ABSTRACT: Cadmium (Cd) is a heavy metal that is extremely dangerous to human health and can be found naturally in soils, deposited through industrial waste or phosphate fertilization. In this study, we evaluated the morphological responses of in vitro grown plants of potato in the presence of Cd, and define a procedure for assessing Cd sensitivity of different clones. The potato clone SMIJ461-1 was cultured in the presence of Cd at concentrations of 0, 20, 40, 60, 80, 90, 110, 120, 140, and 160 µM. Survival, rooting, number and height of shoots, leaf and root counts were evaluated at 7, 14, 21, and 28 days of cultivation. Adverse effects of Cd on the growth of the potato plants, exerted in a concentration-dependent manner, were observed for shoot height, leaf and root counts. Results of this study indicated that Cd concentrations of 0, 45, 90, and 135 µM can be used for future in vitro evaluation of potato clone sensitivity to Cd exposure.

RESUMO: O cádmio (Cd) é um metal pesado extremamente perigoso à saúde humana, podendo ser encontrado naturalmente nos solos, depositado através de resíduos industriais ou da adubação fosfatada. Este trabalho teve por objetivo avaliar as respostas morfológicas de plantas de batata cultivadas in vitro na presença de Cd e definir uma metodologia para inferir sobre a sensibilidade de diferentes clones. Foi estudado o clone SMIJ461-1 de batata, nas concentrações de 0, 20, 40, 60, 80, 90, 110, 120, 140, 160 µM de Cd adicionadas ao meio de cultura. A sobrevivência, o enraizamento, o número de brotações, a altura da parte aérea e o número de folhas e raízes foram avaliados aos 7, 14, 21 e 28 dias de cultivo. Foram observados efeitos adversos de concentrações de Cd sobre o crescimento in vitro das plantas de batata do clone SMIJ461-1 para a altura da parte aérea e o número de folhas e raízes, sendo estes efeitos dependentes das concentrações de Cd adicionadas ao meio de cultura. Os resultados deste estudo indicam que as concentrações de 0, 45, 90 e 135 µM de Cd podem ser utilizadas para a avaliação in vitro da sensibilidade de clones de batata a presença de Cd.

ABSTRACT Onion production is conditioned to the adopted techniques during the cultivation. Sowing depth, soil preparation and cultivars are determinant factors for productivity to be increased. Two experiments were developed, the first with the objective of evaluating the effect of sowing depths and soil preparation methods on the germination and development of onion seedlings, while the objective of the second was to evaluate the productivity of onion cultivars as a soil preparation function. In experiment I, the split plot scheme was adopted, where the main plots consisted on soil tillage methods (total area and bed) and in the subplots, the sowing depths (0.5; 1.0; 1.5 and 2.0 cm), with six replicates. Experiment II was carried out in a split plot scheme, in which the main plots consisted on soil tillage methods (total area and bed) and in the subplots, such as onion cultivars (Itajubá, Rainha, Salto Grande, Ômega, Mulata and BR29), with four replicates. The 1.5 cm sowing depth provided greater speed of germination and plant stand. Raising beds offers the best initial seedling development. The onion cultivation under beds offers the highest vegetative development and productivity.