Calcium ameliorates the toxicity of sulfate salinity in Brassica rapa

Abstract

Salinity stress in Brassica, often only associated with osmotic effects and the toxicity of Na, was more severe when applied as NaSO than as NaCl, indicating that SO ions had toxic effects as well. Application of 10 mM calcium in the form of CaCl in the growth medium of plants only slightly ameliorated growth impairment by NaCl and KCl, but almost completely prevented negative effects of NaSO and KSO on plant biomass production. This effect was calcium specific, as MgCl ameliorated sulfate toxicity to a much lower extent. This sulfate toxicity coincided with a strong decrease in the plant content of calcium and manganese upon sulfate salinity. Application of CaCl largely alleviated this decrease, however, it did not prevent the higher tissue concentration of sulfate. CaCl prevented the increase in organic sulfur compounds presumably by reducing of relative gene expression of ATP-sulfurylase (ATPS) and adenosine 5'-phosphosulfate reductase (APR) indicating a possible regulation of sulfate assimilation by calcium. The upregulation of the genes encoding for Group 4 sulfate transporters (Sultr4;1 and 4;2) upon sulfate salinity, was absent in the presence of CaCl. Therefore, additional calcium may facilitate an increased vacuolar capacity for sulfate accumulation.

Sulphur nutrition and iron plaque formation on roots of rice seedlings and their consequences for immobilisation and uptake of chromium in solution culture

“…5). As indicated earlier, sulphate salinity could reduce chelation and sequestration of Cr in roots (Reich et al 2015(Reich et al , 2018. Indeed, lower values of the S to Cr ratio in roots of rice seedlings treated with excessive rather than moderate S additions (Fig.…”

“…S6). An increase in the growth inhibition of crop plants supplied with S in the form of sulphate has been reported to be associated with a substantial reduction of Ca, Mg, and Mn contents induced by salt stress in plant tissues at early growth stages (Reich et al 2018). Intriguingly, when rice plants were supplied with excessive S levels, Cr exposure not only did not impose any apparent stress, but also promoted rice growth (Fig.…”

Impact of saline stress on the uptake of various macro and micronutrients and their associations with plant biomass and root traits in wheat

“…Under salt stress, Ca 2+ content may be one of the important factors limiting crop growth; hence, management practices that replace Na + from cation exchange sites with Ca 2+ can ameliorate high Na + and its adverse effects (Bronick and Lal 2005). Adding an appropriate amount of Ca 2+ has been shown to be a beneficial approach for alleviating salt stress on plant growth caused by Na or sulfate (Tian et al 2015, Reich et al 2018). However, contrary results of Severino et al (2014) suggest that Ca does not alleviate the toxic effects of Na on the emergence and initial growth of castor, cotton, and safflower.…”

Sulfur metabolism in Allium cepa is hardly affected by chloride and sulfate salinity

“…Some plant species such as wheat (Datta et al 1995), wild potato (Bilski et al 1988), barley (Huang and Redmann 1995), creeping screwbean (Reginato et al 2014), and cabbage (Paek et al 1988) were shown to be more susceptible to Na 2 SO 4 than to NaCl salinity. In Brassica rapa seedlings, sulfate salts (Na 2 SO 4 and K 2 SO 4 ) were more toxic than chloride salts (NaCl and KCl) (Reich et al 2016), and this toxicity is strongly ameliorated by calcium supplemented to the nutrient solution (Reich et al 2018). However there is still relatively little known about the mechanism of sulfate toxicity in plants.…”