Effect of salinity treatments on nutrient concentration in zucchini plants (Cucurbita pepo L. var. Moschata)

Abstract

Summary. Zucchini plants (Cucurbita pepo L. var. Moschata) grown in artificial soil under greenhouse conditions were supplied with differing amounts of NaCl (0, 30, 60 or 120 g/m² ) during the entire growth cycle. The concentrations of both total and soluble sodium, potassium, calcium and magnesium in leaves as well as fruit (skin and pulp) were measured.

Total sodium concentration in leaves increased with higher levels of applied NaCl, while in the fruit this trend was the reverse. As soil salinity increased, there was a corresponding decrease in the total and soluble potassium content of leaves but an increase in total and soluble concentrations of potassium in the fruit. The sum of both total and soluble sodium and potassium in the leaves generally increased with higher levels of applied NaCl, whereas the potassium : sodium ratio fell as salinity rose. In fruit, the sum of total and soluble sodium and potassium, as well as the potassium : sodium ratio, increased as the concentration of applied NaCl increased. The foliar levels of calcium and magnesium (except for total calcium readings) followed similar trends in relation to NaCl treatments as for sodium, while the response of calcium and magnesium in fruit tissues to the treatments was similar to that of potassium. Total calcium and magnesium levels were higher in leaves, with similar high levels in fruit tissues, these levels were higher when compared with other plants grown under saline conditions.