Effects Of Expanded Tube Row Ratio On Fructan Accumulation And Metabolic Enzyme Activity In Stem Of Spring Wheat After Drip Irrigation

【Object】Fructan is the main component of water-soluble carbohydrate(WSC),which mainly exists in wheat stalks.The level of fructan content directly reflects the ability of vegetative organs to store WSC.Fructan,as a signal molecule,can adapt to the environment by regulating its metabolism and enzyme activity under the stress condition,and can make up for the yield loss caused by the stress to some extent.In recent years,drip irrigation of wheat in Xinjiang has developed rapidly,but the input cost of "one pipe and four rows"(TR4)mode which is widely used now is high,and the advantages of drip irrigation are not fully exerted.Therefore,in the drip irrigation mode of "1 tube with 4 rows",two large row ratio drip irrigation modes of "1 tube with 6 rows"(TR6)and "1 tube with 8 rows"(TR8)were set in this study to explore the changes of dry matter and fructan accumulation and transport,yield and activities of key metabolic enzymes of fructan in stem of spring wheat after flowering after expanding row ratio of drip irrigation mode.To elucidate the influence of expanded line ratio on fructan accumulation and metabolic enzyme activity in stem of spring wheat,and to provide theoretical basis for selecting the optimal drip irrigation belt configuration mode.【Methods】Two spring wheat varieties,Xinchun 44 and Xinchun 22,which were different in sensitivity to water,were selected.The conventional drip irrigation mode with row ratio TR4 was taken as the control,and TR6 and TR8 were set as two large row ratio drip irrigation modes.The accumulation of dry matter and fructan in stem,transport,wheat yield and the activities of key metabolic enzymes of fructan were measured under three drip irrigation modes at different periods after flowering.【Results and conclusions】1.Under the three drip irrigation modes,the accumulation of matter in leaf and stem of wheat vegetative organs increased firstly and then decreased at different stages after anthesis.After expanding the tube row ratio,the dry weight per plant of wheat showed a downward trend,showing TR4 > TR6 > TR8,and the dry matter accumulation of water insensitive variety Xinchun 44 was always higher than that of Xinchun 22 at different stages after anthesis.Under the same drip irrigation mode,the farther the distance from the drip irrigation zone,the higher the fructan content in wheat row stems.The content and accumulation duration of fructan in Xinchun 44 increased and prolonged with the increase of the tube line ratio.The content of fructan in Xinchun 22 increased with the increase of line ratio,and the duration of fructan was shortened with the increase of line ratio,and the content of fructan in Xinchun 44 was significantly higher than that in Xinchun 22.Under TR4 and TR6 modes,the contribution rates of fructan to Xinchun 44 and Xinchun 22 in R1 row were 8.701% and 5.150%,respectively,and 7.971% and 7.466%,respectively.In TR8 mode,in R3 row of Xinchun 44 and Xinchun 22,the maximum contribution rates of Fuctan after flowering were 13.289% and 8.665%,respectively,which increased by 4.588% and 3.515%compared with TR4,and 5.831% and 1.199% compared with TR6 mode.The yield of Xinchun 44 and Xinchun 22 was the highest in TR4 mode,significantly higher than that in TR6 mode,and extremely significantly higher than that in TR8 mode.2.Under the three drip irrigation modes,the activities of fructose synthase;Sucrose1-fructosyltransferase(SST)in wheat stems increased at first and then decreased,and the decline rate of SST activity increased with the increase of line ratio.Under TR4 and TR6 modes,the SST enzyme activity of each wheat stem reached the highest at 10 d after anthesis.Under TR8 mode,the SST enzyme activity of wheat row R3 and R4,which were far from the drip irrigation zone,reached the peak at 15 d after anthesis,5 d later than that of the near row R1 and R2,and under the same drip irrigation mode,The decline rate of SST enzyme activity in culm of Xinchun 22 was higher than that of Xinchun 44.Under the TR4 and TR6 modes,the fructan synthase of Xinchun 22 in different wheat stems,fructan: The peak value of FFT activity in R3 and R4 rows was higher than that in R1 and R2 rows at 10 days after anthesis.Under TR8 mode,the SST activity of wheat in row R3 and row R4,which were far from the drip irrigation zone,reached the peak 15 d after flowering,and 5 d later than that in row R1 and R2.Moreover,under the same drip irrigation mode,the decline rate of SST activity in stem of Xinchun 22 was higher than that of Xinchun 44.The peak time of FEH activity in R2,R3 and R4 rows under TR8 mode was earlier than that in R1 row.In TR4 mode,Xinchun 22 showed a trend of first increase and then decline,while in TR6 mode,it showed a straight upward trend.In TR8 mode,the farther away from drip irrigation belt,the earlier the peak time of FEH enzyme appeared.In conclusion,after increasing the tube row ratio of drip irrigation,the peak time of SST and FFT enzyme activities was prolonged,the duration of fructan accumulation was prolonged,the fructan content was increased,the peak time of FEH enzyme activity was advanced,and the fructan degradation reaction occurred in advance,which promoted the transportation of fructan,and then increased the contribution rate of dry matter to grain after anthesis,and finally affected the yield.The contents,contribution rate and yield of fructan and dry matter in stem of Xinchun 44 were higher than those of Xinchun 22 when the tube row ratio was expanded.