A Preliminary Study On The Effect Of Light Intensity On The Dynamic Changes Of Anthocyanin Content In Blueberry

Anthocyanins are the main health components in blueberry fruits,which have strong antioxidant and free radical scavenging ability.In addition to the variety difference,the composition and content of the fruit are also affected by environmental factors such as light.However,the dynamic changes of anthocyanin content in blueberry fruits and leaves,as well as the correlation between related physiological indicators and light are not clear at present.Therefore,in this study,Southern Highbush Blueberry Cultivars under High Tunnels"O'Neill"was used as the research material,researching and analyzing the anthocyanin content in blueberry fruits and leaves at white,purple and blue fruit stages under different light intensity by using a photometer,set four light intensities,take full light as a contrast and 75%light intensity,50%light intensity,25%light intensity respectively.At the same time,the levels of anthocyanin synthesis parameters such as endogenous hormone content and enzyme activity in anthocyanin synthesis pathway under different light intensity were compared and analyzed.The research conclusions are as follows:1.At three developmental stages,light intensity significantly affected anthocyanin content in blueberry fruits and leaves.The content of anthocyanin in blueberry fruits increased with the increase of light intensity,and the content of anthocyanin in CK was the highest.Under the same light intensity,the content of anthocyanin increased gradually with fruit development,and reached the highest value in the blue fruit stage.In each period,the content of anthocyanin in blueberry leaves increased first and then decreased with the increase of light intensity,and the content of anthocyanin in leaves was the highest under 75%light intensity.With the development of fruit,under the same light intensity,the content of anthocyanin in blueberry leaves showed a trend of decreasing first and then increasing at different development stages,and the content was the highest at blue fruit stage.2.Light intensity has an important effect on the photosynthetic characteristics,chlorophyll content,endogenous hormone content,sugar content,and anthocyanin biosynthesis related enzyme activities of blueberry.Under low light,photosynthetic parameters such as maximum net photosynthetic rate(Pmax),photosynthetic rate(Pn)and stomatal conductance of blueberry leaves were significantly decreased,but chlorophyll content was increased.Insufficient light reduced the contents of soluble sugar and reducing sugar in blueberry fruits and leaves.The contents of indole acetic acid(IAA)and gibberellin 3(GA₃)increased,while the contents of ethylene(ETH)and jasmonic acid(JA)decreased with the increase of light intensity.Abscisic acid(ABA)content in white stage and purple fruit stage increased first and then decreased,while ABA content in blue fruit stage decreased and then increased.The content of ABA in leaves decreased at white stage and purple fruit stage,but increased at blue fruit stage and then decreased.In the same development period,the activities of phenylalanine ammonia-lyase(PAL),chalcone isomerase(CHI),dihydroflavonol reductase(DFR)and flavonoid glycotransferase(UFGT)in blueberry fruits and leaves in response to light intensity showed that the activities of enzymes increased with the increase of light intensity.The activities of PAL,CHI,DFR and UFGT in leaves and fruits were increased from white stage to blue fruit stage under the same light intensity at different development stages.3.In different developmental stages of blueberry fruit,the regulatory factors of anthocyanin content in blueberry fruits and leaves affected by light intensity were different.The correlation and principal component analysis showed that the main regulatory factors affecting the content of anthocyanins in blueberry fruits at white stage were fruit hormones,which positively promoted the contents of JA,soluble sugar and CHI in fruits and inhibited the contents of IAA and ABA in fruits.In leaves,enzyme activities and hormones are the main components,which are realized through positive regulation of JA,ETH content and CHI activity in leaves and negative regulation of GA₃,IAA and ABA content in leaves.During the purple fruit stage,the light intensity regulated the content of anthocyanins in fruits mainly by enzyme activity and hormone activity,which was the joint result of positive promotion of CHI activity,Pn and PAL activity in leaves and inhibition of GA₃,IAA and chlorophyll A content in fruits.The contents of JA,ETH and ETH in fruits have A positive regulation effect on the hormone,while the contents of ABA,chlorophyll A and chlorophyll B in leaves have A negative regulation effect on the hormone.In the blue fruit stage,the regulation of anthocyanin content in fruits by light intensity was mainly based on fruit hormone and enzyme activities,and the common result was that the contents of IAA,Pn and soluble sugar in leaves were positively promoted and the contents of IAA,GA₃ and GA₃ in fruits were inhibited.Anthocyanin content in leaves was mainly regulated by enzyme activity,hormone and total chlorophyll in fruits,and was positively regulated by ETH content,DFR activity and PAL activity in leaves,and negatively regulated by chlorophyll A,chlorophyll B and total chlorophyll content.