Effects Of Different Light Conditions On Photosynthetic Abilities And Fruit Quality Of Strawberry

Strawberry(Fragaria × ananassa)fruits has rich nutritive value,while the production of highquality fruits is insufficient.Therefore,how to improve the fruit quality to meet the consumers' growing demands has become the urgent problem.Light conditions can influence plant photosynthetic abilities and fruit qualities.In order to produce high-quality strawberry fruits by regulating light conditions,“Akihime” cultivar seedlings were used to determine the photosynthetic characteristics and sugar content in leaves,the titratable acidity,sugar,soluble protein,anthocyanin,soluble solids,total phenol,vitamin C content and aroma emission of fruits under different light conditions.The results showed as below.1.Among different light quality treatments,red light showed the most positive effects on the strawberry growth,efficiency of PSII reaction center,photosynthetic pigment and sugar content in leaves.While yellow,green,blue and purple light showed different inhibitory effects.2.Red light can significantly improve the content of sugar,soluble protein and anthocyanin in strawberry fruit.While green and purple light had different degrees of inhibitory effects.3.The esters and terpenoids were the main types among the strawberry fruit aromas,and transnerolidol was the most typical component.Red light significantly promoted the emission of esters and trans-nerolidol by up-regulating the expression of the alcohol acyltransferase gene(FaAAT)and the nerolidol synthase 1 gene(FaNES1).While green and blue light showed the opposite effects.4.Both high and weak light can inhibit strawberry plant growth.The best growth status and highest pigment content in leaves were found under 75% light intensity(LI)treatment.The photosynthetic characteristics and sugar content of leaves decreased with decreasing light intensity,but there was no significant difference between 75% LI and 100% LI treatments.5.Except the sucrose,the sugar content in fruits decreased with decreasing light intensity,while there was no significant difference between 75% LI and 100% LI treatments.In addition,75% LI treatment can lower the titratable acidity,increase the sucrose content of fruits,and promote the emission of the esters and trans-nerolidol by up-regulating the expression of FaAAT and FaNES1.Comprehensive analysis,red light treatment and 75% LI treatment had obvious promotion effects on the strawberry growth,photosynthetic abilities and fruit quality.Therefore,these two light conditions should be applied to improve strawberry fruit quality in the facility cultivation during spring and summer in Zhejiang and its similar climatic province.