Caracterização fotossintética e do desenvolvimento de plantas de batata-doce cultivadas in vitro e aclimatizadas

Abstract

Sweet potato is a species of economical importance that presents several factors that limit its productivity, of which the main one is the use of shoots and roots in order to obtain plantlets, favoring diseases dissemination, mainly viruses. Therefore, the tissue culture is of great importance for the production of plantlets with improved genetic and phyto-sanitary qualities. However, biochemical and environmental factors interfere in the metabolism in vitro, hindering the establishment of the plants during the aclimatization phase. The objective of this study was to analyze the influence of the sucrose and of the photon flux density in the development and in the photosynthetic capacity of sweet potato plants cultivated in vitro and aclimatizated. The photon flux density of 42 µmol m -2 s -1 maximized growth and development and, the increase in sucrose concentration allowed a significant increase in photosynthetic pigment contents as well as an increase of plant biomass. For the determination of the photosynthetic characteristics (Potential Photosynthesis and Chlorophyll Fluorescence) were monitored in leaves generated in vitro and ex vitro, after transferring the plants to a greenhouse. The results demonstrated that the sucrose concentration of 20 g L -1 and the photon flux density of 21 µmol m -2 s -1 provided physiological conditions which allowed a more efficient adaptation during acclimatization. However, there was no effect of in vitro treatments in the photosynthetic performance of leaves generated ex vitro.