Aspectos do metabolismo de plantas de crambe (Crambe abyssinica) submetidas a diferentes doses de nitrogênio visando a produção de óleo para biodiesel

Abstract

The crisis and projections around the petroleum business, lead a growning necessity to the development of alternatives energy sources. In this context, biofuel are characterized as a major alternative energy source and, between the countries with great potencial for its production, Brasil plays a role due to its possibilities in agroenergy. This is explained by the big availability of workforce and cultivation area, besides, its high vegetal diversity. However, the agroenergy development can leads some deviation of food production, since the principal cultures used for this, are soybean, corn, sugarcane, sunflower and oilseed rape. In this way, the development of the potential of cultures that are not employed for food industry is very important. Crambe (Crambe abyssinica) shows a high potential for the biodiesel industry, due to its precocity (can be harvested around 90 days), elevated productivity (1000 and 1500 kg/ha), low production cost, and a percentage of total oil around 26 and 38%. Moreover, crambe is toxic for human feeding and therefore, do not compete directaly with the food industry. On the other hand, though this culture shows a great potential, there is a few informations about its production, whereas do not exist a cultivation guideline established. In this way, researches that aim enhance its production with lower costs and so the environmental impacts, are immensely relevants. The aim of this work, was to evaluate the outcome of distincts nitrogen doses on vegetal metabolism, because of, the already known, influence of this nutrient in cultures productivity and for represent a significative portion in costs involved in agricultural production. Thereby, crambe were cultivated in nutritive solution with differents nitrogen doses (T1= 1, T2= 2,5, T3= 5 and T4= 7,5 mM of N-NO3 -) in greenhouse. Each treatment was compound of 3 repetitions and during the experiment were done 2 harvests, the first one in the beginning of the flowering and the other one, in the end of the seed production (68 and 103 days after germination, respectively). The experimental design used was completely randomized desing fatorial arrangement 4 x 2 (Tre x Har). Among the obtained results, is interesting to emphasize, that there was not significative influence of the differents nitrogen doses on the seed production. Further, the treatment with the lower nitrogen dose (T1= 1mM of N-NO3 -) was efficient, since it enabled the obtainment of a high oil yield, comparing with the others treatments. Thereby, the results obtained in hydroponic culture indicates availability in the use of this dose for crambe cultivation, since it represents a improvement for its cultivation and decrease the costs and envirommental impacts.