| Shiyang River Basin is one of three continental river basins in the Hexi Corridor in Gansuprovince in China, the limited water resources in the basin carries too much population andeconomic activity, and resulting in a serious shortage of water resources. Wine grape industryis a key industry of the Shiyang River Basin and the whole region of the Hexi Corridor. As atypical inland arid region, the contradiction between water scarcity, soil salinization andunreasonable irrigation, fertilization management had seriously hampered the healthydevelopment of the grape industry.This study use wine grapes Merlot as the research object. Wine grapes sap flow wasobserved in2010-2012under the different water and nitrogen conditions, and thought themeasured of leaf area, berry diameter, chlorophyll content, soluble solid, yield and leafphysical signs, we studied wine grape transpiration mechanism, physiological feature andregularity of dry matter accumulation under different moisture, nitrogen condition in desertoasis. And base on it, we studied water-carbon model under different nitrogen condition. Thespecific research results are as follows:Wine grapes on different moisture and nitrogen conditions showed different responsecharacteristics, the increased amount of nitrogen will promote the growth of the plant leaf areaand chlorophyll content, but it will reduce the crop root growth. And limited moisture deficitwill make grape fine root growth to the soil depth direction; under the traditional irrigationmethod, nitrogen can increase the yield of vine grape, and decrease water consumption, butnitrogen will reduce soluble solid content of wine grape. water deficit could decrease the yieldof wine grape, meanwhile it can also increase soluble solid content of grape berry, on the otherhand, small tube flow irrigation can increase the soluble solid content under high nitrogensupply.Vinetree sap flow was mainly controlled by the leaf area indexat initial growth stage,while by radiation, air temperature and humidity and soil moisture at the mid and latergrowthstage. But the response patterns of vine-tree sap flow to these environmental factors werenotably differentunder different weather conditions. The agreement between sap flow and such meteorological factors, such asradiation, air temperature and humidity in the cloudy days wassignificantly higher than that in the clear days, while the agreement between sap flow and soilmoisture in cloudy days was notably lower than that clear days. Inaddition, the sap flow waspredominantly affected by radiation in clear days, while by air humidity in the cloudydays.At the whole growing season, diurnal variations of vine grape sap flow all shows assignificant unimodal or bimodal curves. The daily sap flow values of the vine grape showedobvious seasonal variations in the whole growth season. There are lower sap flow velocityatearlier and latter stages of growth season, and higher sap flow velocity at the middle stage.Enhance nitrogen supply appropriatecan increase sap flow velocity, but Excessive nitrogenapplication can result salt stresson plants and reduce the sap flow velocity of vine grape. Forinstance, in2011, the unit cross-sectional area stems sap flow accumulation of highnitrogen(HN), middle nitrogen(MN) and low nitrogen(LN) supply are20.30,30.94and34.70L/cm~2, respectively, and the values of middle nitrogen(MN) and low nitrogen(LN)supply are1.52and1.71times of high nitrogen.Soil moisture deficit will lead to the reduction of photosynthetic rate, but moderate waterdeficit will improve leaf water use efficiency of wine grape. In the fruit growth stage, waterdeficit reduced under high nitrogen condition limitedly the photosynthetic rate, but water useefficiency increased by1.7%, while in fruit growth medium stage, photosynthetic rate was notonly a slight increase with the soil moisture content at55%θf, but water use efficiency reachedat1.70μmol·CO2·(mmol·H2O)-1, higher than the other treatments. Based on the photosynthesisrate, stomatal conductance, transpiration rate and leaf water use efficiency of the curve ofresponse to light intensity can be seen, the nitrogen regulated transpiration rate by controllingthe degree of stomatal opening, and improved the physiological characteristics of plants toincrease the plant maximum net photosynthetic rate, apparent quantum efficiency and otherphotosynthetic indicators, so as to achieve the purpose to improve water use efficiency.MAESTRA model simulated transpiration rate and net assimilation rate of wine grapes inthe North west Arid Area of different nitrogen conditions then found that it would get differentmodel parameters of the wine grape parameterized under different nitrogen conditions, and theenhanced nitrogen changed the plant leaf area, photosynthetic and stomatal behavior. In thesimulation process of the model, considering the impact of nitrogen on the model couldimprove the accuracy of the model; using different physiological parameters during the wholegrowth period of the wine grape different times could also improve the model accuracy. Thenet photosynthetic rate of the whole growth period under different nitrogen conditions was notmuch difference at a nearly stage, while because of the impact of nitrogen on plantphysiological indicators and physical indicators, the net photosynthetic rate of HN was gradually higher than other treatments until the end of the growth period. Increasing nitrogensupply also affected the amount dry weight accumulation. |
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