ABSTRACT
Rhipsalis paradoxa, Rhipsalis baccifera and Hatiora salicornioides are epiphytic cacti from the Atlantic Forest. They have a great ornamental potential due to the exotic characteristic of their joints (stems segments). The study aimed to evaluate the growth and development of roots and shoots as well as macronutrient and micronutrient contents in the joints of these species fertilized with different concentrations of urea as a nitrogen source. The study also analyzed the importance of the root system on nitrogen absorption. Plants were weekly irrigated with modified Hoagland & Arnon solutions with 0, 16.7, 33.3, 49.9 or 66.6 mM N applied as urea. After 180 days of cultivation, plants were separated into joints and roots for biometric and biomass measures, as well as macronutrient and micronutrient analysis of joints. The experimental design was randomized blocks, with five treatments, four blocks and five plants per plot, for each species. Data were submitted to analyses of variance and regression. R. baccifera showed the highest plant length and number of joints in 29.94 and 40.82 mM N, respectively, H. salicornioides showed the highest length and number of joints in 48.29 and 45.68 mM N respectively. For R. paradoxa, the highest length was in 66.6 mM N. The lowest values for plant length and number of joints were observed in the absence of N, for all species. High nitrogen concentrations in the solution increased the N concentration in joints of R. baccifera, R. paradoxa and H. salicornioides by 24, 19 and 13 g N/kg dry mass, respectively. The roots of epiphytic cacti, besides the function of fixing the plant on substrate (phorophyte), are functional for nutrient absorption, and the best results were obtained in 30.05 to 66.60 mM N in the nutrient solution.
Keywords:
Rhipsalis paradoxa; Rhipsalis baccifera; Hatiora salicornioides; nitrogen fertilization; stems and roots; nutrient levels.
Thumbnail
Thumbnail
