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Determination of the Copper 2+ Activity Required by Maize Using Chelator‐Buffered Nutrient Solutions
Author(s) -
Bell Paul F.,
Chaney Rufus L.,
Angle Jay S.
Publication year - 1991
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1991.03615995005500050028x
Subject(s) - chelation , hydroponics , reagent , copper , chemistry , nutrient , shoot , ethylenediamine , micronutrient , yield (engineering) , nuclear chemistry , dry matter , zea mays , inorganic chemistry , agronomy , biology , materials science , metallurgy , organic chemistry
Hydroponics is a useful method to study micronutrient deficiencies in plants. Problems in using this method to study Cu deficiencies are: (i) control of Cu supply to induce any degree of deficiency is difficult, (ii) purification of reagents is required to induce severe deficiency; and (iii) when chelators are added to induce Cu deficiency, the chelators may inactivate Fe, making Fe unavailable to plants. Mild to severe Cu deficiencies were induced in maize ( Zea mays L.) without the purification of reagents using chelators HEDTA [N‐(2‐hydroxyethyl)ethylenediamine triacetate] with and without BPDS (4,7‐diphenyl‐1,10‐phenanthrolinedisulfonic acid) to bind and inactivate Cu. GEOCHEM‐PC was used to calculate the quantity of free and chelate‐bound Cu. A wide range in leaf and root Cu concentrations was observed from plants grown in HEDTA solutions with calculated solution Cu 2+ activities of 10 −15.4 to 10 −12.4 M . The calculated Cu 2+ activity associated with a 20% reduction in yield was 10 −14.5 M (control plants yielded 15 g dry matter at 18 d). Solutions containing HEDTA with BPDS and the lowering of nutrient‐solution Ca concentrations were evaluated as means of inducing severe Cu deficiency. Maize grown in BPDS‐added solutions were severely stunted regardless of Ca treatment, and had significantly lower shoot Cu, Mn, and Fe concentrations than those found in other treatments. Results indicated Cu availability to maize was controlled by Cu 2+ and not Cu + activity. HEDTA, especially in combination with BPDS, can effectively induce Cu deficiency and supply adequate Fe to maize.