engleski

Glucosinolates vs cadmium accumulation in the cultivated garden cress (Lepidium sativum L.): Resistance is futile?

Glucosinolates are specialised metabolites that are involved in plant response to biotic stress but can be significantly influenced by abiotic factors as well. They were found in over 16 plant families, the most important among them being Brassicaceae family [1]. Garden cress (Lepidium sativum L., Brassicaceae) is a fast growing annual herb, cultivated all over the world. To this date over 500 plants species are known to hyperaccumulate metals, among which the largest number of taxa belong to Brassicaceae family. According to the literary data, Cd-hyperaccumulators are plants that accumulate >100 ppm of cadmium and Cd-accumulators are plants that accumulate >20 ppm of cadmium without showing signs of phytotoxicity [2]. This study describes the cultivation of garden cress in the substrate and hydroponically. Two different studies were performed using substrate (400 grams, Compo Sana, Compo GmbH, Münster, Germany). In the first study, the garden cress was planted in the untreated substrate (3 grams of seeds in the substrate) and watered with 50 mL of five cadmium solutions (225, 450, 900, 1345 and 1800 ppm) during 30-day period, after the first germination was observed. In the second study, the same amount of garden cress seeds was planted in the mixture of substrate with addition of zeolite saturated with cadmium solutions of different concentration (225, 450, 900, 1345 and 1800 ppm) and watered exclusively with tap water. Additionally, cadmium solutions of different concentrations from 1 to 50 ppm were used for hydroponic growth. Sprout development was monitored for 7 days and it was observed that plant did not grow in the solution at 50 ppm Cd. All plant samples were analysed for their glucosinolate content using UHPLC-DAD-MS/MS, as well as their cadmium concentration using atomic absorption spectroscopy. The major glucosinolate detected in all the samples was glucotropeolin, the content of which was significantly higher in the sprouts (190.96 - 217.04 µmol g-1 of dried weight) than in the plants grown in substrate with or without zeolite (0.36 - 0.51 µmol g-1 of dried weight). The plant grown in pure substrate accumulated the highest concentration of cadmium ranging from 115.19 to 1576.64 ppm. When using zeolite-substrate mixture cadmium content ranged from 39.66 to 158.10 ppm. Furthermore, the sprouts grown in different concentration of Cd-solutions accumulated from 52.35 to 240.57 ppm. Generally, plants exposed to different cadmium concentrations showed growth reduction, while the glucosinolate content did not vary. However, based on the obtained results it can be suggested that garden cress is a hyperaccumulator of cadmium.

glucosinolates ; selenium ; hyperaccumulation

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