The distribution and species of Ca2 + and subcellular localization of Ca2 + and Ca2 +-ATPase in grape leaves of plants treated with fluoroglycofen

Abstract

Fluoroglycofen, a post-emergence herbicide used in vineyards to eradicate weeds, has previously been shown to turn grape leaves dark green following its use. Therefore, this study evaluates the relationship of dark green leaves with calcium form and subcellular distribution. To do this, we focused on the Ca2+ distribution and Ca2+-ATPase activity in leaf cells of one-year-old self-rooted Chardonnay grapevines treated with fluoroglycofen. Plants were separated into different treatments when they had seven or eight leaves, and different concentrations of fluoroglycofen were sprayed on the sand. The results showed that all of the soluble calcium content in the grape leaves that were treated with the highest concentration of fluoroglycofen (187.5gaiha−1) increased significantly. Specifically, the water-soluble organic acid calcium, pectate calcium, and calcium oxalate increased by 18.43%, 17.14%, and 31.05%, respectively, in the upper leaves than in the control. The subcellular distribution of Ca2+ in the dark green leaves increased significantly, especially in the cell wall and chloroplast, which increased by 25.54% and 24.10%, respectively. Through the ultrastructure localization of Ca2+ and Ca2+-ATPase contrasted with the control, the extracellular space and chloroplasts in the mesophyll cells of dark green leaves had large calcium pyroantimonate (Ca-PA) deposits. The extracellular space had fewer Ca2+-ATPase precipitation particles, whereas the chloroplasts had more. At the same time, a high concentration of fluoroglycofen decreased Ca2+-ATPase activity in grape leaves, which potentially might be due to disrupted regulation of calcium homeostatic mechanisms inside and outside of cells, resulting in a large number of Ca2+ accumulation in cells. The Ca2+ accumulation not only hindered the various cellular physiological reactions, but also caused leaves to become dark green in color.