Impact of Pseudomonads and Ethylene on the Cadmium and Nickel Rhizofiltration of Sunflower,Squash, and Indian Mustard |
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| Abstract: | Three hydroponic experiments were set up to study the rhizofiltration of cadmium (Cd) or nickel (Ni) from artificially contaminated nutrient solution with sunflower, squash, or Indian mustard. After 48 h of exposure with 2 mg L?1 Cd‐contaminated water, 460, 415, or 1092 µg Cd g?1 (dry weight) was detected in roots of 33‐day‐old sunflower and squash or in 50‐day‐old Indian mustard, respectively. As calculated, 1 g of root dry matter of the tested crop species removed 5.7–12.4% of total Cd content present in the nutrient solution. It was supposed that pseudomonads (soil rhizoplane bacteria) and the plant growth hormone ethylene can enhance the specific surface of roots and hence roots' metal adsorption capacity. As a trend, pretreatment of Indian mustard with Pseudomonas fluorescens bacteria enhanced slightly the Cd (from 1793 to 2346 µg g?1) or Ni (from 1088 to 1192 µg g?1) concentration of roots. Cadmium concentration in roots was also enhanced from 2694 to 3273 µg g?1 when the roots of Indian mustard were pretreated with Cd‐tolerant rather than Cd‐sensitive Pseudomonas cepacia. In spite of the occurrence of new root hairs, the pretreatment of roots with ethylene proved to be ineffective in enhancement of the Cd rhizofiltration capacity of Indian mustard. |
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| Keywords: | Cadmium and nickel rhizofiltration ethylene Indian mustard pseudomonads squash sunflower |
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