Effects Of Fruit Development Period And Post-harvest Treatment On Aromatic Substances And AAT Activity In Strawberry

In this study was carried out in the greenhouse of Shandong Agricultural University,'Fragaria×ananassa Duch. cv Toyonoka'and'Fragaria×ananassa Duch.cv. Rosa'were used to study the changes of aroma components and their relative content by using GC-MS, at the same time, alcohol acyltransferase (AAT) activity was determined with the method of DTNB colorimetry. To study the changes of aroma components,their relative content and the activity of AAT in different development periods in strawberry. And study the changes of aroma components,their relative content and the activity of AAT under ethephon and STS treatments. The main results are as follows:1.'Toyonoka' and 'Rosa' were not detected esters in green stage, in white,pink and red stage the content of esters in 'Toyonoka' fruit were 4.9%. 8.86% and 32.18%, 'Rosa' fruit were 0.23%. 14.65% and 23.25%. The relative content of alcohol in 'Toyonoka' fruit development process were 28.52%,44.36%. 54.35% and 5.17%, 'Rosa' were 51.28%,68.2%. 4.05% and 2.27%.2.In green stage 'Toyonoka' and 'Rosa' was not detected the activity of AAT and the content of esters.In other development period the activity of AAT in 'Toyonoka'was significantly higher than that 'Rosa'.In white, pink and red stage the activity of AAT in 'Toyonoka' fruit were 2.5, 10.4 and 12.5 mU·mg-1protein, 'Rosa' were 0.8, 6.3 and 7.9 mU·mg^-1protein. The activity of AAT in two varieties of fruit were gradually increased with their ripening.The relative content of esters were increased with the activity of AAT enhance.3.'Rosa'strawberry fruit was treated by ethephon in white stage.With the increased concentration of ethephon, the relative content of esters in fruit showed an increasing trend.Under low, middle and high ethephon,the relative content of esters are 3.04%. 6.64% and 5.83%,which were increased by 12.2 times, 27.9 times and 24.3 times respectively, compared with controls (0.23%). ethephon can promote synthesis of esters in fruit.And the middle concentration(500mgL^-1) was the most significant.Ethephon inhibitor,silver thiosulfate (STS),can significantly inhibited esters synthesis. The relative content of esters in fruit was 0 in white stage treated by 1mmolL^-1STS,which was significantly lower than CK(0.23%).Ethephon and STS can affect other aromatic substances.But the regularity characters were not obviously.4.'Rosa'strawberry fruit was treated by ethephon in white stage.With the increased concentration of ethephon, the activity of AAT in fruit was significantly enhanced.The activity of AAT were1.5,2.7,3.0 mU·mg^-1protein under light,middle and high concentration,which were obviously higher than CK(0.8 mU·mg^-1protein).The activity of AAT in strawberry fruit was 0 mU·mg^-1protein under STS.Thus STS can inhibit the activity of AAT in fruit.