| Grape(Vitis vinifera L.)has a high value in economy,nutrition and health care.Its yield and planting area are among the top fruits in the world.Nitrogen,as the most important element in the growth and development of grape,is a waste of resources due to the high annual application rate and low utilization rate.Therefore,it is of great significance to reduce the waste of resources by improving the absorption,transport and utilization of nitrogen in grapes.A large number of studies have shown that the internationally recognized endogenous plant hormone Brassinolide,which is highly effective,broad-spectrum and has no toxic side effects,can be used to regulate nitrogen uptake and transport in crops.Therefore,pot and field experiments were carried out at the same time to study the effects of spraying different concentrations(0,0.5,1.0,1.5 and 2.0mg/L)of 2,4-Epibrassinolide on its growth,fruit quality and nitrogen absorption characteristics,which in order to screen out the best concentration that can promote the growth and increase its fruit quality,nitrogen absorption and transport account of ’Summer Black’ grapes.This study is of great theoretical significance and practical value for high yield,high efficiency and high quality cultivation of grape and other fruits.The main findings are as follows:(1)The root biomass of ’Summer Black’ seedlings was the highest at 1.0 mg/L after spraying EBR,which was 55.68% higher than the control.whole plant biomass was the highest at 1.5 mg/L,which was 42.49% higher than the control.The content of chlorophyll a and b were the highest at 1.0 mg/L,which were 33.06% and 40.68% higher than the control.And the carotenoid content,Pn,Ci and Gs were the largest at 1.5 mg/L,which was16.56%,158.05%,39.77% and 50.00% higher than the control.After spraying EBR increased seedling biomass and photosynthetic pigment content,enhanced its photosynthesis,and promoted the growth of ’Summer Black’ grape seedlings.(2)After spraying EBR,the activities of catalase,peroxidase and superoxide dismutase in the leaves of ’Summer Black’ seedlings increased,and the contents of soluble protein and proline increased,which were the highest at 1.0 mg/L,and increased by123.26%,70.74%,52.73%,50.90% and 50.82%,respectively.malondialdehyde content decreased,and the treatment at 1.0 mg/L was the lowest,which was 43.75% lower than the control.After spraying EBR increased the osmotic regulatory substance content of’Summer Black’ grape seedlings and enhanced its resistance.(3)The content of soil organic matter and available nitrogen increased after spraying the EBR on ’Summer Black’ grape seedlings,and were the highest at 1.5 mg/L treatment,which increased by 34.91% and 8.22% compared with the control,respectively.The content of nitrate nitrogen in soil increased,but the content of ammonium nitrogen was opposite.Soil nitrate nitrogen was the highest at 2.0 mg/L,1.5 mg/L followed it,which was 42.43% and 23.00% higher than the control,respectively.All soil p H values were reduced,and the lowest value was at 1.5 mg/L,which was 2.60% lower than that of the control.After spraying EBR on ’Summer Black’ grape seedlings,the soil nitrogen content increased and its morphology was improved in favor of grape seedlings’ absorption and utilization.(4)After the application of EBR,the nitrogen content of roots,stems and whole plants of ’Summer Black’ seedlings increased first and then decreased,while the nitrogen content of shoots and leaves was opposite.When treated with 1.5 mg/L,the nitrogen content and nitrogen uptake of root,stem,leaf and whole plant were the highest,which were 52.68%,34.79%,5.65%,9.76%,22.84% and 132.10%,190.34%,36.57% and75.11% higher than control respectively.Roots,stems,and leaves nitrogen translocation,nitrogen transport efficiency,and nitrogen transport contribution rate all increased,all were highest at the treatment of 1.5 mg/L,which increased by 2.03,4.32,0.64 times,2.08,4.29,0.64 times and 0.32,0.84,and 0.19 times,respectively.The harvest index of root and stem nitrogen was higher than control,but the leaf was opposite.Spraying EBR increased the nitrogen absorption account and nitrogen transport efficiency of ’Summer Black’ grape seedlings.(5)After spraying EBR,the nitrogen content,nitrogen absorption,nitrogen transport volume,nitrogen transport efficiency and nitrogen transport contribution rate of the stems,leaves and fruits of ’Summer Black’ trees all increased,and all reached the highest at 1.5 mg/L,which increased by 1.75,1.29,0.41,0.40,1.98,1.98 and 1.12 times as compared with the control;1.0 mg / L treatment followed it,and increased by 1.51,0.59,0.09 times and 0.14,0.8,1.12 and 0.54 times,respectively.Spraying EBR increased the amount of nitrogen absorbed by the fruit tree,and improved the efficiency of nitrogen transfer of ’Summer Black’ grapes.(6)After spraying EBR,the contents of ’Summer Black’ fruit vertical and horizontal diameter,fruit weight,soluble solids,soluble sugar and vitamin C increased,the titratable acid content decreased,and the fruit hardness decreased only at 2.0 mg/L.The longitudinal diameter,weight and hardness of fruits were the highest at 1.5 mg/L.At 1.0mg/L,the contents of soluble solids and Vc in fruits were the highest,which increased by33.43% and 56.16%,respectively.At 1.5 mg/L,the soluble sugar content of fruits was the highest,which increased by 63.16% compared with the control.At 1.5 mg/L,the titratable acid content of fruit was the lowesst,which was 31.13% lower than that of the control.Spraying EBR improves the fruit quality of ’Summer Black’ grapes.As a result,spraying 1.5 mg/L EBR on ’Summer Black’ grapes leaves could improve the soil environment and nutrient content,promote photosynthesis and metabolism,improve nitrogen transport efficiency,improve its quality and commodity rate. |
PDF Full Text Request