The K/Na and Ca/Na ratios and rapeseed yield, under soil salinity or sodicity

Abstract

Rapeseed (Brassica napus) is a crop relatively tolerant to salt and sodium. Our objective was to study the interactions between Na, K and Ca and their relationship with its yield under the isolated effects of soil salinity or sodicity.Two experiments were carried out using pots filled with the Ah horizon of a Typic Natraquoll. There were three salinity levels (2.3 dS m-1; 6.0 dS m-1 and 10.0 dS m-1) and three sodicity levels, expressed as sodium adsorption ratios (SAR: 12; 27 and 44). The soil was kept near field capacity.As soil salinity increased, the K/Na and Ca/Na ratios in the tissues decreased markedly but yields and aerial biomass production were not affected. As soil SAR value increased, the K/Na and Ca/Na ratios in plants and K-Na and Ca-Na selectivities decreased. Plants could not maintain their Ca concentration in soil with a high SAR. The grain yield and biomass production diminished significantly in the highest SAR treatment. Our results are consistent with those showing detrimental osmotic effects of salts in Brassica napus. Conversely, under sodicity, the K/Na and Ca/Na ratios in plant tissues decreased considerably, in accordance with grain and biomass production. These results show that the effects of sodicity are different from those of salinity.

The influence of chloride deicers on mineral nutrition and the health status of roadside trees in the city of Kielce, Poland

“…The K/Na and Ca/Na ratios are indicative for soil salinity (Porcelli et al 1995). In the present study, these ratios were the highest at control sites (Fig.…”

Sodium as nutrient and toxicant

“…Indeed, the salt-including habit of many species in this family has been documented as early as 1896 (von Marilaun 1896). In more recent times, He and Cramer (1993) investigated K + /Na + ratios in shoot tissue of six Brassica species, near relatives of Arabidopsis, and found that they bore no relation to salt tolerance, while Porcelli et al (1995) showed that yields and shoot growth of Brassica napus plants were not correlated with tissue K + /Na + or Ca 2+ /Na + ratios.…”

Effect of Salinity Stress on Yield, Component Characters and Nutrient Compositions in Rapeseed (Brassica napus L.) Genotypes

“…Salinity impairs the uptake of Ca by plants, possibly by displacing it from the cell membrane or in some way affecting membrane functions (Rameeh et al, 2004;Mandhania et al, 2010). Gorham (1993) claimed that all plants discriminate to some extent between Na and K. Na can be substituted for K for uptake, and it is supposed that similar mechanisms of uptake may operate for both ions (Tie and Cramer, 1992;Porcelli et al, 1995;Schroder et al, 1994). High level of K in young expanding tissue is related to salt tolerance in many plant species (Ashaf and McNeilly, 2004;Bandeh-Hagh et al, 2008;Mer et al, 2000).…”