is a key factor that limits plant growth and development and yield formation.In recent years,the large-scale application of nitrogen fertilizer has indeed played an important role in increasing the global corn production,but at the same time,it has also promoted the increase in agricultural production costs,and led to reduced crop nutrition levels,reduced soil fertility,water pollution,soil acidification and atmospheric damage.A series of environmental issues,such as how much nitrogen fertilizer can not only ensure the high and stable yield of corn,but also ensure the best quality of its grains,this is a scientific question worthy of study.In this study,in the two years of 2018 and 2019,two corn varieties of waxy corn Jinnuo 20(JN20)and Jindannuo 41(JDN41)were used as test materials.In the field environment,different nitrogen application treatments were set up.Effects of Agronomic Characters,Photosynthetic Characteristics,Yield,Nitrogen Metabolism and Kernel Nutrition Quality of Waxy Corn Plants.The main results are as follows:1.At flowering stage of waxy corn,within a certain range of nitrogen application,the plant height,stem diameter,and leaf area of?hree leaves of waxy corn increased with the increase of nitrogen application;SPAD value and net photosynthesis of three leaves of waxy corn cob during filling stage The rate gradually decreased after 15 days of pollination,and increasing the amount of nitrogen fertilizer application could increase the green time of the leaves to a certain extent,slowing down the rate of decrease of the net photosynthetic rate of the leaves;the increase of the amount of nitrogen application also caused the number of grains and The dry weight of 100 kernels increased significantly,and the spike length of JN20 gradually increased,but there was no significant change in bald tip length,while for JDN41,the bald tip length gradually decreased,and there was no significant change in spike length.In the end,the agronomic traits of JN20 reached the maximum under N2(240 kg·hm-2)treatment,while the plant height,stem thickness,and clover area of JDN41 reached the maximum under N3(360 kg·hm-2)Value,the rest of the traits are also the maximum under N2 treatment.2.Above-ground and root biomass and nitrogen accumulation of waxy corn during the grain filling stage gradually decreased with time,while grain biomass and nitrogen accumulation gradually increased.In a certain range of nitrogen application,the biomass of waxy corn increased with the increase of nitrogen application,and compared with low nitrogen treatment,increasing nitrogen application would reduce the nitrogen transfer from shoots and roots to the grain.Eventually,with the increase of nitrogen application rate,the yield of waxy corn also increased,and reached the maximum under N2(240 kg·hm-2)treatment.Increasing the amount of nitrogen fertilizer can significantly increase the activities of NR and GS in the grains of two waxy corn varieties JN20 and JDN41.3.During the period from 15 d to 35 d after pollination of two waxy maize varieties,the nitrogen harvest index,nitrogen transfer rate,contribution rate,nitrogen utilization efficiency,nitrogen fertilizer productivity and nitrogen agronomic utilization efficiency of the plant showed basic performance.There was a change trend that gradually increased with the advance of time;the nitrogen absorption efficiency gradually increased after 15 days of pollination,and reached a maximum at 30 days of pollination.Under different nitrogen treatments,nitrogen absorption efficiency,partial nitrogen productivity,and agronomic utilization efficiency of nitrogen fertilizer decreased with the increase of nitrogen fertilizer application during the filling stage of waxy corn.With the increase of nitrogen application rate,it decreased first and then increased;however,the nitrogen harvest index and nitrogen use efficiency only decreased with the increase of nitrogen application rate in the late filling stage.4.After 15 days of pollination of waxy corn,the contents of albumin,globulin,soluble sugar and lysine in the grain gradually decreased with time,and the contents of gliadin,gluten,total protein and nitrite will gradually decrease with time.Grains mature and gradually accumulate.And in a certain range of nitrogen application,the contents of albumin,gliadin,gluten,total protein,soluble sugar and lysine in the grain increased with the increase of nitrogen application,but no longer after excessive nitrogen application.There was a significant increase and even a certain decrease,and the nitrite content was significantly positively related to the amount of nitrogen fertilizer applied.5.The content of total starch,amylopectin and amylose increased with the gradual maturity of the waxy corn,and the ratio of amylopectin / total amylopectin remained within a relatively stable range.The total starch,amylopectin content and amylopectin / total starch ratio of waxy corn JN20 and JDN41 in a certain range of nitrogen application showed a gradual increase trend with the increase of nitrogen application,while the amylose content It decreases with the increase of nitrogen application.The activities of AGPase,SSS and SBE in the grain filling stage of waxy corn increased with time,showing a unimodal change curve that first increased and then decreased,and the activities of the three enzymes reached their peaks basically at 20 d after pollination;GBSS and DBE activities were at pollination 15 It gradually decreased during the period of 35 d.Within a certain range of nitrogen application,the activities of AGPase,SSS,SBE,and DBE in waxy corn kernels increased with the increase of nitrogen application,but excessive nitrogen application did not continue to significantly increase the activity of these enzymes;the opposite of them was GBSS activity,Which gradually decreased with the increase of nitrogen application.6.The anthocyanin content of JN20 grains gradually increased with the maturity of waxy corn during the grain filling stage,and the synthesis rate gradually decreased.And in a certain range of nitrogen application,the anthocyanin accumulation in grains increased with the increase of nitrogen application,and reached the maximum value under N2(240 kg·hm-2)treatment.The activities of PAL,F3 H and DFR in waxy corn JN20 grains were enhanced in the later stages of grain filling,while the activities of ANS and UFGT were decreased compared to those in the early stage of grain filling.Under different nitrogen treatments,the activities of PAL,DFR,and UFGT increased with the increase of nitrogen application in the early stage of filling,but showed the opposite effect in the late stage of filling;F3H activity was highest under the early N1(120 kg·hm-2)treatment.In the later period,it was the highest under N0(0 kg·hm-2)treatment. |
PDF Full Text Request