The essential and beneficial roles of nickel In growth of soybean and wheat plants

Official URL: http://risc01.sabanciuniv.edu/record=b1534416 (Table of Contents)

Nickel (Ni), which is known to be the cofactor of urease, was the last element to be included in the list of essential micronutrients for higher plants. Although the Ni requirement of plants is very low, Ni deficiency was documented to occur under field conditions. However, most of the studies on plant Ni nutrition were conducted in hydroponics and focused on urea metabolism. In order to investigate the essential and beneficial roles of Ni in plant growth, several nutrient solution and soil culture studies were conducted on two major crops, namely soybean and wheat, under growth chamber and greenhouse conditions. Nickel deficiency reduced the seed yield in nitrate-fed soybean and caused impaired growth and toxicity symptoms upon foliar urea applications. Moreover, Ni deficiency resulted in physiological nitrogen (N) deficiency and reduced the N uptake and N use efficiency (NUE) of urea-fed plants. Using high-Ni seeds was a highly effective alternative to external Ni supply for alleviating the problems caused by urea. In wheat, soil and/or foliar applications of Ni improved the grain yield and NUE under ample N supply, indicating that Ni may be beneficial at levels much higher than required to fulfill its essential roles, depending on the conditions. Furthermore, foliar Ni applications were shown to provide protection against sublethal glyphosate, which can cause developmental abnormalities and dramatic yield losses in wheat. The use of Ni as a micronutrient may have great impacts on agricultural productivity, NUE and crop tolerance to glyphosate drift. These effects should be further investigated under field conditions.