Análise fisiológica de variantes somaclonais e da memória transgeracional em plantas de cana-de-açúcar submetidas à deficiência hídrica

Abstract

The global interest in renewable energy sources is growing constantly and, consequently, the search for alternatives in the most diverse areas of knowledge. Sugarcane stands out in the Brazilian and global agribusiness scenario due to the high economic potential of its by-products. However, several factors can affect its productivity and the search for the development of new cultivation technologies is necessary. In this context, the objective of this study was to evaluate the physiological performance of clonal sugarcane plants subjected to water deficiency and how this stress can influence the physiological responses of two clonal generations. Spontaneous plants were used by in vitro tissue culture processing, named SP05, SP06, SP09 and SP10, and plants intercropped by vegetative propagation of toletes containing a single bud (Control). The experiment was conducted in a greenhouse and divided into two stages. In the first, a completely randomized design was used in the 2x5 factorial design, represented by two water regimes of 100% and 30% of daily water replenishment in relation to the field capacity and five different plants. In the second stage, the same experimental design was used with the plants originated from stalks of plants used in the first experiment. The experimental plot consisted of plastic pots containing 14.0 kg of soil with one plant per pot of the cultivar SP803280, with ten replications per treatment. The water deficit started at 120 days after planting (DAP) and during this period biometric and physiological evaluations were performed in the plants. After 30 days under water deficiency the plants were rehydrated and the evaluations performed again. At 200 DAP the biomass evaluation was carried out. In this experiment, the same analytical procedures used in the first experimental stage were adopted. In the first test, SP06, SP09 and SP10 showed the best physiological, biometric and biomass accumulation responses when compared to non - regenerated plants in vitro. In the second test, the genotypes of the cultivar SP803280 that experienced the water stress situation in the previous generation showed a greater tolerance to water deficit when exposed to this second stress, indicating induction of phenotypic changes, probably through mechanisms epigenetics. The somaclonal variation proved to be a good tool in obtaining plants that are more tolerant to water deficit. Thus, it is possible to conclude that the water deficit applied in the first clonal generation of sugarcane plants acted as a plant priming process, increasing the adaptive potential of the plants in the subsequent generation.