Role of Foliar Biointerface Properties and Nanomaterial Chemistry in Controlling Cu Transfer into Wild-Type and Mutant Arabidopsis thaliana Leaf Tissue

SevenArabidopsis thalianamutants with differences in cuticle thickness and stomatal density were foliar exposed to50 mg L-1Cu3(PO4)2nanosheets (NS), CuO NS, CuO nanoparticles, and CuSO4. Three separate fractions of Cu (surface-attached,cuticle, interior leaf) were isolated from the leaf at 0.25, 2, 4, and 8 h. Cu transfer from the surface through the cuticle and into theleaf varied with mutant and particle type. The Cu content on the surface decreased significantly over 8 h but increased in the cuticle.Cu derived from the ionic form had the greatest cuticle concentration, suggesting greater difficulty in moving across this barrier andinto the leaf. Leaf Cu in the increased-stomatal mutants was 8.5-44.9% greater than the decreased stomatal mutants, and abscisicacid to close the stomata decreased Cu in the leaf. This demonstrates the importance of nanomaterial entry through the stomata andenables the optimization of materials for nanoenabled agriculture.

Automated summary

This study investigated the absorption of Cu nanomaterials by different Arabidopsis thaliana mutants, revealing variations in the transfer and accumulation of Cu in different plant parts. The stomatal density and cuticle thickness of mutants were found to affect the absorption of Cu.