Effects Of Delayed Cultivation On The Sugar Accumulation And Related Enzyme Activities In Grape Fruits Under Water Regulation

In order to analyze the effects of water stress on the sugar accumulation and related enzyme activities in grape fruit at different growth stages,this experiment was carried out in 2017 in Yongdeng county of Lanzhou city,Gansu province.The"red earth"grape from 8A was used as the test material,and the grapes were divided into five growth stages,which were germination stage,new shoot growth period,flowering period,fruit expansion period and coloring maturity period,set up two levels of water stress in each growth period,which were mild water stress(60%of soil water content under field water capacity)and severe water stress(45%of soil water content under the soil water content limit),with adequate water supply in the whole stages(CK)as contrast,a total of 11 treatments.Mainly studied and analyzed the facility cultivation of grapes delayed growth characteristics,the change of the sucrose metabolism,the change of sugar accumulation and related enzyme activities at different stages under water stress,studied the influence of different water stress on grape yield and quality,in order to seek for the optimal water treatment,which not only less effect on grape growing,but also can improve the yield and quality,provide some theoretical basis for establishing reasonable irrigation system,high quality,high yield and water-saving for delay cultivation of grapes.The results show that:(1)The growth of new shoots of the cultivated grape showed the trend of"S",the length and coarseness of processing new tip growing up in new shoots grow fastest,the new tip length and roughness of GM treatment increased the fastest,3.67mm/d and0.19mm/d respectively,while the new tip length and roughness of PS treatment increased the slowest,2.70mm/d and 0.16mm/d respectively.The severe water stress in the new shoots can severely inhibit the growth of the new shoots,and the growth of the new shoots is most favorable for the mild water stress in the germination stage.Grape grain size growth present a"fast-slow-fast-slow""S"type of growth trend,10-26d and 75-91d after flowering,the grape grain size growth to the peak,Starting from 59d after the expansion period,ES processed the grape particle size less than other treatments,and severe water stress during the growth stage of fruit significa nt ly inhibited the growth of grape grain size.From the late stage of the fruit expansion,the light water stress in the coloring maturation stage is more favorable to the growth of grape grain size.(2)The facility delay the cultivation in the development process of the grapes,total sugar,glucose,fructose and sucrose content has been on the rise,but increased by fast slow,when the grapes ful y mature,reached the highest levels;Glucose and fructose are high in grape fruit,while sucrose content is very low.When grapes ful y mature,total sugar,glucose,fructose content of CM in fruit processing were higher than other treatment,which is 23.46%,12.7%and 10.8%,respectively,14.22%,20%,8.11%higher than CK treatment,FM processing sucrose content in fruits is higher than other processing,24.28%higher than that of CK treatment.The mild water stress in the maturation stage is beneficial to the accumulation of total sugar,glucose,fructose and sucrose in grape fruit at full maturity.The accumulation of glucose during the fruit enlargement period is not beneficial to the accumulation of glucose in grape ripening,and it can also severely inhibit the increase of fructose content in the fruit of the mature stage.Severe water stress in each growth period reduces the total sugar and glucose levels in the fruit.(3)When the grapes were ful y mature,ES and PS treatment were 27.9%and28.1%lower than CK respectively.Severe water stress in the growth stage of new shoots and the growth stage of fruits would affect the activity of sucrose synthase in the later fruits.At grape ripeness,SPS content in ES treated grapes was the lowest,29.2%lower than CK,and severe water stress during fruit enlargement would reduce SPS activity in later stage.At the end of fruit enlargement,the activity of AI in ES treatment was the lowest,significantly lower than CK treatment.The NI content is low in the fruit of ES on the whole growth period,fruit enlargement and coloring period of severe water stress inhibition AI and NI activity of fruit.SS is the key enzyme to regulate sucrose accumulation.SPS was negatively correlated with all kinds of sugar in fruit,but the correlation was not significant.AI is the key enzyme to regulate glucose.NI is the key enzyme that regulates fructose,glucose and total sugar.(4)Treatment of mild water stress during germination stage had the largest single grain weight and the highest yield,reaching 13.89g/grain and 49277.78kg/hm~2 in sequence,which was significantly higher than CK treatment.Water stress during the period of fruit swel ing will seriously reduce grape single grain weight and grape yield;When the grapes were ripe,PS was the highest concentration of titratable acid,which was 67%;the content of titratable acid in fruit was increased by severe water stress at different growth stages,and the titratable acid content was lowest in fruit with mild water stress at germination stage,and the taste of grape was sweet.In mature grapes,the soluble solids in CM were higher than other treatments,11.95%higher than CK;mild water stress during coloring maturity stage was the most favorable for the accumulation of soluble solids,while severe stress was not conducive to the improvement of soluble solids in the growth stage.The content of anthocyanin in mature fruit was highest in FM,which is 15.43 nmol/g;mild water stress is beneficia l to the improvement of anthocyanin content,especially in the germination stage and new shoots.