Amelioration of copper toxicity by iron on Spinach physiology

Abstract

The effect of excess copper (Cu) on young spinach (Spinacia oleraced) as well as the role of iron (Fe) for amelioration of toxicity on growth and photosynthesis in Cu-treated plants was evaluated. Plants treated with 160 μM Cu showed symptoms of heavy metal toxicity, while addition of Fe (40 μM) ameliorates to a certain extent toxic effects of Cu, due to antagonistic action between Cu and Fe. Root length and biomass revealed a lower decrease under Cu+Fe than under Cu treatment. Copper accumulation in plant tissues increased, while Fe, sodium (Na), potassium (K), calcium (Ca), and magnesium (Mg) declined under Cu treatment. The significant increase in chlorophyll fluorescence (F o ) under 160 μM Cu, possibly reflects the more severe damages suffered at the membrane level with respect to Cu+Fe treatment. Copper decreased the efficiency of excitation energy capture by PSH reaction centers and negatively affected the effective antenna size of PSH. Changes in the rate 2089 OUZOUNIDOU ET AL. of carbon dioxide (CO 2 ) assimilation were associated with changes in both stomatal conductance (gs) and mesophyll capacity for photochemistry as well as with lower pigment content. Net CO 2 assimilation, transpiration rate, and stomatal conductance were reduced. These changes at PSII are characteristic of a saturation of photosynthetic metabolic activity. The results suggest a tight linkage between PSII activity and CO 2 fixation under Cu treatment. Amelioration of Cu toxicity was obvious under Fe application.

Hormone-induced protection of sunflower photosynthetic apparatus against copper toxicity

“…The analyzer was calibrated with two standard CO 2 /air mixtures. Measurements were made at 25 °C under a photon flux density of about 750 µmol m -2 s -1 (for details see Ouzounidou et al 1998). P N , and E were calculated from gas exchange measurements according to Caemmerer and Farquhar (1981).…”

The effect of excess copper on growth and physiology of important food crops: a review

“…In spinach (Spinacia oleracea L.), 160 μM Cu in the solution culture decreased chlorophyll content by 45 % over control treatment (Ouzounidou et al 1998). Higher Cu (7 and 10 μM) in the nutrient solution decreased photosynthetic pigments in maize plants (Mocquot et al 1996), and 0.5 mM Cu supply in the growth medium decreased chlorophyll contents in cauliflower (Chatterjee and Chatterjee 2000).…”

Effect of Copper on Antioxidant Enzyme Activities and Mineral Nutrition of White Lupin Plants Grown in Nutrient Solution

“…However, in our results, we did not detect any difference in Mg levels and only a slight decrease in calcium content in roots and a small increase in leaves. Mocquot et al (1996) observed an increase in calcium and magnesium levels with increasing copper concentrations in young maize leaves, while Ouzounidou et al (1998) found a decrease in Ca, Mg, Fe, K and Na in both roots and leaves of spinach grown in 0.160 mM copper. Yang et al (2002) reported changes in nutrient uptake both in roots and in shoots of Cu-tolerant Elsholtzia splendens.…”