ARI Biennial Review for 2018-2019

INTEGRATED WATER RESOURCE MANAGEMENT AND IRRIGATION Research on integrated water resource management is currently devoted mainly to wastewater reuse in agriculture. Field experiments are performed for appraising the effects of wastewater reuse for irrigation purposes on the environment and on public health. In addition, field and hydroponic experiments are carried out in order to evaluate xenobiotic compounds (pharmaceuticals) uptake by plants. Pharmaceutically active compounds released in agroecosystems can be considered as emerging plant stressors Pharmaceutically active compounds (PhACs) entering agroecosystems as a result of various human activities may be taken up by and accumulated within crop plants, with potential human health implications. Despite their extensive metabolism by a sophisticated enzyme-based detoxification system in plant cells, PhACs and their transformation products (TPs) may result in adverse effects on plants’ physiology. PhACs–mediated phytotoxic effects, as well as plants’ defense responses have been depicted on plants exposed to individual or low number of PhACs under controlled conditions. Cocktails effects and synergistic interactions of the mixtures of PhACs in actual agroecosystems towards phytotoxicity should be taken into consideration. Considering PhACs as emerging plant stressors will better facilitate the understanding of their phytotoxic effects. ( A. Christou ) Uptake and bioaccumulation of three widely prescribed pharmaceutically active compounds in tomato fruits and mediated effects on fruit quality attributes This study aimed at evaluating: 1) the uptake and bioaccumulation of three common PhACs (diclofenac, DCF; sulfamethoxazole, SMX; trimethoprim, TMP), either applied individually (10 μg L −1 ) or as mixture (10 μg L −1 each) in tomato fruits, and 2) the PhACs-mediated effects on fruit quality attributes. DCF was not detected in tomato fruits, whereas both SMX and TMP were detected in varying concentrations in fruits, depending on the time of harvest, the mode of application and the allocation of plants in the greenhouse. Important fruit quality attributes, such as soluble solids and carbohydrate (fructose, glucose, sucrose, total sugars) content were significantly impacted by all studied PhACs applied individually. In addition, no additive or synergistic effects of the mixture of PhACs on studied fruit quality attributes were revealed. Gene expression analysis showed that the impacts on the carbohydrate content of fruits can be attributed to the significant modulation of the abundance of transcripts related to the biosynthesis and catabolism of sucrose, such as SlSuSys, SlLin5 and SlLin7. ( A. Christou ) Ranking of crop plants according to their potential to uptake and accumulate contaminants of emerging concern Contaminants of emerging concern (CECs) are routinely detected in TWW-irrigated agricultural soils and runoff from such sites, in biosolids- and manure-amended soils, and in surface and groundwater systems and sediments receiving TWW. Crop plants grown in such contaminated agricultural environments have been found to uptake and accumulate CECs in their tissues, constituting possible vectors of introducing CECs into the food chain; an issue that is presently considered of high priority, thus needing intensive investigation. Both biotic (e.g. plants’ genotype and physiological state, and soil fauna) and abiotic factors (e.g. soil pore water chemistry, physico- chemical properties of CECs and environmental perturbations) have been proven to influence the ability of crop plants to uptake and accumulate CECs. According to authors’ estimates, based on the thorough elaboration of knowledge produced by existing relevant studies, the ability of crop plants to uptake and accumulate CECs decrease in the order of leafy vegetables> root vegetables> cereals and fodder crops> fruit vegetables; though, the uptake of CECs by important crop plants, such as fruit trees, is not yet evaluated. (A. Christou) 52 NATURAL RESOURCES AND ENVIRONMENT