Tracking acetylcholinesterase inhibitor pesticides in the environment using the rapid transient of chlorophyll fluorescence.

Abstract

Several home pesticides are organophosphorus compounds. These compounds inhibit the enzyme acetylcholinesterase, causing harmful effects on the health of biota. Through this research, the usefulness of Glycine max (soybean) and Cichorium intybus (chicory) plants as sentinels of organophosphorus compounds in the environment was successfully tested. Different concentrations of the insecticide chlorpyrifos were tried out. Damage to plants at the photosynthetic apparatus level was evaluated by measuring the high temporal resolution variable chlorophyll fluorescence (OJIP test). Several parameters derived from this test indicated a high level of damage in both species even at the mean dose recommended for use in the field. However, a few parameters did not consistently reflect damage in leaves. A drop in the values of the maximum fluorescence (F_M), the quantum yield of electron transport flux, transport between quinones A and B (ET₀/ABS) and the maximal quantum yield of PSII (TR₀/ABS) could alert us about the presence of organophosphates in the environment. An increase in the dissipated energy flux per reaction center (DI₀/RC) values was also observed. The species showed different sensitivities, with soybean plants being the most sensitive. The OJIP transient thus becomes a valuable rapid, non-destructive tool for biomonitoring this class of pesticides in the environment.