| The aim of this paper was to know the effects of irrigation and nitrogen application regimes onprotective enzyme activity of the drip irrigation spring wheat and its yield. Through field investigationand fertilizing experiments, we analyzed the protection enzyme activity, content of MDA, NRA,Osmoregulation substances content during tillering stage, jointing stage, and filling stage as well astheir yield component. The experiment was conducted in the Xinjiang academy of agricultural andreclamation sciences, Shihezi Xinjiang Spring wheat (Xin chun6) was used as experimental material.Quadratic orthogonal design method was adopted, Among the two factors at three levels, the nitrogenlevels were: low nitrogen30(kg/666.7m~2), middle nitrogen40(kg/666.7m~2) and high nitrogen50(kg/666.7m~2); the water levels were: Serious dry300(m~3/666.7m~2), Middle dry400(m~3/666.7m~2)and Normal Water500(m~3/666.7m~2). District covers36m~2with250000basic seedlings per unit ofarea. The main experimental conclusions were summarized as follows:1. From jointing stage to filling stage, superoxide dismutase (SOD), peroxidase (POD), catalase(CAT) activity of drip spring wheat flag leaf took a trend of decreasing after rising, floweringprotective enzyme activity reaching the maximum, and malondialdehyde (MDA) content during thewhole growth period showed an upward trend. Appropriate irrigation and nitrogen application wouldresult in the increasing of SOD, POD, CAT activity and the decreasing of MDA of drip spring wheat.Under Seriously dry condition and low nitrogen condition, MDA content was higher. Reasonableirrigation and nitrogen application regimes had a certain regulation effect on the wheat, Neitherseriously dry condition nor low nitrogen was beneficial to wheat flag under the cell membrane stabilityof maintaining. Compared with nitrogen fertilizer, water was one of the most important factorsinfluencing the normal growth of wheat. Under normal water condition, protective enzyme activity ofwheat flag leaf increased with the increase of nitrogen. Under middle dry condition, nitrogen couldalso improve protective enzyme a little. Under seriously dry condition, protective enzyme activities ofthe flag leaf with middle nitrogen were significantly higher than those of low nitrogen and highnitrogen treatment, which indicated low water and low nitrogen treatment or low water and highnitrogen treatment had the most serious damage to the flag leaf. When water was deficient overnitrogen would increase water stress. On different nitrogen levels, protective enzyme activity of wheatflag leaf reduced with the water stress aggravating and MDA content increased. The nitrate reductaseactivity (NRA) was greatly influenced by nitrogen. Under the condition of normal water or middlewater stress, increasing nitrogen helped to improve the NRA of flag leaf. Under serious dry conditions,both low nitrogen and high nitrogen was unfavorable to the normal growth of wheat. Under differentnitrogen conditions, water stress caused NRA declining gradually.2. The results indicated chlorophyll, soluble sugar, proline and soluble protein content all showedincreasing trend with the water stress; Under severe drought conditions, over nitrogen applicationwould reduce the content of osmotic regulation material, influence the normal physiological function of wheat; Under moderate moisture conditions, the increase of nitrogen content showed a certainosmotic regulation ability; Under normal water supply conditions, increasing nitrogen makedosmoregulation content increased slowly.3. Under different water conditions, wheat plant height roughly present ascendant trend with theincreasing of nitrogen fertilizer, but the difference was not significant. However, under differentnitrogen levels, irrigation water had a little effect on wheat plant height. Under drip irrigationcondition, dry matter accumulation of wheat leaf showed ascendant trends during the whole growthperiod. Under a certain moisture conditions, the accumulation of dry matter improved obviously withthe increasing of nitrogen application. On different nitrogen levels, the dry matter of wheat leafdeclined gradually with the increasing of water stress.4. The results indicated the spike length, spike grain number and grain weight were the highest inhigh nitrogen treatment. The thousand seed weight of W2N2treatment was the highest42.96gram perthousand grain. Water and nitrogen management had significantly interaction effect on the control ofdrip irrigation spring wheat yield among which, W2N3treatment combination with the highest yieldof557.65kg/666.7m~2. |
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