Plant tolerance to nickel toxicity: I. Influx, transport, and accumulation of nickel in four species

Abstract

Plant tolerance to nickel (Ni) toxicity depends on plant differences for uptake and distribution within tissues. Differences among and within species for Ni tolerance/accumulation might be used to identify or develop plants for remediation of high Ni soil conditions. Solution culture experiments were conducted under controlled conditions to determine influx (IN) into roots, transport (TR) from roots to shoots, and accumulation of Ni in four plant species grown at different Ni levels. White clover (Trifolium repens L.) had high dry matter (DM) at high Ni levels because of its low IN and TR of Ni. At Ni levels <60 μM, maize (Zea mays L.) had high DM probably because of its low TR even though it had high IN of Ni. Ryegrass (Lolium perenne L.) was sensitive to Ni toxicity because of its high IN and TR of Ni. The sensitivity of cabbage (Brassica oleracea var. capitata L.) to Ni toxicity was correlated with high TR even though it had low IN of Ni. Nickel accumulation in shoots was relatively high for cabbage and low for maize. Maize averaged ∼60‐fold less Ni in shoots than cabbage and ∼10‐fold less than ryegrass when plants were grown with <120 μM Ni. Plant tolerance to Ni toxicity was related to low IN of Ni, and especially to TR of Ni. Selecting or developing genotypes with low TR of Ni might improve plant tolerance to moderate Ni toxicity and reduce the flow of Ni from contaminated soils to shoot organs.

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Department of Crop & Soil Environmental Sciences, Virginia Polytechnic Institute and State University (VPI & SU), Blacksburg, VA 24061.

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