| With the global climate change, the increasingly frequent and severedrought appeared in some regions. In order to illustrate the regulation effect of thedifferent nitrogen supply and assimilation efficiency on drought resistance and yieldformation of wheat after flower, understand response patterns of different GSisoenzymes on drought after flowers and the relationship with nitrogen assimilationefficiency, a study taking wheat cultivar Zhoumai22as test material was conducted infield, with three irrigation treatments: normal irrigation (CK), restriction irrigation:only irrigation in jointing stage (J) and grouting stage (G), and three nitrogentreatments, no nitrogen (N0),120kg/hm2pure nitrogen (N1),240kg/hm2purenitrogen (N2). The results as follows:1. Compared with normal irrigation, leaf chlorophyll content and lower leaf netphotosynthetic rate, transpiration rate, stomatal conductance and leaf water useefficiency were reduced in restrictive irrigation, leaf intercellular CO2concentrationwas improved. In restrictive irrigation, compared with J, G increased the chlorophyllcontent of leaf, improved leaf net photosynthetic rate, transpiration rate, stomatalconductance and leaf water use efficiency, and decreased intercellular CO2concentration. Increasing nitrogen application can increase the chlorophyll content inleaves, increase leaf net photosynthetic rate, transpiration rate, stomatal conductanceand leaf water use efficiency, decrease intercellular CO2concentration; The aboveresults show that: Drought can reduce wheat photosynthetic ability. Under thecondition of insufficient irrigation, detaining irrigation period is helpful to improvewheat grouting photosynthetic ability. Increasing n application rate can improve the wheat leaf photosynthetic capacity, in the imperfect irrigation condition can beimproved by increasing nitrogen fertilizer area photosynthetic capacity.2. In the early grouting, there are no significant difference of wheat flag leaf watercontent in different treatments, relative water content have significant differences,which suggests that increasing irrigation can improve the storage capacity of wheatflag leaf. In the later grouting, water content and relative water content of normalwater treatment were significantly higher than restrictive irrigation treatments. Thedifferent maybe caused by the soil water capacity in this time. Compared with normalnitrogen, high nitrogen and no nitrogen are unfavorable to transshipment of nitrogenfrom leaf to grain under the condition of normal irrigation. Restrictive irrigation isbeneficial to nitrogen accumulation of wheat plant organs.3. In the grouting, GS enzyme activity gradually decreases with the grouting process,irrigation and increasing nitrogen application could improve GS enzyme activity ofwheat leaves. Expression of GS1and GS2genes all showed a trend that rise at earlyand fall at later, and expression of GS2gene faster fall in the late grouting, basicallyno longer GS2gene expression, while the expression of GS1gene was still in highlevel. Under the condition of low nitrogen can increase GS1in wheat flag leaf andGS2transcription level, under the condition of high nitrogen reduced the transcriptionlevel. Restrictive irrigation can improve GS1transcription; however, G was notconducive to GS2transcription.4. With nitrogen fertilizer increasing, wheat yield was increasing. Full irrigation wasbeneficial to the improvement of the wheat yield; irrigation period in advance canincrease the yield of wheat. On the three elements of wheat yield formation, theirrigation period in advance can improve the ear number per unit area; sufficient wateris conducive to the formation of the spike grain number, and not conducive to theincrease of grain. In the condition of fully irrigation, mu number of ears and grainsincreased with the nitrogen increasing. The effects of nitrogen on grain weight wereinconformity in different irrigation treatments, grain weight decreased with increasingnitrogen under normal irrigation, effect of nitrogen fertilizer is not obvious underrestricted irrigation. 5. Restricted irrigation can significantly increase water use efficiency of wheat,mainly because of the use of soil water increasing under insufficient irrigation.Increasing nitrogen application can enhance the carbon and nitrogen metabolism ofplant, increase plant dry matter, also can improve water use efficiency of wheatproduction. Compared with normal irrigation, nitrogen application increased couldincrease wheat nitrogen utilization under restrictive irrigation conditions. Undernormal irrigation, nitrogen application increased can improve the nitrogen utilizationrate. |
