Effect Of Soil Moisture Content On The Accumulation Of Phenolic Substances In 'Beihong' And 'Beimei' Grapevine At Maturity Stage

In this experiment,5-year-old wine grape 'Beihong' 'Beimei' was treated with different soil water content during ripening period,and the effects of soil relative water content on fruit quality and monomeric anthocyanin content of wine grape were studied.The effects of the accumulation of monomer phenol and the gene expression related to the synthesis of phenol were studied to explore the regulation mechanism of soil water content on the accumulation of phenol in grape fruit during ripening period.The optimum soil relative moisture content was selected to improve the fruit quality of wine grape.The results show that:1.The effect of soil relative water content on the fruit quality of 'Beihong' 'Beimei5 wine grape was significant,and too much water content could inhibit the formation of wine grape fruit quality at maturation period.Compared with CK?60%?70%?and other treatments,the contents of total phenol,tannin and anthocyanin in T3?50%?60%?treatment were increased,and the soluble solids and total sugar contents in T4?40%?50%?treatment were higher than those in T3?50%?60%?treatment.However,the accumulation of phenolic substances was significantly lower than that of T3?50%?60%?.2.Proper soil relative water content could significantly increase the content of anthocyanin in 'Beihong' 'Beimei' wine grape fruit,but the soil moisture content was too high or too low,it would inhibit the accumulation of monomer anthocyanin content.However,too low soil water content could significantly reduce the content of anthocyanin in 'Beimei' grape.Through HPLC detection of five anthocyanins,and it was found that the contents of cyanidin,delphinidin and malvidin in 'Beihong' grape T3?50%?60%?were relatively higher than those in CK?60%?70%?and other treatments.The contents of peonidin,delphinidinand malvidin in 'Beimei' grape treated with T3?50%?60%?were significantly higher than those of CK?60%?70%?and others.There was no significantly difference between cyanidin,petunidin and CK?60%?70%?,but T4?40%?50%?was lower than that of all treatment.3.Proper soil relative moisture content could increase the monomer phenol content of wine grape 'Beihong' 'Beimei'.By HPLC detection of 17 monomers,it was found that the contents of flavane-3-alcohols was high,which was the main components of the phenol substancesin the wine grape of 'Beihong' and 'Beimei'.The contents of phenolic acids,in flavane-3-alcohol and flavanones?naringin?were higher than those of CK?60%?70%?and other treatments under the treatment of T3?50%?60%?during the harvest period.However,the phenolic acid and flavonol content of "Beimei' grape treated with T3?50%?60%?were higher than that of CK?60%?70%?and other treatments.4.Proper soil relative water content could increase the gene expressions of PAL,CHS ando ther genes in wine grape.By sequencing the transcripts,it was found that during the synthesiso f phenol,CHS?VIT₀5s0136g00260??VIT₁4s0068g00920?,FLS?VIT₁8s0001g03430?,AOC3?VIT₀2s0025g04560?,PAL?VIT₁3s0019g04460?and CYP73A?VIT₀6s0004g08150?showed a higher expression level,The expression of CHS3?VIT₀5s0136g00260?was the highest,while the expression of F5H?VIT₀3s0038g00500?was lower.The results showed that soil relative moisture treatments had a great effect on grape fruit quality at ripening stage,and T3?50%-60%?treatment was available to improve the basic fruit quality indexes and it was also beneficial to the accumulation of anthocyanins and phenol.There fore,it was suggested that maintaining soil moisture content at 50%?60%during maturity was most beneficial to the formation of fruit quality of 'Beihong' 'Beimei' grape.