Key factors affect selenite absorption in wheat leaf blades: pH, temperature, light intensity and leaf position

Abstract

Foliage-spraying selenite solution is an effective measure to enhance selenium (Se) concentration in wheat grains. However, how pH, temperature, light intensity, and leaf position affects selenite absorption in wheat leaf blades is not fully understood. In this study, the effects of pH, temperature, light intensity, and leaf position on selenite absorption in wheat leaf blades were investigated. The results indicated that the selenite absorption rate dramatically decreased with increasing pH. Further study revealed that aquaporin inhibitors such as HgCl2 and AgNO3 strongly inhibited selenite absorption at pH 3.0. Light and higher temperatures significantly promoted selenite absorption. Newly expanded leaf blades had higher rates of selenite absorption than younger and older leaf blades. Thus, higher rates of selenite absorption in leaf blades should attribute to the entrance of selenite into mesophyll cells via aquaporins in the form of H2SeO3 at low pH values. Foliage-spraying selenite solution on upper leaf blades at lower pH values benefited to increase the selenite absorption rate in wheat leaf blades.

Keywords

• se fortification
• foliar fertilisation
• selenium species
• environment factor
• efficiency of selenite absorption