The dual effects of two inorganic selenium forms on the growth, selected physiological parameters and macronutrients accumulation in cucumber plants

Abstract

The boundary between beneficial and phytotoxic levels of selenium (Se) is narrow, and both induce alteration in plant growth and their physiology. In this study, the influence of two Se forms (selenite or selenate) with different concentrations (2-80 lM) on cucumber plants was investigated. The toxicity threshold for selenate and selenite was determined at the concentrations of 80 and 20 lM, respectively. In the Se-exposed plants, the growthpromoting effect was found at 6 lM of selenite and at 6-20 lM of selenate. The root activity considerably increased with increasing selenite concentrations suggesting the upregulation of mitochondrial dehydrogenases activity. Selenite treatment also impaired photosynthetic pigments accumulation and chlorophyll fluorescence parameters. Moreover, Se exerted a dual effect on lipid peroxidation in roots: at low concentrations it inhibited this process, whereas at high concentrations it enhanced the accumulation of harmful lipid peroxides. Under low Se concentrations (\10 lM), the accumulation of Se in shoots was similar in the presence of selenate and selenite. When Se concentration was [10 lM, the accumulation of Se in shoots was greater in selenate-exposed than seleniteexposed plants. However, in the roots the Se concentrations were always higher after selenite exposure comparing to selenate. The N level in plants was generally maintained constant, while the remaining macronutrients (especially K, P, and S) concentrations were significantly changed depending on the form and concentrations of Se. These results imply that an application of either selenate or selenite at concentrations\10 lM may be potentially used for biofortification of cucumber with Se and changes in plant macronutrient contents are not expected under these conditions.

Application of municipal biowaste derived products in Hibiscus cultivation: Effect on leaf gaseous exchange activity, and plant biomass accumulation and quality

“…However, neither any significant variation of Se nor correlation with N content was found in leaf tissues (data not shown). These findings did not help to explain the products' performance ranking order and were in agreement with previous works (Hawrylak -Nowak et al, 2015 andRios et al, 2013). Leaf N correlated (Fig.…”

Selenium Biofortification and the Problem of its Safety

“…From the point of view of plant nutrition, the effects of Se are twofold, since at low concentrations it can promote biofortification but at high concentrations it triggers toxicity in plants [64]. This duality of effects on plant growth is related to the narrow range between biofortification and toxicity, which in literature is not well established based on determination of critical Se levels.…”

The quality of carrot (Daucus carotaL.) cultivated in the field depending on iodine and selenium fertilization

“…This may indicate that carrot is a crop species less sensitive than lettuce to high doses of Na 2 SeO 4 when applied alone or together with iodine. It needs to be underlined that plant tolerance to selenates (IV) and selenates (VI) strongly depends on the cultivation system, whether hydroponics or in the field, with complex processes of sorption occurring in the latter (Ríos et al 2010, Hawrylak-Nowak et al 2015, Smoleń et al 2015, 2016a. Also in the case of iodine, carrot is far more tolerant to high doses of this element than other vegetable species, including spinach, pak choi and celery (Dai et al 2004).…”