The influence of deposits from copper mining and smelting combine Bor on the vegetation of riverside of the river Timok (Eastern Serbia)

The quantity of tail and other harmful products of RTB-Bor (Copper mining and smelting combine Bor) have significantly increased since the mid twentieth century, and were carried into the lower stream of the river Timok, mainly through the Borska River. Flooding the surrounding areas and producing thick deposits of substratum with the extreme characteristics caused the devastation and degradation of the autochthonous plant communities and large areas of arable land. This caused the appearance of new, atypical species such as Betula pendula Roth, Robinia pseudoacacia, Amorpha fruticosa, Calamagrostis epigeios, Erigeron Canadensis and other species in the devastated and degraded community of Salici-Populetum albae in the areas of Tamnic, Brusnik and Bracevac villages, and they have significantly changed typical floristic composition of the community.nul

The influence of deposits from copper mining and smelting combine Bor on the vegetation of riverside of the river Timok (Eastern Serbia)

The quantity of tail and other harmful products of RTB-Bor (Copper mining and smelting combine Bor) have significantly increased since the mid twentieth century, and were carried into the lower stream of the river Timok, mainly through the Borska River. Flooding the surrounding areas and producing thick deposits of substratum with the extreme characteristics caused the devastation and degradation of the autochthonous plant communities and large areas of arable land. This caused the appearance of new, atypical species such as Betula pendula Roth, Robinia pseudoacacia, Amorpha fruticosa, Calamagrostis epigeios, Erigeron Canadensis and other species in the devastated and degraded community of Salici-Populetum albae in the areas of Tamnic, Brusnik and Bracevac villages, and they have significantly changed typical floristic composition of the community.nul

Phenolic acids distribution in a peat of the relict community with Serbian spruce in the Tara Mt. forest reserve (Serbia)

Restoration of tertiary endemorelict Serbian spruce (Picea omorika Pancic) in forest-peat in Tara Mt., the only such finding in the world is rather poor. This could be partially ascribed to the presence of phenolics in peat soil. Content of total phenols and phenolic acids was determined in peat samples taken from: (1) knolls of forest-peat bog with dominance of trees and between the knolls and (2) peat bog knolls with dominance of Agrostis alba and between the knolls where Sphagnum mosses prevailed. In knoll samples of forest-peat bog where there are conditions for growth and development of trees, the amount of free phenolics was up to three times higher compared to that in the peat-bog knoll samples with dominance of A. alba. Amount of bound phenolics between the knolls of forest-peat bog was significantly higher than that between the knolls of the peat bog. Content of bound phenolics. exceeded that of free ones 1.77-12 times. In the forest-peat bog soil, derivatives of benzoic acid mainly originating from woody plants were dominant, while in peat bog cinnamic acid derivatives, originating from A. alba and Sphagnum mosses prevailed. Our results demonstrate that aerobic conditions in knolls enable a more extensive accumulation of free phenolics, while anaerobic conditions between the knolls result in a higher accumulation of bound phenolics. Content and composition of phenolic compounds depend on dominant plants in phytocoenotic microcomplex, as well as characteristics of the microhabitat. (C) 2003 Editions scientifiques et medicales Elsevier SAS. All rights reserved.nul

Allelopathic potential of Allium ursinum L.

Allium ursinum L. (wild garlic) represents a widely distributed plant species in beech and mixed beech-fir forests of Serbia. It forms dense populations in which the other species are either sparsely present or absent. Its allelopathic influences were studied using both the seeds and seedlings of test plants (lettuce, amaranth and wheat) and by analyzing phenolic acids and total phenolics in the leaves, bulbs and soil. Aqueous extract and volatile compounds of the bulbs were stronger inhibitors of seed germination and seedling growth compared to those of the leaves. The soil and phenolic-containing fraction of the soil under Allium ursinum also inhibited seed germination and growth of test plant seedlings. The bulbs and the leaves were found to contain 2.30 mg/g and 3.24 mg/g (dry weight) of total free phenolics, respectively, and the same amount of bound phenol forms (1.0 mg/g). Among allelopathic matter in bulb and leaf extracts, p-coumaric, ferulic, p-hydroxybenzoic and vanillic acids as free and bound forms were identified (25.43-87.93 mug/g). The soil contained 0.16 mg/g free and 1.61 mg/g total bound phenolics and p-coumaric, ferulic, p-hydroxybenzoic, vanillic and syringic acids as free (1.00-9.65 mug/g) and bound forms (26.45-44.76 mug/g) were found. These results suggest that A. ursinum influences other herbaceous plants in plant community via soil and volatile compounds which inhibit seed germination and plant growth. (C) 2003 Elsevier Ltd. All rights reserved.nul

Allelopathic potential of Allium ursinum L.

Allium ursinum L. (wild garlic) represents a widely distributed plant species in beech and mixed beech-fir forests of Serbia. It forms dense populations in which the other species are either sparsely present or absent. Its allelopathic influences were studied using both the seeds and seedlings of test plants (lettuce, amaranth and wheat) and by analyzing phenolic acids and total phenolics in the leaves, bulbs and soil. Aqueous extract and volatile compounds of the bulbs were stronger inhibitors of seed germination and seedling growth compared to those of the leaves. The soil and phenolic-containing fraction of the soil under Allium ursinum also inhibited seed germination and growth of test plant seedlings. The bulbs and the leaves were found to contain 2.30 mg/g and 3.24 mg/g (dry weight) of total free phenolics, respectively, and the same amount of bound phenol forms (1.0 mg/g). Among allelopathic matter in bulb and leaf extracts, p-coumaric, ferulic, p-hydroxybenzoic and vanillic acids as free and bound forms were identified (25.43-87.93 mug/g). The soil contained 0.16 mg/g free and 1.61 mg/g total bound phenolics and p-coumaric, ferulic, p-hydroxybenzoic, vanillic and syringic acids as free (1.00-9.65 mug/g) and bound forms (26.45-44.76 mug/g) were found. These results suggest that A. ursinum influences other herbaceous plants in plant community via soil and volatile compounds which inhibit seed germination and plant growth. (C) 2003 Elsevier Ltd. All rights reserved.nul