The effect of different nitrogen and zinc doses on growth and yield in wheat

Zinc eficiency which induces several problems in plants, human, and animals is the most commonly occurring micronutrient disorder. Crop production and nutritional quality of edible parts of crop plants are decreased by Zn deficiency. Moreover, Zn is necessary for protein synthesis and plays a vital role in functions of many enzymes. It has been demonstrated that Zn deficiency gives rise to decreases in protein synthesis of plants and thus leads to the accumulation of soluble N forms, such as amino acids, in plants. This interrelationship between Zn and N has been investigated in a greenhouse experiment by studying the effect of different Zn (0.00, 0.02, 0.10 ve 5.00 mg kg-1) and N (25, 75 ve 225 mg kg-1) applications on dry matter and grain yield, and Zn, N, NO3 - and amino acid concentration in shoot and grain of Seri-82 that is wheat cultivar. It is found that 75 and 225 mg kg-1 N applications increased dry matter production of Seri-82 cultivar by 19.4 % and 38.5 %, respectively compared to 25 mg N kg-1 application. Also, Zn applications (0.02, 0.10 ve 5.00 mg kg-1) increased dry matter production cultivar by 14.4 %, 27.6 % and 67.4 %, respectively compared the control. It was observed that as the nutritional N status of crop improved, Zn?s effect on plant production was markedly increased. For example, while the rates of dry matter yield increases at the lowest N application (25 mg kg-1) were between, at it is found that the ratios of the dry matter increases with Zn applications changed 4.6 to 29.3 % compared no Zn, at 75 mg kg-1 N application same values changed 25.9 to 90.3 %. Similar enhancing effects of Zn on N nutrition were also observed. Concentrations of Zn, N, NO3 - and amino acids in shoots and grain were increased by N applications. In contrast, Zn applications lead to decreases concentration N, NO3 -, and amino acid contents but increased that of Zn. While amino acid concentration in shoots of cultivars without Zn applications was 9738 mg kg-1, with Zn applications of 0.02, 0.10 and 5.00 mg kg-1 same values were 5302, 4036 and 1990 mg kg-1, respectively. These results showed that Zn deficiency affects the accumulation of NO3 - and amino acid concentrations in shoots and grain of wheat. It is believed that this is related to impaired protein synthesis under Zn deficiency. The results also suggest that when Zn and N are optimized in nutritional zone, the growth and yield of crops could be increased while realizing reductions in contents of soluble N forms in plant. Therefore, the determination of Zn contents and N requirement of crops is of great importance. Keywords: Zinc, nitrogen, yield, amino acid and protein