Indução ao estresse salino na micropropagação de pitaia

Abstract

The pitaya is a culture tolerant to adverse environments, which makes it with potential use in affected areas, in addition to being appreciated for its sweet taste. Cultivation techniques such as tissue culture have been used to achieve a high multiplication rate with the control of environmental variables, in addition to enabling the selection of tolerant materials when exposed to selective agents. Cladode segments of the pitaya species Hylocereus undatus, Hylocereus polirhysus, Hylocereus megalanthus and hybrid Hylocereus polyrhisus x Hylocereus undatus were multiplied in vitro, submitted to concentrations of 0, 25, 50 and 100 mM of NaCl in order to evaluate the tolerance of the species as a function of the increase in NaCl concentrations. The phytotechnical characteristics were evaluated: number and length of shoots, plant and root length, fresh and dry biomass; and physiological relative water content, electrolyte leakage and photosynthetic pigments. The highest concentrations of NaCl were harmful to the development of pitaya species, so that, from the concentration of 25 mM, there was a reduction in the development of species that showed sensitivity, sometimes inhibiting the development of the species of yellow pitaya. The hybrid pitaya species was predominantly influenced by NaCl concentrations in physiological variables. The results obtained allow us to conclude that the yellow pitaya was sensitive to the increase of NaCl concentrations in the phytotechnical and physiological variables, the white and hybrid pitaya were, in general, tolerant and the red pitaya showed an intermediate behavior.