ISHS Acta Horticulturae 462: I Balkan Symposium On Vegetables and Potatoes
THE EFFECT OF HEAVY METALS ON NODULATION AND MICROBIAL ACTIVITY IN THE RHIZOSPHERE OF THE PEA |
| Authors: | M. Jarak, M. Govedarica, . , M. Ubavic, N. Miloševic |
| Keywords: | Cd2+, Mo6+, Ni2+, Pb2+, micro-organisms |
| Abstract:
Heavy metals can either inhibit or stimulate microbiological processes in soil. The subject of the study was the effect of different concentrations of Mo6+, Pb2+, Ni2+ and Cd2+ on nodulation and microbial activity in the rhizosphere of the pea. Plants were grown in a greenhouse and treated with 10-3, 10-5 and 10-7 mol kg-1 soil of these metals fourteen days after emergence. The first heck (K1) treatment included soil without plants and heavy metals, whereas the second (K2) consisted of pea rhizosphere soil that had not been treated with heavy metals. Seven days later, microbiological analyses were done to determine the nodulation, the total number of bacteria, ammonifiers, azotobacter, as well as protease and dehydrogenase activity. The total number of bacteria was larger in the trial variants treated with heavy metals than in K1 but lower than in K2. The various concentrations of heavy metals applied reduced dehydrogenase activity compared to K2, but the activity was still high. The number of ammonifiers decreased in all treatments with heavy metals compared to K2 and increased with all concentrations of Ni2+ and Cd2+ compared to K1. The number of azotobacter in the rhizosphere was shown to have increased compared to K1 and in variants with 10-7 mol kg-1 soil of Pb2+ compared to K2. Application of heavy metals decreased root nodulation. | |
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