Influence of Arbuscular Mycorrhizae on Heavy Metal (Pb and Cd) Uptake, Growth, and Chemical Composition of Vitis vinifera L. (cv. Razaki)

Abstract

The influence of arbuscular mycorrhizae (AM) on plant growth, mineral uptake as well as on soluble solids and acid content of the Razaki grapevine variety grafted onto 110R, in experiments with different amounts of Pb and Cd heavy metals, was studied. Mycorrhizal and non-mycorrhizal plants were grown outdoors in pots containing soil, supplemented with 0, 50, 100, and 300 mg of Pb/kg or 0, 5, 10, and 50 mg of Cd/kg soil. After 3.5 years mycorrhizal colonization was varied from 26.3% to 58.7% in Pb treatments and from 44.7% to 53.3% in Cd treatments. In the same time spore population was varied from 126 to 266 spores per 100 g soil and from 186.7 to 264.0 spores in Pb and Cd treatments, respectively. Treatments receiving 300 mg Pb/kg and 50 mg Cd/kg in the soil showed a reduction in pruning weight compared with the control (0 mg Pb or Cd/kg). Mycorrhizal colonization significantly increased pruning weight in the control and the low Pb and Cd treatments (0, 50, and 100 mg/kg and 0, 5, and 10 mg/kg respectively). In elevated soil Pb supplements, the fruits had decreased total soluble solids and increased total acidity. With the changes to Cd level, berry soluble solids and acids were not affected. No significant differences of leaf N, K, Ca, Mg, and B nutrient concentrations were found between the heavy metal Pb and Cd treatments nor between mycorrhizal and non-mycorrhizal plants. The M/NM (mycorrhizal/non-mycorrhizal) ratio for N, K, Ca, and Mg concentrations varied from 1.0 to 1.2 and for B from 1.07 to 1,5. Leaf Mn, Zn, Fe, Cu, Pb, and Cd concentrations were lower in mycorrhizal plants compared to non-mycorrhizal plants and the M/NM ratios were less than 1.0. Berry Pb concentrations in the mycorrhizal plants were low (up to 20 mg/kg) in control and increased in Pb treatments (up to 463 mg/kg and 1315 mg/kg in M and NM plants, respectively). Appreciable Cd was detected only in the high Cd treatments, in which berry concentrations were 0.8 mg/kg and 2.5 mg/kg in the M and NM plants, respectively (50 mg of Cd/ kg).