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Boa Vista, Brazil

This work was carried out in order to study the phenological pattern of brasil-nut trees in natural forest located in the south of Roraima state, in order to relate the frequency of occurrence of phenophases with rainfall. For the phenological survey 20 adult trees (DBH > 50 cm) were selected in a permanent sample plot of 9 ha. The phenological observations occurred fortnightly from February 2006 to February 2009, when data were collected on the presence or absence of events of flowering, fruiting, leaf flushing and leaf fall for each tree. The Index of population synchrony was used for estimating the synchrony of phenological events. The flowering of brasil-nut proved to be regular, annual, long and synchronous and was correlated with the reduction of rainfall. The fruiting was regular and synchronous, and dispersal was correlated with rainfall reduction. The phenological pattern of leaf flushing tended to vary yearly, being around the continual one in 2007 and bimodal in 2006 and 2008. It was noticed a higher proportion of trees falling leaves between August and October which characterizes a period of transition between the dry and the rainy time with sensitive reduction of rainfall. Source

Smiderle O.J.,Embrapa Roraima | Schwengber L.A.M.,Federal University of Roraima
Revista Brasileira de Sementes | Year: 2011

Dormancy is a phenomenon in which seeds of a species do not germinate, even when they are viable and environmental conditions are suitable. The objective of this study was to assess the effects on seeds of different periods of immersion in boiling water, with or without posterior immersion in sodium hypochlorite, on the alleviation of paricarana (Bowdichia virgilioides Kunth.) seed dormancy. Seeds were previously homogenized and separated according to size and color, with red-colored seeds being used. The treatments applied were: T1 = immersion in water at 100 °C for one second; T2 = immersion in water at 100 °C for 10 seconds; T3 = T2 + posterior immersion in 2.5% sodium hypochlorite for 1 minute; T4 = immersion in water at 100 °C for 20 seconds; T5 = T4 + immersion in 2.5% sodium hypochlorite for 1 minute. Each treatment consisted of four replicates of 50 seeds. The highest emergence scores were obtained with seed immersion in water at 100 °C for 10 seconds, with or without the posterior use of sodium hypochlorite. This is the recommended procedure for breaking the seed tegument dormancy of paricarana (B. virgilioides). Immersion of paricarana seeds in sodium hypochlorite for one minute, after seed immersion in water, facilitates imbibition and reduces seed deterioration. Source

Smiderle O.J.,Embrapa Roraima | Das Gracas Souza A.,Federal University of Pelotas
Revista Brasileirade Ciencias Agrarias | Year: 2016

Brazil imports great amounts of C. zeylanicum from different countries, both barks and essential oil, given the absence of commercial cultivation of this spice in the country. Hence, due to the need of studying and indicating adequate mineral fertilizers in the production of C. zeylanicum seedlings, this work intended to investigate the effect of adding different concentrations of the complete nutrient solution in the production of high-quality seedlings with potential for commercial purposes. The experimental design used was completely randomized in the split-plot scheme and ten evaluations. In the plots, we evaluated the effect of the concentrations (T1 - 0%, T2 - 25%; T3 - 50%; T4 - 75%; T5 - 100%) of the nutrient solution during the growth period and in the subplots, the evaluation periods was evaluated monthly. Both growth characteristics (height, stem diameter and dry matter of shoots and roots) and quality parameters of the seedlings (Dickson index) was assessed. The nutrient solution at the concentration of 75% provides height and stem diameter growth and increased indices of Dickson quality, shoot dry matter, root dry matter and total dry matter, being suitable for the production of C. zeylanicum seedlings. C. zeylanicum seedlings have low nutrient requirements; thus, the concentration of 100% of the nutrient solution characterizes luxury consumption. Source

Costa N.D.L.,Federal University of Parana | Gianluppi V.,Embrapa Roraima | De Moraes A.,Federal University of Parana
Ciencia Animal Brasileira | Year: 2012

The effects of plant regrowth age (21, 28, 35, 42, 49, 56, 63 and 70 days) on dry matter (DM) yield, and morphogenetic and structural characteristics of Trachypogon vestitus, submitted to burning, during dry season, were evaluated under natural field conditions. The experimental design was completely randomized, with three replications. Evaluations were carried out during the period from December 2009 to February 2010. DM yields, absolute growth rate, number of tillers/plant (NTP), number of leafs/plant (NLP), leaf area, leaf senescence and elongation rates and blade length (BL) increased consistently with growth stage (P<.05). The relations among DM yield, forage production rate, NTP, NLP and BL with plants regrowth age were described by the quadratic regression model and the maximum values were estimated at 64.8; 42.3; 59.6; 61,8 and 59.4 days of regrowth, respectively. The crop growth and relative growth rates, tiller and leaf appearance rates were inversely proportional to plant age.KEYWORDS: dry matter; leaves; morphogenesis; plant age; tillering. Source

Barbosa R.I.,INPA Nucleo de Pesquisas de Roraima | Junior M.M.,Embrapa Amazonia Oriental | Luz F.J.F.,Embrapa Roraima
Horticultura Brasileira | Year: 2010

Our objective was to study distinctions in the morphology of the pepper fruits (Capsicum spp., Solanaceae) used by indigenous (living in traditional villages) and non-indigenous groups (originated from migration and colonization, with or without miscegenation, living on non-indigenous lands) in the State of Roraima, Northern Brazilian Amazonia. In this sense, we used a database with 182 subsamples of Capsicum spp. Accessions were collected at 39 sites (14 indigenous and 25 non-indigenous), which were characterized additionally in relation to the predominant phytophysiognomy (savanna or forest) and home zone (rural or urban). We found morphological differences in pepper fruits related to both phytophysiognomy and home zone of the collecting site, but not to ethnical origin. We believe those differences are more related to the inherent crop practices, which suffer strong environmental influence, than to user preference. Both indigenous and non-indigenous groups preferred morphotypes from C. chinense and C. frutescens, which have small and highly pungent fruits. Nevertheless, fruit color was not important. These morphotypes are used by both indigenous and non-indigenous users for preparing sauce and jiquitaia (pepper powder). We suggested 'cultural adherence' as the reason for the common preferred use of peppers by both ethnical groups analyzed in Roraima. Source

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