| The experiment was carried out under the automatic control canopy at the Henan Agricultural University Science and Education Park Area in 2008-2009. We systematically studied the effects of drought and rewatering on growth, photosynthetic characteristics, protective enzyme system, lipid peroxidation product, osmoregulatory molecules, filling rate, yield and water use efficiency of winter wheat under different conditions of growth and fertility. The main conclusions were as follows:1, Effect of drought and rewatering on growth of winter wheat under different fertility conditionsOn the whole, green returned stage adapted to drought stress was stronger than jointing stage, the effect of serious drought stress was stronger than moderate drought stress. Plant height, dry matter accumulation quantity of root and shoot of winter wheat exceeded its corresponding drought contrast after rewatering, presented compensatory or ultra compensatory effect, the compensation effect of drought at green returned stage was stronger than jointing stage; moderate drought stress was stronger than serious drought stress; high fertility>medium>low. The photosynthate allocated to increase the proportion of shoot after rewatering, and maked root-shoot radio decrease.2, Effect of drought and rewatering on chlorophyll content and Photosynthetic rate of winter wheat under different conditions of fertilityChlorophyll content and Photosynthetic rate of winter wheat decreased with the serious of drought levels under the same fertility condition, and decreased with the reduction of fertilizer levels under the same water condition whether drought stress treatment at green returned stage or jointing stage. Chlorophyll content and Photosynthetic rate of winter wheat exceeded its corresponding drought contrast after rewatering, presented compensatory or ultra compensatory effect, photosynthetic rate of post-anthesis was no significant difference between drought stress treatment at green returned stage and its corresponding wet comparison, even more than the corresponding wet comparison; and no significant difference between drought stress treatment at jointing stage and its corresponding wet comparison before maximum, then significant difference after maximum, it was not conducive to grain filling at late stage.3, Effect of drought and rewatering on SOD and MDA of winter wheat under different fertility conditionsSOD activity and MDA content of winter wheat increased with the serious of drought levels under the same fertility condition, but at the low fertility condition, SOD activity was moderate drought stress comparison > serious drought stress comparison > wet comparison; SOD activity and MDA content of winter wheat reached or nearly its wet comparison levels except of MDA content of serious drought stress at jointing stage after rewatering 20 days, presented compensatory or ultra compensatory effect; SOD activity decreased with the reduction of fertilizer levels under the same water condition; MDA content increased with the reduction of fertilizer under the moderate drought stress; medium fertility >high > low under the serious drought stress.4, Effect of drought and rewatering on osmotic adjustment of winter wheat under different fertility conditionsProline and soluble sugar content of winter wheat increased and soluble protein content decreased with the serious of drought levels under the same fertility condition, and increased with the reduction of fertilizer levels under the same water condition. After rewatering 20 days,proline,soluble sugar and soluble protein content of winter wheat reached or nearly its wet comparison levels except of soluble protein content content at jointing stage and green returned stage under medium and low fertility condition. proline,soluble sugar and soluble protein content increased with the increase of soil fertility under the same water condition.5, Effect of drought and rewatering on filling rate of winter wheat under different fertility conditionsFilling rate of winter wheat increased before reaching maximum and decreased after the maximum with the serious of drought levels under the same fertility condition, moderate drought stress comparison under low fertility condition and serious drought stress comparison reached maximum after 20 days after flowering, and the other treatments reached maximum after 25 days after flowering. Filling rate of drought stress treatments at green returned stage the decrease in the late filling stage was lower than the corresponding wet comparison,which presented ultra compensatory effect, filling rate was not significant difference between drought stress treatments at jointing stage and its corresponding wet comparison before maximum, then significant difference after maximum, it was not conducive to increase yield.6, Effect of drought and rewatering on grain yield and WUE of winter wheat under different fertility conditionsBiological yield, grain yield, the effective numbers of ears, the grain numbers of each ear and the 1000 grain weight of winter wheat decreased with the serious of drought levels under the same fertility condition. Biological yield was significant difference between drought stress treatments at green returned stage and its corresponding wet comparison, grain yield and three components of yield were not significant difference, and significant difference between drought stress treatments at jointing stage and its corresponding wet comparison. They were significant difference with the reduction of fertilizer levels under the same water condition.Moderate drought stress comparison of water use efficiency (WUE) under the high fertility condition was the highest, and no significant difference with serious drought stress comparison and drought stress treatments at green returned stage, serious drought stress comparison of WUE was high under the medium and low fertility condition, and no significant difference with other treatments. WUE decreased with the reduction of fertilizer levels under the same water condition. The results suggested that properly increasing fertilizer amount is conducive to recovery and increase water use efficiency of winter wheat. |
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