Crescimento in vitro de plantas de clones de batata expostas ao arsênio

Abstract

Environmental pollution by metalloids has increased a lot as a result of anthropogenic actions, such as industrial activities and the use of chemicals in agriculture. Arsenic (As) is among the metals that present the greatest environmental risks, due to the highest toxicity and wide distribution. The absorption and accumulation of As by plants is very variable among species and cultivars, with the intake of vegetables and bioaccumulation in the food chain being the main sources of population contamination. The main objective of this research was to evaluate the in vitro growth of plants exposed to As of potato clones. The experiments were carried out at the Tissue Culture Laboratory of the Plant Breeding and Vegetative Propagation Center of the Federal University of Santa Maria. In experiment 1, plants of the clone SMINIA793101-3 were tested in the concentrations of 10, 20, 30, 40, 50, 60 and 70μM of As in the culture media. The percentages of survival and rooting, the height of the aerial part and the number of leaves and roots were evaluated at 14 and 28 days after inoculation (DAI). The results indicated that potato plants of the SMINIA793101-3 clone showed high sensitivity to As exposure at 14 days of in vitro cultivation for all the evaluated traits. Based upon growth responses in As media, the As concentrations of 20, 40 e 60μM should be evaluated in other potato clones. Therefore, in the experiment 2 the clones SMINIA793101-3, SMIJ461-1, SMINIA00017-6, Asterix, Vivaldi, Macaca, Dakota Rose and Michigan Purple were evaluated. At 14 DAI, the percentages of survival and rooting, the height of the aerial part and the number of leaves and roots, and at 28 DAI, the activity of the enzyme catalase were evaluated. The results indicated that the concentrations of 0, 20, 40 and 60 μM As in the culture media can be used for the in vitro evaluation of potato clones. The plants should be evaluated at 14 days of cultivation in the presence of As. The addition of As to the culture media affected all traits of all evaluated clones of potato. The clones SMIJ461-1, Michigan Purple, and Macaca increased the activity of the catalase enzyme in the presence of As. Among the evaluated clones, Macaca showed the greatest increase in the catalase enzyme activity, indicating good ability to detoxify reactive oxygen species. In conclusion, the in vitro growth of potato plants in the presence of As differ among clones; the addition of As to the culture medium affects the catalase enzyme activity, shoot height, number of leaves and roots of potato plants; and the addition of 40 and 60μM As to the culture medium has adverse effects on the in vitro growth of potato plants.