Interactive effects of sulfur and nitrogen supply on the concentration of sinigrin and allyl isothiocyanate in Indian mustard (Brassica juncea L.)

The Interplay of Sulfur and Selenium Enabling Variations in Micronutrient Accumulation in Red Spinach

Aside from its importance in human and animal health, low levels of foliar-applied selenate (SeO4) can be advantageous in the presence of sulfur (S), contributing to improved growth, nutrient uptake, and crop quality. A hydroponic experiment in a growth chamber explored the interactive influence of Se and S on micronutrients and several quality indices, such as soluble sugars, organic acids, and total protein concentrations in spinach (Spinacia oleracea L.). Three levels of S (deprivation, adequate, and excessive) with varying quantities of Se (deficient, moderate, and higher) were examined in combination. Under S starvation and along with S nourishment in plant parts, Se treatments were found to cause noticeable variations in plant biomass and the concentrations of the examined elements and other quality parameters. Both Se levels promoted S accumulation in S-treated plants. Although the Se treatment had the opposite effect in shoots, it had a favorable impact on minerals (apart from Mn) in roots grown under S-limiting conditions. The S and Se relationship highlighted beneficial and/or synergistic effects for Mn and Fe in edible spinach portions. Reducing sugars were synergistically boosted by adequate S and moderate Se levels in roots, while in shoots, they were accumulated under moderate-or-higher Se and excessive S. Furthermore, the concentration of the quantified organic acids under S-deficient conditions was aided by various Se levels. In roots, moderate Se under high S application enhanced both malic acid and citric acid, while in the edible parts, higher Se under both adequate and elevated S levels were found to be advantageous in malic acid accumulation. Moreover, by elevating S levels in plant tissues, total protein concentration increased, whereas both moderate and high Se levels (Se1 and Se2) did not alter total protein accumulation in high S-applied roots and shoots. Our findings show that the high S and medium Se dose together benefit nutrient uptake; additionally, their combinations support soluble sugars and organic acids accumulation, contributing ultimately to the nutritional quality of spinach plants. Moreover, consuming 100 g of fresh red spinach shoot enriched with different Se and S levels can contribute to humans' daily micronutrients intake.

A Multi-Criteria Evaluation of the Effectiveness of Nitrogen and Sulfur Fertilization in Different Cultivars of Winter Rapeseed—Productivity, Economic and Energy Balance

This article presents the results of a three-year experiment involving a multi-criteria evaluation (productivity, economic and energy balance) of the effectiveness of nitrogen (N) and sulfur (S) fertilization in different cultivars of winter oilseed rape (open-pollinated, semi-dwarf hybrid, long-stem hybrid) grown in north-eastern (NE) Poland. The yield of the semi-dwarf cultivar was 11% lower than the yield of the long-stem hybrid cultivar and 18% higher than the yield of the open-pollinated cultivar. In all cultivars, N fertilization improved yields up to a rate of 180 kg ha−1 and up to a rate of 230 kg ha−1 in years with low precipitation in spring and summer. Seed yield increased in all cultivars in response to S fertilization at 40 kg ha−1. Higher rates of N fertilizer decreased the content of crude fat and glucosinolates (GLS) and increased the concentration of total protein in all cultivars. Sulfur fertilization increased the content of total protein (in long-stem cultivars) and GLS (in all cultivars). Production costs ranged from €542–624 ha−1 (≤130 kg N ha−1) to €619–697 ha−1 (≥180 kg N ha−1). The demand for energy in the production of winter rapeseed ranged from 14.5–19.3 GJ ha−1 (≤130 kg N ha−1) to 22.4–27.0 GJ ha−1 (≥180 kg N ha−1).

Effect of growth temperature on glucosinolate profiles in Arabidopsis thaliana accessions

Glucosinolates are plant secondary metabolites with important roles in plant defence against pathogens and pests and are also known for their health benefits. Understanding how environmental factors affect the level and composition of glucosinolates is therefore of importance in the perspective of climate change. In this study we analysed glucosinolates in Arabidopsis thaliana accessions when grown at constant standard (21 °C), moderate (15 °C) and low (9 °C) temperatures during three generations. In most of the tested accessions moderate and pronounced chilling temperatures led to higher levels of glucosinolates, especially aliphatic glucosinolates. Which temperature yielded the highest glucosinolate levels was accession-dependent. Transcriptional profiling revealed also accession-specific gene responses, but only a limited correlation between changes in glucosinolate-related gene expression and glucosinolate levels. Different growth temperatures in one generation did not consistently affect glucosinolate composition in subsequent generations, hence a clear transgenerational effect of temperature on glucosinolates was not observed.

Selenium influences glucosinolate and isothiocyanates and increases sulfur uptake in Arabidopsis thaliana and rapid-cycling Brassica oleracea

This study investigated the impact of Se on glucosinolates (GSs) and isothiocyanates (ITCs). Plants of Arabidopsis thaliana cv. Columbia and a rapid-cycling base population of Brassica oleracea were grown hydroponically under different Se and S concentrations. The objective was to determine the effects of increasing Se and S concentrations on the GSs and ITCs. The results indicate that S and Se concentrations increased in A. thaliana and B. oleracea leaf tissue in response to increasing Se treatments. Aliphatic and total GSs decreased significantly (P ≤ 0.001) from 0.0 to 3.2 mg Se L(-1) in B. oleracea and A. thaliana leaf tissues. Consequently, aliphatic and total ITCs decreased significantly (P ≤ 0.001) from 0.0 to 3.2 mg Se L(-1) in B. oleracea and A. thaliana leaf tissues. Data demonstrate that high levels of anticarcinogenic GSs can be maintained as the Se concentration is increased to 0.8 mg L(-1). Thus, it is feasible to increase Se to beneficial dietary levels without compromising GS concentrations.

Effect of differential N and S competition in inter- and sole cropping of Brassica species and lettuce on glucosinolate concentration

Field and greenhouse pot experiments were conducted to evaluate the potential to use intercropping as an alternative method to increase glucosinolates in Brassicas by manipulating nitrogen (N) and sulfur (S) balance by intercropping with lettuce (Lactuca sativa L. var. capitata). In both experiments, four combinations of N and S fertilization were used. In the field experiment no effect of intercropping on the total glucosinolate concentration was found as the growing lettuce was strongly inhibited by the presence of broccoli (Brassica oleracea L. var. italic). In contrast to this, in the pot experiment both total and individual glucosinolate concentrations in red leaf mustard (Brassica juncea L.) increased by intercropping. Fertilization treatments influenced glucosinolate concentrations in both experiments, and an interaction between N and S fertilization was noticed.