Germinação de sementes e produção de mudas de Guariúba (Clarisia racemosa Ruiz et Pavon) - Moraceae

Abstract

Clarisia racemosa Ruiz et Pavon (guariúba) of the family Moraceae, is a native tree in the Amazon region which is used commercially as timber in the local market and also for exportation. The seeds of guariúba are recalcitrant and germinate immediately after they are dispersed or collected, this way, the identification of the substrate most adequate for germination and production of seedlings is made with quality is important. The objective of this study was to avaliate the influence of different substrates in the germination and production of seedlings of guariúba in two cultivative environments. The experiment was conducted in a nursery and inside a asa de vegetação (house of vegetation) of the Faculty of Agrarian Sciences of the Federal University of Amazonas UFAM. The seeds were extracted manually form matured fruits sown in flowerbeds covered with a 50% sombrite screen. The substrates tested for the germination of seeds were washed sand, a medium granulometria vermiculite , sawdust, sawdust + sand (1:1) and humus ( 0 - 20 cm layer of forest soil). A delineamento experitental inteiramente casualizado (DIC) (experimental delineation completely casualized) with five treatments and four repetitions of 25 seeds was used. The criterion for germination was the emergence of the caulicle above the substrate, considering normal, the plantule with total coverage of the eofilo . The avaliations were made on daily basis considering the average time for germination in days (TM), the percentage of germination (% G) and the index of velocity of emergence (IVE). The items used were subsoil + sand 3:1 (T+Ar), subsoil + sand + cowdung 3:1:1 (Ts+Ar+Eg), subsoil + sand + cowdung + organic compost 3:1:0,5:0,5 (Ts+Ar+Eg+Co), subsoil + sand + organic compost 3:1:1 (Ts+Ar+Co) and one fraction forest soil (Sf), in a completely casualized delineament (DIC), with five treatments and three repetitions, with three plants in a factorial scheme, with two environmental factors (nursery and house of vegetation) and five compositions of substrates. The growth analyses avaliated within the periods of 30, 60, 90 and 120 days after the transplanting were height (ALT altura ), neck diameter (DC diametro de colo ), number of leaves (NF número de folhas ), and at 120 days also, a destructive collection was made in order to obtain of leaf area (AF) the weight of dry material of the airy part (PMSPA), weight of dry material of the radicular system (PSR), the relation airy part/ radicular system (RPAR). The fruits presented in medium, length of 33,29 mm and weight of 6,712 g. The seeds presented length of 24,61mm and weight of 2,83g. The results of the analyses of the variables studied for the germination did not present significant differences between the substrates tested with average germination of 90% starting from the 30th day and ending on the 45th day after planting. The substrates, forest soil, subsoil + sand + cowdung and subsoil +sand + cowdung + organic compost proportioned the best growths in all the variables, with the exception of the relation PMSPA/PSR. The nutrient teors on the leaves followed the decreasing order of N>K>Ca>Mg>P. The environment, house of vegetation, proportioned the best results in all the variables compared to the nursery with the exception of the RPAR.