International Letters of Natural Sciences Vol. 84

Abstract: Imidacloprid is a widely used pesticide that belongs to the class of neonicotinoids. There is a piece of rising evidence that neonicotinoids exert cytotoxic effects in non-target organisms including vertebrate species such as mammals. Nevertheless, dose-limiting toxicity and molecular mechanisms of neonicotinoids' deleterious effects are still poorly understood. In accord to imidacloprid fate in the environment, the most of used pesticide is absorbed in the soil. Therefore, earthworms, which are prevailing soil organisms, could be considered as a target of neonicotinoids toxicity. The earthworm’s simple nervous system is a prospective model for neurotoxicological studies. We exposed earthworms to imidacloprid in a paper contact test with a doses range of 0.1‑0.4 µg/cm² for 14 days. In the present work, we studied the imidacloprid effect on oxidative stress generation and neuronal marker neuron-specific enolase (NSE) expression. The exposure to imidacloprid induced a dose-dependent decrease in NSE. Both reactive oxygen species production and lipid peroxidation level were upregulated as well. Observed NSE decline suggests imidacloprid-caused disturbance in earthworm neuron cells. Obtained data have shown that relatively low doses of imidacloprid are potent to induce cytotoxicity in neurons. Furthermore, neurotoxicity could be recognized as one of an individual scenario of the general imidacloprid toxicity. Thus, presented results suggest the cytotoxicity of imidacloprid low doses in non-target organisms and hypothesize that NSE downregulation could be estimated as a biomarker of neonicotinoid cytotoxicity in a nervous system of non-insect species.

Abstract: Field experiment was conducted in Giza, Egypt, during two growing seasons of 2017-2018 and 2018-2019 on garlic crop, with the objective of investigating the effect of different irrigation levels (60, 80 and 100 % of water requirements and their combination with the foliar spraying applications of agrispon (with 0.5 and 1.0 ml/ liter) on growth and yield. The results indicated that increased irrigation level up to 100% led to increased vegetative characters of garlic and that the lowest growth and productivity was obtained by 60% irrigation level. When considering spray application of agrispon; with 1.0 ml/L increased growth and productivity followed by 0.5 ml/L; while control treatment gave the lowest productivity during the both seasons. Interaction effect between irrigation level and agrispon treatments indicated that 100% irrigation level combined with 1.0 ml/L spray application of agrispon gave the highest garlic productivity followed by 100% irrigation level combined with 0.5 ml/L spray application. The chemical analysis showed that the highest NPK was obtained by 100% irrigation level combined with 1.0 ml/L agrispon application during the both seasons. Regarding water footprint, the highest irrigation water footprint was obtained by 80% irrigation level followed by 60% irrigation level, while the lowest footprint was obtained by 100% irrigation level due to high garlic productivity under 100% irrigation level. The estimate water footprint for garlic was 525 m³/ton. The blue water footprint for garlic was 422 m³/ton about 80% form total water footprint, while gray water percentage about 20% with value of 103 m³/ton.