| The materials used in this trail were provided by academician Fu Tingdong.The four Varieties,6-16,6-27,6-45,6-51,were stable,but their water-logging tolerance varied. This test carried out in different growth stages and dealt with different level of ground water independently to study the effect and mechanism of rape in morphology,physiological Characters,yield.Compared with control(60cm water level),the higher underground water level(0cm) would have a negative impact,thus affecting the output of rapeseed;the difference of the reproductive growth and yield of rape between underground water level of 30cm-60cm and the control were not significant.On this basis, the 30cm water level was used as control,0cm water level treatment,the effect on the growth,yield and quality of rape caused by different duration of water-logging time were studied respectively in different growth stages,and to reduce the growth of rape and yield losses.The test was designed according the influence of different amount of N,P,K in increasing rape resistant to moisture.Under the conditions of different kinds of fertilizer ration in rape seedlings stages,comparison of the rape water-logging tolerance was made. By means of regression analysis on searching optimization,the fertilizer combination which improved the rape water-logging tolerance was filtered out to provide theoretical basis for increasing rape water-logging tolerance.The concrete researches show that:1 the influence of different underground water level on rape growing and yieldAfter dealing with different level of groundwater,all aboveground morphology indices of rape changed.Treatments,30-90 cm of water level,there was no significant change in shape of plants above the ground,and 0cm water level led to significantly lower shape of plants above the ground than the other water level.Seedling height reduced by 49.44%,51.92%reduction in the number of green leaves and leaf area decreased 31.34%,the ground dry weight reduction by 48.32%;bud stage height reduced by 39.37%,the ground dry weight reduction by 30.92%;reduce flowering plant height by 23.70%reduction on the dry weight of 26.28%.After dealing with different level of groundwater,the growth of rape underground root system was affected,root volume,root dry weight,root length had some changes.In seedling stage,plant of 90cm water lever,the root dry weight was heavier,root was longer,but the root indices of 0cm water level were significantly lower than that of control,0cm water level,root volume dropped by 42.31%,root dry weight dropped by 53.46%,22.64%decline in root length;in bud stage,60cm water level,root system grown better,the root growth of 0cm water level was the worst;in bud stage,0cm water level,root volume declined by 64.38%,root dry weight dropped by 60.00%,root length decline by 18.98%;in flowering stage 0cm water level,root volume fell by 50.29%,root dry weight dropped by 59.76%,16.60%decline in root length;in pod stages,0cm water level,root volume declined by 54.78%,root dry weight dropped by 54.14%,16.66% decline in root length.After dealing with different level of groundwater,the physiological index of rape changed.30-90cm water level,the relative content of chlorophyll,the photosynthetic rate, transpiration rate,stomatal conductance had no significant changes,but the indices described above of 0cm water level were significantly lower than others.In seedling stages,0cm water level,the relative content of chlorophyll declined by 33.94%,the photosynthetic rate fell by 28.51%,26.26%decline in transpiration rate,stomatal conductance decreased by 28.57%,and electric conductivity of 0cm and 90cm water level were significantly lower than control.,90cm underground water level decrease by 55.79%,while 0cm 63.54%.After dealing with different level of groundwater at bud stage,0cm and 90cm underground water level,the relative content of chlorophyll,the photosynthetic rate,transpiration rate,stomatal conductance were lower,0cm decreased most obviously,electrical conductivity was higher.The relative content of chlorophyll decline by 10.46%,27.12%decline in photosynthetic rate,transpiration rate fell by 13.71%,stomatal conductance decreased 17.46%,electrical conductivity increased by 47.17%,90cm electrical conductivity increased by 33.01%and was significantly higher than Control.After dealing with different level of groundwater,individual yield changed.0cm water level in seedling stage,individual yield decreased by 61.49%inmature period and was significantly lower than others.0cm and 90cm water level in bud stage,individual yield respectively decreased by 98.04%,25.33%and was lower than control.In flowering stage and pod sage,individual yield of 0cm water level respectively decreased by 88.63%, 62.72%.Thus,the underwater level should be controlled within 30-90cm in rape production,it would have its practical significance.2.The effect on the growth and yield of the rape under different duration of waterlogging time.Dealing with different duration of water-logging time,MDA content in the leaf of different growth period was higher than that of control;the content ofproline and soluble sugar increased,chlorophyll concentration decreased;this series of physiological changes led to the rape plant height,the number of green leaves,stem diameter,root volume decrease,but also reduce the accumulation of dry matter such as root dry weight,heavy stems and leaf dry weight.After water-logging in rape seedling,the number of single pod reduced from recovery growth to harvest,thus individual yield declined.Water-logging for 10d,20d, 30d yield of rape decreased by 6.0%,15.0%-20.0%,18.0%-30.0%,respectively.inthe same time,the analysis of quality showed that,after water-logging,compared with control protein of rapeseed was improved to a certain degree,and with the extension of water-logging increasing,the rate increased.Water-logging for 10d,20d,30d,protein, sulfuric glucoside increased by 1.0-6.0%,4.0-7.0%,5.0-9.0%,9.0-17.0%,12.0%,10-25%, separately.While oil content decreased with the extension of water-logging,and the longer water-logging time was,the larger range that increased,water-logging for 10d,20d,30d,it declined by0-7%,1-10%,1-14%,respectively.In bud stage and the flowering period,rape was sensitive to moisture.After water-logging in the two stages,effective pod number per plant,seed number per pod, 1000-grain weight all decreased obviously,yield per plant declined finally.The longer the water-logging time was,the more it lost.Bud stage water-logging for 10d led to yield reduce by 49.0%-90.0%,20d caused the yield of water-logging material dropped by 77.0 %,not water-logging material varieties was completely loss in harvest;flowering period water-logging for 10d,15d,20d,yield decreased by 45.0%-80.0%,48.0%-97.0%, 85.0%-97.0%.Water-logging in pod stage led to the decline in pod number and 1000-grain weight,thus yield significantly decreased.Water-logging for 10d,15d,yield dropped by 14.0%-18.0%,25.0%-27.0%.Yield per plant in pod stages reduced by 28.0%-33.0%.3.different fertilizer application rates,the influence of water-logging on rape growth Under normal conditions,phosphate combined with nitrogen fertilizer,no application of nitrogen fertilizer,or a lower level of nitrogen,phosphate fertilizer had no significant effects,on the contrary,it had negative effects;application of nitrogen in the high-level(level 3-5),phosphate fertilizer efficiency was clearly demonstrated.In the same time high nitrogen(4-5 level),with reasonable phosphate fertilizer,could reduce the adverse impact on root system and promote the absorption of nutrients and water,enhance moisture resistance.To improve moisture resistance of rape under water-logging conditions,a higher level of nitrogen with higher levels of phosphate fertilizer combination was conducive to rape increased stain-resistant in seedlings stage.In the pot experiment,each pot with 3kg,nitrogen fertilization requiredl.80-2.4Og,phosphate fertilizer 2.76-5.52g,potassium 0.64-1.29g,can better improve the stain-resistant of rape in seedlings.
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