The Study Of Growth, Physiology, Yield And Quality Of The Wheat Responses To Increasing CO₂ Concentration In Different Nitrogen Level

This study mainly investigated the wheat's growth,physiological characteristics and the quality.And use the open-top chamber control to the increased CO₂ concentration,set up two nitrogen level of treatment for the wheat's height,leaf area,net photosynthetic rate, transpiration rate,water use efficiency,stomata conductance,yield and yield components, chlorophyll content,mineral elements and the content of the amino acid.And compare the high level nitrogen's influence to the wheat's growth,physiological characteristics and the quality of with the low level nitrogen.The results showed that compare to 350μmol·mol^-1,when the content of the CO₂ 550μmol·mol^-1 and 750μmol·mol^-1,the height of the wheat increased by 5.6cm and 11.7cm,the high level content of the nitrogen treatment also showed the rising trend,and compare to the low level nitrogen the height of the wheat has increased by 0.65cm-2.45cm.when the wheat almost finished the vegetative growth,the area of the leaves were increased very fast.compare to 350μmol·mol^-1,the average increase of the area of the leaves were 7.33%and 27.48%. and compare to the low level nitrogen the high level nitrogen the increase level was 0.97%.when the wheat get into the reproductive growth,the area of the leaves were in the aging yellow period and compare to 350μmol·mol^-1,the area of the leaves under the two high level CO₂treatment were reducing.The increase of the CO₂ promotion the wheat's net photosynthesis,water use efficiency and of the increase,Blowhole leading.But the transpiration rate was reduced.Compare to the CK,the net photosynthesis had different change under the two high level CO₂ treatment.The biggest result was at the jointing stage:21.5%and 39.0%,the following was filling stage:18.2%and 32.0%,the smallest was at flowering stage:11.2%and 19.4%.through the study,compare to the low level nitrogen the net photosynthetic rate the high level nitrogen were increased by 3.36%,2.85%,3.9%at the jointing stage, 2.25%,1.86%,3.13%at the heading stage,1.76%,1.41%,1.40%at the flowering period, 0.76%,3.5%,2.76%at the filling stage.This showed that increase the concentration of the CO₂ would speed up the net photosynthetic rate,and can accumulated more photosynthetic material,increased the height of the wheat,increased the production at the same time.When the content of the CO₂ increased the wheat's net photosynthetic rate,the water use efficiency were all increased,but transpiration and the blowhole leading were reduced. Compare to the CK the net photosynthetic rate increased by 2.02%,16.68%,the water use efficiency increased by 9.84%,24.16%.but the transpiration reduced by 7.33%, 15.01%,the blowhole leading reduced by 14.09,24.29%under the low level nitrogen.And the net photosynthetic rate increased by 2.59%,18.96%,the water use efficiency increased by 9.84%,24.16%.but the transpiration reduced by 7.33%,15.01%,the blowhole leading reduced by 10.92%,21.97%under the high level nitrogen treatment.The wheat's day change of the net photosynthetic rate had the lunch break in photosynthesis under the low level CO₂ treatment.When the CO₂ concentration get to 750μmol·mol^-1 the change disappear.The change trend of the day net photosynthetic rate was the bimodal curve under the low level nitrogen.But the change trend of the high level nitrogen was a single peak curve.During the two level nitrogen treatment,when the content of the CO₂ increase, chlorophyll a,chlorophyll b,and the total chlorophyll were all increased.compare to the CK chlorophyll a increased by 11%and 14.8%under the two high level CO₂ treatment, Chlorophyll b increased by 12.9%.and 18.2%,Total chlorophyll increased by 11.5 and 15.7%under the low nitrogen level.The high level nitrogen treatment,compare to the CK chlorophyll a increased by 11.1%and 16.7%,Chlorophyll b increased by 10.9%and 19.5%,Total chlorophyll increased by 11%and 17%.Compare to the low level nitrogen treatment,chlorophyll a,chlorophyll b,total chlorophyll increased 4.31%,6.49% and 4.89%when the CO₂ in 350μmol·mol^-1,4.32%,4.60%and 4.39%in 550μmol·mol^-1,5.42%,7.69%and 6.04%in 750μmol·mol^-1.The production of per plant would be improved as the increased CO₂ content.The production had increased by 8.80%and 18.51%under the two high level CO₂treatment compare to the CK.And the production increased as the nitrogen content increased.The CO₂ increased,the production was increased,and the most notable is the small ears of each ear increased grain weight Secondly,the smallest number of grain.When the content of the CO₂ increased,the phosphorus,potassium,iron,copper, molybdenum and sodium content of the lower trend,phosphorus,iron,potassium elements in larger decline.Compare to the CK,the phosphorus content reduced by 8.9% and 11.8%,iron content reduced by 7.5%and 10.8%.potassium content reduced by 2.5% and 7.7%.copper,sodium,molybdenum in a relatively small decline in the rate,Calcium elements had no significant change.And on the other hand the magnesium,zinc, manganese,selenium,iodine content in a growth trend.zinc increased by 11.3%and 34.4%,Se increased by 11.1%and 44.4%.Magnesium increased by 10.6%and 13.6%, manganese and iodine increased by 7.0%to 8.8%.So it can be included that some part of the elements content such as phosphorus,iron and so on would be reduced by the high level CO₂,and it would reduced the quality of the wheat.But zinc,selenium,iodine and other elements were increased,and it can be increased the quality of the wheat.The content of the elements increased as the nitrogen increased.The wheat protein content and changes were not follow the CO₂ change.The increased CO₂ changed the amino acids and amino acid composition.Asp,glutamate,Gly, Hom,Val,Iso,Leu,Try,Arg were all reduced as the CO₂ increased.The biggest change is Gly,reduced by 23.18%,40.58%and 27%,43.2%,then the Hom reduced by 13.8%,17.9% and 9.7%,30.2%.Thr and Ser didn't have change.Ala,Met,Tyr,Lys,Phe,His were all increased to the CO₂ content.During the two nitrogen level treatment,compare to the CK the essential amino acids was reduced by 1.73%,15.61%and 5.07,17.0%.And compare to the low level nitrogen,the total amimo acids was increased.The essential amino acids and amino acids with the ratio of total was increased by CO₂.