Tolerance to Zn deficiency and P-Zn interaction in wheat seedlings cultured in chelator-buffered solutions

Abstract

Zinc deficiency is a common constraint for wheat production in the regions with limited precipitation, particularly in the regions with high levels of available phosphate (P) in soil. Two experiments were conducted using chelator-buffered nutrient solutions to characterize differences in tolerance to Zn deficiency among three winter wheat (Triticum aestivum L.) genotypes and to investigate the relationship between P and Zn nutrition in wheat species. Four indices, Zn efficiency, relative shoot-to-root ratio, total Zn uptake in shoot, and shoot dry weight were used to compare the tolerance to Zn deficiency among three wheat genotypes. The results indicated that the four indices could be used in breeding selection for Zn uptake-efficient genotypes. The genotype H6712 was the most tolerant to Zn deficient, followed by M19, and then X13. Specifically, H6712 had the highest Zn uptake efficiency among the three genotypes. The addition of P to the growth medium increased Zn uptake and translocation from roots to shoots. Total Zn content of the wheat plant was 43% higher with 0.6 mmol/L P treatment than that of control with 0 mmol /L P treatment. The Zn translocation ratios from roots to shoots were increased by 16% and 26% with 0.6 mmol/L P treatment and 3 mmol/L P treatment, respectively, compared with 0 mmol/L P treatment. In contrast, high Zn concentrations in the growth medium inhibited P translocation from roots to shoots, but the inhibitive effects were not strong. Sixty-six percent of P taken up by wheat plants was translocated to the wheat shoots at 0 μmol/L Zn treatment, while the percent was 60% at 3 μmol/L Zn treatment. The result may be due to the fact that the wheat plants need more P than Zn.