Pesticides monitoring in intact plants by using non-destructive methodologies

PARLAKIDIS P.; FERNÁNDEZ CIRELLI A. ; IRIEL A. ; CORDON G.; BUSTOS N.; VRYZAS Z.

Foz do Iguazú

Congreso; 7º Congreso Latinoamericano sobre Residuos de Plaguicidas (LAPRW 2019); 2019

Latin Amarican Pesticide Residue Workshop

Introduction.Non-destructive methodologies for the monitoring of intact plant issues are typically based on measurements of reflectance and chlorophyll fluorescence. In environmental studies, the maximum quantum efficiency of the photosystem II (Fv/F0) and the quantum efficiency (PSII) are commonly used to evaluate the health status in plantsexposed to pollutants such as pesticides, heavy metals and others. Among the advantages of the use of these methodologies can be mentionedtheir lowcost, quick determinations and the possibility to evaluate big areas due to the possibility of applying them through satellite images.Dichlorvos (DDVP) and chlorpyrifos (CPF) are bothorganophosphorous pesticides mainly used in field, post-harvest treatments and animal production to control common pests that could be reach rural watercourses nearest. Objective.In this work, we explore the response of an aquatic plant, Hydrocotyle vulgaris, exposed to DDVP and CPF aqueous solutions in order to estimate which optical parameters are more sensitive to insecticide exposition.Methodology. Plantswere collected from a field located at Buenos Aires province and maintained in a nutritive Hoagland solution during a week in order to acclimate them. Then, plants were immersed in DDPV and CPF solutions (concentrations 0.1to 30 mg L-1) during 48 h. Kinetics chlorophyll emission was recorded by using a portable PAM-fluorometer (PAR-FluorPen FP 100-MAX-LM-D/BT, Photon Systems Instruments).Results were compared with control plants (without insecticide).Results and discussion.Obtained results indicateddeleterious effects in the status of exposed plants. Particularly, a strong diminution in the photochemical parameters of PSII and Fv/F0,evidenced that both insecticidesdrastically affected the photosynthetic apparatus functioning.In all the cases, the most affected parameter was Fv/F0 where a reduction of 4%, 29% and 68% was registered for solutions of CPF (standard), CPF (commercial) and DDPV (standard), respectively. In addition, PSII was reduced in 1%, 7% and 29% for CPF (standard), CPF (commercial) and DDPV (standard), respectively. Spite of the similarities, some differences were observed in the way that energy was delivered into the plant. In this sense, for CPF treatment, an increase in the emission chlorophyll was observed while for DDPV the thermal dissipation was enhanced regarding to the control plants. Conclusions.Photosyntheticparameters ofPSII and Fv/Fmhave resulteda sensitive tool to describe toxicological effects on aquatic plants exposed to insecticides. Moreover, chlorophyll fluorescence kineticmeasurements could represent a valuabletool to understand the mechanisms of insecticides on the photosynthetic process.