Induced Fe-Deficiency-Chlorosis Severity in Soybean using EDTA-Buffered Nutrient Solutions | ||
| Egyptian Journal of Soil Science | ||
| Article 6, Volume 53, Issue 1, March 2013, Pages 67-74 PDF (322.36 K) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/ejss.2013.141 | ||
| Abstract | ||
| CHELATOR-buffered nutrient solutions have been used to control.Fe photo availability for dicots in a number of studies, but the use of diethylenetriaminepentaacetic acid (DTPA) required adding Zn, Cu and other trace elements at levels much higher than traditional nutrient solutions. In order to have lower levels of other trace element cations in the buffered solutions, ethylenediaminetetraacetic acid (EDTA) was used to impose varied levels of Fe stress to soybean (Glycine max L.Merr., cv Williams-82). In addition to a control treatment (no FeEDTA added), FeEDTA was supplied at 0.32, 1.00, 3.16, 5.00, 10.0, 20.0 and 50.0 μM in pH buffered 0.5 Johnson solutions. Enough EDTA was added to chelate all of the micronutrient cations plus 100 μM of “excess” EDTA which is largely chelated with some of the Ca2+ in the nutrient solution. Plant dry matter significantly corresponded with Fe activity in solution. The highest dry matter was obtained with 20 and 50 μM Fe (plants remained green throughout the experiment). At intermediate levels (1-10 µM FeEDTA) plants had mild or moderate chlorosis and remained at a steady chlorosis rating until harvest. Over time, the leaves with 0 and 0.32 µM FeEDTA became severely chlorotic. Analysis showed that trifoliolate leaf Fe corresponded with chlorosis severity, while all other microelements were present at normal concentrations of healthy soybeans, although somewhat increased due to smaller biomass dilution. The EDTA-buffered Johnson solution offers a strong control of Fe stress at varied severity and should provide a valuable tool for the study of microelement plant nutrition. | ||
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