LAUSR

Myracrodruon urundeuva Fr. All.is a tree belonging to the family Anacardiaceae, popularly known as ‘aroeira-do-sertao’, which has potential for wood production and medicinal purposes but it is threatened with extinction. This work investigated the callogenesis of the species and biochemically analyzed the calli produced, aiming at further studies of somatic embryogenesis. Leaf explants were inoculated in MS culture medium (Murashige and Skoog, 1962) supplemented with different concentrations of 2,4-dichlorophenoxyacetic acid (0.0, 2.5, 10.0 and 20.0 μM), kinetin (0.0, 2.5 and 5.0 μM) and glutamine (0.0, 0.34, 0.68 and 1.37 μM). For the growth curve, the fresh mass of explants with and without calli was determined until the 56 th day of culture, at intervals of 7 days. Reducing sugars (RS), sucrose and total soluble sugars (TSS) were measured at each growth curve period. The use of 2,4-D was efficient for callus induction in Myracrodruon urundeuva , and callogenesis was enhanced with the combination of 2,4-D, KIN and glutamine in the nutrient medium. The growth curve of the calli presented sigmoidal shape with five distinct phases: lag, exponential, linear, deceleration and stationary. The content of sucrose and TSS presented different behavior according to the different stages of callus growth, exhibiting accumulation of sugars in the period of preparation for growth, degradation in the exponential phase and once again accumulated these carbohydrates in the final stages (deceleration and stationary). The RS content, except day zero, remained stable during all evaluated periods. The calli of Myracrodruon urundeuva have embryogenic potential, but further studies are suggested to obtain somatic embryos, as well as to identify the period in which they are formed.