Response of vegetative and reproductive organs of Cucurbita pepo L. Subsp pepo ‘Allegria’ exposed to aged dieldrin contamination in regards to soil concentration and plant development

Abstract

Abstract Aims Dieldrin is an Organochlorine Pesticides (OCPs) which, due to its persistence in agricultural soils, continues to be a source of contamination for crops, especially Cucurbita pepo L. subsp pepo (C. pepo L.). The latter are able to absorb dieldrin from contaminated soils and transfer it from the roots to the shoots. However, dieldrin allocation has been partially studied, especially in the shoots. This study aims at characterizing dieldrin distribution in the different plant organs according to soil contamination and plant growth. Methods This was achieved by growing C. pepo L. ‘Allegria’ in soil mixtures presenting 5 levels of dieldrin concentration (< 1 to 145 µg kg−1) and by harvesting them after different exposure periods (30, 90 and 140 d after transplant). Results The results showed (i) the predominance of the root impregnation path, (ii) that dieldrin concentration in the vegetative organs of C. pepo L. ‘Allegria’ increased with soil concentration while (iii) it stabilized for reproductive organs at soil concentrations exceeding 50 µg kg−1 DW. The bioconcentration factors (BCFs) for vegetative organs were classified as follows: stems (70) > roots (47) > leaves (19). Furthermore, the mass distribution of dieldrin was more dependent on variations in organ mass fraction with plant development than variations of dieldrin concentration in the different organs. Conclusions These results are of main importance for (i) the identification of dieldrin contaminated agricultural plots using phytoscreening methods as well as for (ii) their phytomanagement providing crucial allocation information for phytoextraction purposes.