Activities of enzymes directly related with sucrose and citric acid metabolism in citrus fruit in response to soil plastic film mulch.

Highlights: [•] Soil plastic film mulch (SPFM) increased sugar and acid accumulation in fruit juice sacs. [•] SS activities responded differently to SPFM in fruit segment membrane and juice sacs. [•] AI activity in fruit segment membrane responded positively to SPFM. [•] cyt-Aco and cyt-IDH activities in juice sacs were reduced by SPFM. [•] An enzymatic model for sugar and acid accumulation in citrus is presented. [Copyright &y& Elsevier]