Adverse effect of high phosphorus on plant zinc concentration expressed differently in wheat plants grown in soil and nutrient solution

Official URL: http://risc01.sabanciuniv.edu/record=b1534392

Zinc (Zn) deficiency is a global micronutrient deficiency in agricultural soils. One of the major causes of the widespread occurrence of Zn deficiency is related to its interactions with other nutrients during root absorption, especially with phosphorus (P). In this study, soil and nutrient solution culture experiments were conducted on wheat to examine how increasing P supply affects root Zn uptake and shoot and grain Zn concentrations of plants which were grown under different Zn treatments. Part of the soil experiments has been realized by using autoclaved (sterilized) soils. In the experiments with native soil, there were substantial decreases in shoot and grain Zn concentrations by increasing P applications. Under low Zn supply, increasing P supply also caused decreases in yield and promoted expression of Zn deficiency symptoms. Treatment of the native soil with increasing P supply also resulted in significant depression in mycorrhizal inoculation of roots. In contrast to the results obtained with native soil, Zn concentrations of the plants were slightly affected by increasing P supply when grown in sterilized soil (without mycorrhizae). In case of nutrient solution, enhancements in P supply had either no effect or even stimulated root Zn uptake. Based on these findings, it is suggested that high P itself in nutrient or soil solution has not an adverse effect on chemical solubility or root uptake of Zn in soils. The well-documented reducing effect of increasing P supply on root Zn uptake is most probably related to decline in mycorrhizal activity in rhizosphere.