Heavy metal pollution of agricultural soils and air is one of the most severe ecological problems on a world scale and in Bulgaria in particular. The biggest sources of pollution in Bulgaria are some non-ferrous metals smelters, such as the Non -Ferrous Metals Combine (NFMC) near Plovdiv, situated on very fertile soils. Vegetable, arable and animal production in this area results in contaminated produce with excessive amounts of Cd, Pb, Cu, Mn and Zn.In order to discover some crops which could be grown on these areas without contamination of the end product, we conducted (in 1991-1993) field experiments in the vicinities of NFMC near Plovdiv. As experimental material we used Mentha piperita L. (cv Tundza and Clone No 1) and Mentha arvensis var piperascens Malinv. (cv . Plants have been grown on three Plots: Plot No 1 -at a distance of 400 m from the source of pollution; Plot No 2 -at 3 km from the source of pollution and on a control Plot -in the experimental gardens of University of Agriculture in Plovdiv, at 10 km from the source of pollution. It was established that heavy metal pollution of soil and air at a distance of 400 m from the source of pollution decreased the yields of fresh herbage by 9-16% and the yield of essential:oil by up to 14% compared to the control, but did not negatively affect the essential oil content and its quality.Oils obtained from Plot 1 at a distance of 400 m from the source of pollution have not been contaminated with heavy metals.Cultivar response to heavy metal pollution was established. A positive correlation between Pb concentration in leaves and in essential oil was found.Heavy metal concentration in the plant parts was found to be in order: for Cd roots > leaves > rhizomes > stems; Pb roots = leaves > rhizomes = stems; Cu roots > rhizomes = stems = leaves; Mn roots > leaves > stems = rhizomes; Zn leaves > roots > stems = rhizomes.The tested cultivars of peppermint and cornmint could be successfully grown in highly heavy metal polluted areas, as in the area around NFMC near Plovdiv, without contamination of the end product -the essential oils.Despite of the yield reduction (up to 14%), due to heavy metal contamination, mint still remained a very profitable crop and it could be used as substitute for the other highly contaminated crops.

L. 2008. The effect of cultivar and applied nitrogen on the performance of Camelina sativa L. in the Maritime Provinces of Canada. Can. J. Plant Sci. 88: 111Á119. Worldwide, oilseed demand is steadily expanding. This study assessed the novel oilseed crop Camelina sativa L. in the Maritime Provinces of Canada. Evaluations of cultivar and applied N were performed at Truro, NS, Harrington, PEI, and Hartland, NB, in 2005 and. The results show that the selection of cultivar is an important determinant for the potential success or failure of C. sativa production. Differences in plant stand, plant height, seed yield, oil content and fatty acid profile were found among the cultivars. The cultivar Calena provided the most consistent performance in terms of plant establishment, yield and oil content across all year-sites. Plant height, seed yield, oil content, total plant N and seed protein all responded to applied N rate. Applied N increased the seed yield of C. sativa, but the increase was not significant when the application rates were over 60 kg N ha(1 in NS or 80 kg N ha (1 in PEI. Plant height, total N content in plant tissue and seed protein content increased with increased N application, while oil content decreased. With the exception of erucic acid, all the main fatty acids in C. sativa oil responded to applied N levels or the interaction of N levels and year. Regression analysis showed that the contents of oleic acid and eicosenoic acid decreased with increased N application. The response of linolenic acid to N application was not consistent at each year-site. Results of this study provide convincing evidence of the agronomic suitability of C. sativa to the Maritime Provinces of Canada. Les re´sultats indiquent que le choix du cultivar joue un grand roˆle dans la re´ussite ou l'e´chec e´ventuels de la production de C. sativa. La densite´du peuplement, le rendement grainier, la teneur en huile et la composition en acides gras varient avec le cultivar. La varie´te´Calena est celle qui donne la performance la plus stable pour ce qui est de l'implantation, du rendement et de la teneur en huile pour l'ensemble des anne´es-sites. La hauteur du plant, le rendement grainier, la teneur en huile, la concentration totale de N dans la plante et celle de prote´ines dans la graine re´agissent tous a`la quantite´de N applique´e. L'amendement accroıˆt le rendement grainier de C. sativa, mais la hausse n'est pas significative aux taux supe´rieurs a`60 kg de N par hectare en N.-É . ou a`80 kg de N par hectare a`l'Iˆ.-P.-É . L'application d'une plus grande quantite´de N rehausse la hauteur du plant, la teneur totale de N dans les tissus et la concentration de prote´ines dans la graine mais on note une diminution de la teneur en huile. Outre l'acide e´rucique, tous les principaux acides gras de l'huile de C. sativa re´agissent a`l'application d'une quantite´supe´rieure de N. La re´action de l'acide linole´nique a`l'application de N est pas uniforme d'une anne´e-site a`l'autre. Les re´sultats de l'e´tude donnent des preuves convai...

L. 2008. The effect of seeding rate, seeding date and seeder type on the performance of Camelina sativa L. in the Maritime Provinces of Canada. Can. J. Plant Sci. 88: 501Á 508. The hypothesis of this study was that spring camelina (Camelina sativa L.) could be grown as a high-value crop under the moist, cool conditions of the Maritime Provinces in Canada and seeding date, seeding rate, and type of seeder will modify productivity and oil composition. The objectives were (1) to determine the optimum seeding date and seeding rate for camelina production in the Maritimes; and (2) to evaluate the effect of seeder type (seed drill and forage seeder) on camelina establishment and seed yield. A seeding date and rate experiment and a seeder type and seeding rate experiment were conducted in 2005 and 2006 in Nova Scotia and Prince Edwards Island. Seeding date did not affect camelina emergence, plant height, seed yield and oil content. The earlier seeding date increased the concentration of stearic acid in the oil compared with the later seeding date. Seed yield of camelina was not affected by seeding rate in the seeder type by rate trial but higher yields were observed up to 600 seeds m Á2 in the seeding date by rate trial. The weak yield response to seeding rate could be explained by the high yield compensation ability of camelina through branching. It was suggested that seeding rates in the range of 400 to 600 seeds m Á2 would likely be best for camelina grown in the Maritime region. The forage seeder provided a better crop stand compared with the seed drill, although both seeders provided satisfactory crop establishment. Camelina has the potential to be produced successfully in the Maritime Provinces due to its adaptability to seeder type, low seeding rate requirements, and a wide window for seeding date. J. Plant Sci. 88: 501Á508. L'hypothe`se a`la base de cette e´tude est que la came´line faux-lin (Camelina sativa L.) pourrait devenir une culture lucrative dans le climat frais et humide caracte´ristique aux provinces Maritimes du Canada. Les auteurs postulent aussi que la date d'ensemencement, la densite´des semis et le type de semoir modifieront le rendement de la culture et la composition de l'huile. Les objectifs e´taient les suivants : (1) de´terminer la date d'ensemencement et la densite´des semis optimales pour la culture de la came´line dans les Maritimes et (2) e´valuer l'incidence du semoir (a`grains ou a`cultures fourrage`res) sur l'e´tablissement de la culture et son rendement grainier. À cette fin, les auteurs ont entrepris une expe´rience sur la date d'ensemencement et la densite´des semis ainsi qu'une seconde sur le type de semoir et la densited es semis en 2005 et 2006, en Nouvelle-É cosse et a`l'Iˆle-du-Prince-É douard. La date d'ensemencement n'a aucune incidence sur la leve´e de la came´line, la hauteur du plant, le rendement grainier ni la teneur en huile. Des semis plus pre´coces augmentent la concentration d'acide ste´arique dans l'huile, comparativement aux semis plus tardifs. Le rendement grai...

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