Emergência de plântulas e caracterização de Inajá em Roraima, Amazônia, Brasil

Abstract

Maximiliana maripa (Aublet) Drude, popularly known as inajá, is a native Amazonian palm tree that spreads through seeds, commonly found in antropized areas of northern Amazonia, with great productive potential for the food, pharmaceutical, cosmetics and biofuels industries. This work is divided into three chapters where first we evaluated the emergency of inajá seedlings subjected to different environments and substrates in nursery conditions. In the second approach we observed the influence of the storage time and environment in the emergence of seedling and finally, we characterized matrices and the seedlings morphology individuals belonging to the inajá Active Germosplasm Bank (BAG-inajá) of Embrapa-RR. We conducted the seedling emergence experiments at Embrapa headquarters in Boa Vista-RR, with material collected from a inajazal located in the Experimental Station Serra da Prata, belonging to Embrapa-RR in the municipality of Mucajaí, Roraima state. The experimental design used for emergency tests on different substrates and environments was a randomized block with four replications of 20 pyrenes, following a 3x3 factorial scheme, with three substrates (sand, sawdust and sand + sawdust) and three environments (full sun, greenhouse and shading). For storage tests, after harvesting a part of the batch of fruits was processed and directed for immediate planting and the remainder acondicioned in polyethylene bags and stored at cold chamber at 18 °C. The experimental design was a randomized block in a 5x2 factorial scheme, with 5 storage times (0, 30, 60, 90 and 120 days) and 2 sowing environments (greenhouse and full sun), with four replicates of 20 pyrenes per plot. Station belonging to Embrapa-RR in the municipality of Mucajaí, Roraima state. We determined the water content of the seeds gravimetrically (105 ° C for 72 hours) using four replicates of 10 seeds. This procedure was performed both immediate planting seeds and those stored, at the end of the period for the treatment of storage. In both experiments, the inajá pyrenes were planted in beds to two inches deep in a horizontal position, with the temperature and humidity of environments measured with the use of a thermohygrometer SH 122 model. We also evaluated the frequency, speed index and the average time of emergence of inajá seedlings. For the matrices characterization studies, morphometric data were collected of 70 individuals belonging to BAG-inajá Embrapa-RR, derived from natural regeneration and randomly distributed in silvopastoral systems in the of Alto Alegre, Boa Vista, Cantá, Caracaraí, Iracema and Mucajaí municipalities. For the seedlings morphological description we used seedlings sown in beds containing sand, after the complete settlement of the same. In the emergency tests, there were significant differences between the environments and the substrates tested with the frequency and significantly higher speed of emergence index in the sand substrate in both full sun and greenhouse tests. We obtained the best results of emergence with immediate planting in greenhouse environment and sand substrate, where the germination percentage was 100%. The storage in cold chamber maintained seed moisture content and possible seedling emergence in tests in a greenhouse up to 120 days of storage, however, did not achieve the percentages acquired in immediate planting. In the caracterization studies, we identified and described three different Maximiliana maripa morphotypes based on the insertion leaves on the stem: columnar leaf insertion (M1 morphotype), semiespiralada leaf insertion (M2 morphotype) and spiral leaf insertion (M3 morphotype). For each morphotype we quantified the number of sheets, bunches producing, matrices DAP and we made the morphometric analysis of fruits and morphometric caracterization of seedlings. The M2 morphotype showed the highest values for the most analyzed parameters, especially in relation to fruit diameter, fruit and pyrenes weight. The most frequent inflorescences amongst the studied morphotypes showed to be predominantly female, androgynous and predominantly male inflorescences were also found along with more than one type of inflorescence per individual. We found no statistically significant differences in the average production of bunches between the three morphotypes There is great variability in relation to fruit coloration, regardless of origin. Probably the semi spiralate morphotype (M2) is an intermediate form of a very variable character in M. maripa. Seedlings of Maximiliana maripa did not show typical characteristics described for Atallea genus.