METAL CONCENTRATIONS, GROWTH, AND YIELD OF POTATO PRODUCED FROM IN-VITRO PLANTLETS OR MICROTUBERS AND GROWN IN MUNICIPAL SOLID-WASTE-AMENDED SUBSTRATES

In vitro plantlets or microtubers (in vitro produced tubers) of 'Spunt a' potato (Solanum tuberosum L.) were planted in a 3 soil : 2 peat mos s : 1 sand substrate (by volume) amended with municipal solid waste (M SW) compost at 0, 10, 20, or 30 g 4(-1) L pot. Three months later, pla nt growth and tuber yield were evaluated and concentrations of shoot a nd tuber tin (Sn), arsenic (As), copper (Cu), zinc (Zn), nickel (Ni), lead (Pb), manganese (Mn), cadmium (Cd), and iron (Fe) were determined . Amending with MSW resulted in significant increases in concentration s of all tested metals in the substrate. Number of proliferated shoots of plants started from rooted plantlets was greatest at 10 g pot(-1) MSW, whereas shoot weight of plants started from microtubers was great est at 10 and 20 g pot(-1) MSW. Tuber yield of plants started from roo ted plantlets or microtubers was greatest at 10 or 30 g pot(-1) MSW, r espectively. In all instances, amending with MSW at 30 g pot(-1) resul ted in significant increases in concentrations of all tested metals in shoots and tubers. Concentrations of shoot Ni and tuber Zn and Fe for plants started from rooted plantlets and concentrations of shoot Fe a nd tuber As, Cu and Pb for plants started from microtubers increased c onsistently with increasing MSW percentage of the substrate. Plants st arted fi om rooted plantlets produced shoots with sufficient Zn, Mn, a nd Ni concentrations regardless of the substrate but with toxic Cu con tent at 30 g pot(-1) MSW. Plants started from microtubers produced sho ots with sufficient Mn and Ni concentrations regardless of the substra te but with low Zn and deficient Cu in unamended substrates. All plant s had shoot Fe content higher than the sufficiency range. Although the re were significant differences in concentrations of some nutrients am ong MSW treatments, no symptoms of nutrient toxicity or deficiency wer e observed. Ln all instances, tested elements did not accumulate in tu bers to levels hazardous to human health. Concentrations of Cd, the mo st hazardous element, in potato tubers was not high enough to pose a t hreat to human. Our results indicate that there is a potential use of MSW in satisfying the needs of potato growth with negligible increases in heavy metal concentrations in tubers.