ARS | Publication request: EFFECT OF ELEVATED COPPER ON THE PHENOLIC COMPOUNDS OF SPINACH (SPINACEA OLERACEA L.) LEAF TISSUES

Submitted to: Journal of Plant Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 19, 2002
Publication Date: N/A

Interpretive Summary: Copper-containing chemicals are used in agriculture as fungicides. However, excess copper can results in plant damage. In this study, the effect of copper solutions on the flavonoids of spinach leaves was investigated. At low concentrations, copper reduced flavonoid levels in spinach leaf extract analyzed by high-performance liquid chromatography. Since plant flavonoids may help protect plants from environmental stresses and provide specific human health benefits, any significant reduction of these compounds in vegetable crops could limit plant growth under certain environmental conditions and diminish the nutritional qualities of vegetables.

Technical Abstract: The effect of copper (Cu(II)) on the phenolic compounds of spinach (Spinace oleracea L.) leaf tissues was investigated. Leaf disks (7 mm) were exposed to CuSO4.5H2O concentrations from 50uM (12.5 ppm) to 2.5 mM (625 ppm) at p from 4.0 to 9.0 for 24 hr in both the light and dark. Acidified, aqueous methanol (flavonoid-rich fraction) extracts were analyzed by high performance liquid chromatography. Cu(II) altered the levels of the phenol compounds, increasing the levels of some compounds at low Cu(II) concentrations and decreasing the levels of all the phenolic compounds at higher Cu(II) levels. In most cases, the magnitude of the Cu(II)-induced changes in spinach phenolics was independent of treatment pH. These Cu(II)- induced changes in phenolic compounds may modify plant responses to environmental or biotic stresses and alter the nutritional values of certai vegetable crops