Selenium uptake and fruit quality of pear (Pyrus communis L.) treated with foliar Se application

摘要

Consuming selenium (Se)-rich fruit may play an important role in human health by supplementing Se. The aims of this study were to (1) determine the Se tolerance of pear trees and (2) explore the effects of different Se sources and spraying dates on Se concentrations and transformation of inorganic Se into organic Se compounds in various parts of the pear tree and on fruit quality. Spraying Se(IV) or Se(VI) at a concentration of > 40 mg L-1 resulted in leaf yellowing, marginal withering, and finally leaf abscission. Furthermore, fruit growth and appearance were adversely affected at high Se doses. At the same application stage, Se concentrations in different parts of the fruit were 1.1-4.7 times higher under Se(VI) compared to Se(IV) treatment. For the same Se source, Se concentrations under treatment at the fruit expanding stage were 1.9-2.5 times higher than under treatment at the fruit-setting stage. Of the total Se in the fruit, 40% accumulated in the juice under Se(IV) treatment and > 70% under Se(VI) treatment. However, regardless of the Se source, the Se in the juice was almost all inorganic, while the transformation of inorganic Se into organic Se compounds was > 80% and 70% in the peel and pomace, respectively. Foliar Se application somewhat improved fruit quality by increasing the concentration of soluble solids. Compared to other species, Se tolerance in pear trees was relatively low. Given the high accumulation of Se and efficient transformation of inorganic Se into organic Se compounds in the peel, consumption of unpeeled Se-rich pears is recommended.