Interactions of oxygen‐nitrogen‐salinity stresses on plant growth and mineral content of sunflower (Helianthus annuus L.) in sand culture

Abstract

Reports relating the separate and combined influences of soil aeration, nitrogen and saline stresses on the germination, growth and ion accumulation in sunflowers are lacking in the literature.The sunflowers of this report were grown in sand culture in the greenhouse. Separate and combined treatments of two levels of aeration, three levels of nitrogen and three levels of NaCl were applied to plants which were harvested at 40 and 56 days. Seed germination was excellent in all treatments. Plant height and dry weight decreased with each type of stress. Low oxygen (0.20 μg O 2 cm -2 min -1 ) and nitrogen (10 ppm) combined with 70 meq/1 NaCl caused the greatest reduction of plant growth. Leaf number was reduced by low nitrogen and excess salt. Low oxygen reduced the accumulation of K, Ca and Mg and increased the Na and N-NO 3 content of sunflower leaves. Potassium to sodium ratios in plant