ABSTRACT
The use of native tree species for restoration of degraded areas is often hindered by the lack of information about the nutritional requirements of seedlings at the nursery stage. Therefore, this study aimed to evaluate the growth and morphological responses of Handroanthus impetiginosus seedlings to mineral nitrogen fertilization. The experiment was carried out from July to October 2013 in a seedling nursery under 50% shade cloth. Seeds were germinated for 15 days in low density polystyrene trays and then transplanted into 0.9-L polyethylene plastic bags. A complete randomized block design was used, with four replications and four plants per experimental unit. Treatments consisted of five nitrogen levels (0, 50, 150, 300 and 450 mg N dm-3), using ammonium sulfate as the nitrogen source. Two months after transplanting, the following variables were assessed: leaf chlorophyll content; leaf area; specific leaf area; leaf area ratio; root, stem, leaf and total dry mass; shoot dry mass/root dry mass ratio; shoot height/shoot dry mass ratio; and Dickson quality index. Mineral nitrogen fertilization improved seedling growth by promoting higher results of the leaf chlorophyll content, leaf area and shoot dry mass production. Thus, fertilized seedlings significantly expanded their leaves and invested more in shoot growth, improving their hardiness and quality. The nitrogen level of 240 mg dm-3 was considered to be the most effective for production of H. impetiginosus seedlings.
O uso de espécies arbóreas nativas para restauração de áreas degradadas é muitas vezes prejudicada pela falta de informação sobre os requerimentos nutricionais de mudas na fase de viveiro. Portanto, este trabalho objetivou avaliar o crescimento e respostas morfológicas de mudas de ipê-roxo à adubação mineral nitrogenada. O experimento foi conduzido de julho a outubro de 2013, em viveiro de mudas com tela de sombreamento de 50%. As sementes foram postas para germinar por 15 dias em bandejas de poliestireno de baixa densidade, e posteriormente transplantadas para sacos plásticos de polietileno de 0,9 L. Foi utilizado o delineamento de blocos completos ao acaso, com quatro repetições e quatro plantas por unidade experimental. Os tratamentos foram constituídos por cinco níveis de nitrogênio (0, 50, 150, 300 e 450 mg N dm-3), utilizando o sulfato de amônio como fonte. Dois meses após o transplantio, as seguintes variáveis foram avaliadas: conteúdo de clorofila foliar; área foliar; área foliar específica; razão de área foliar; matéria seca da raiz, caule, folhas e total; relação massa seca da parte aérea/massa seca da raiz; relação altura/massa seca da parte aérea; e índice de qualidade de Dickson. A adubação mineral nitrogenada otimizou o crescimento das mudas ao promover resultados mais elevados para o teor de clorofila, área foliar e produção de massa seca da parte aérea. Assim, mudas adubadas expandiram significativamente suas folhas e investiram mais no crescimento da parte aérea, melhorando sua rusticidade e qualidade. O nível de nitrogênio de 240 mg dm-3 foi considerado o mais eficiente para produção de mudas de ipê-roxo.
Subject(s)
Conservation of Natural Resources , Tabebuia/growth & development , Environmental Restoration and Remediation , NitrogenABSTRACT
We evaluated the effect of soil "scarification" and vegetation clearing treatments on the natural regeneration and initial development of Tabebuia rosea (Bertold) DC. seedlings in a moderate sized semideciduous tropical forest subjected to wood harvesting on the coast of Jalisco, Mexico. The treatments were applied under "seed" trees, and the number of germinated seedlings and their development were evaluated for nine months. Soil "scarification" promoted seed germination and initial seedling development, while the control of the competing vegetation increased the seedling growth and reduced their mortality. These results should be taken into account for the natural regeneration of this species, after clearing, to improve wood production, and should be incorporated into the silvicultural techniques currently developed in the region.
Evaluamos el efecto de los tratamientos de remoción de suelo y roza de vegetación sobre el establecimiento y desarrollo inicial de la regeneración natural de Tabebuia rosea (Bertold) DC. en una selva mediana subcaducifolia sometida a aprovechamiento maderable en la costa de Jalisco, México. Los tratamientos se aplicaron bajo la copa de árboles semilleros y se evaluó el número de plántulas emergidas y su desarrollo durante nueve meses. El tratamiento de remoción de suelo favoreció la emergencia de plántulas y su desarrollo inicial, mientras que el control de la vegetación competidora promovió un mayor crecimiento y menores porcentajes de mortalidad. Estos aspectos deben tomarse en cuenta para la regeneración natural de la especie después de la aplicación de las cortas con fines de aprovechamiento maderable y se sugiere incorporarlos a las técnicas silvícolas que actualmente se desarrollan en la zona.
Subject(s)
Tropical Climate , Seedlings/physiology , Soil , Tabebuia/physiology , Trees , Mexico , Seedlings/growth & development , Tabebuia/growth & developmentABSTRACT
El presente trabajo tuvo por objetivo multiplicar y mantener in vitro plantas de Tabebuia rosea y de Cordia alliodora, a partir de semillas de cinco árboles plus de la primera especie y uno de la segunda. A partir de este material se seleccionaron plantas núcleo (PN), Yemas apicales de las plantas núcleo obtenidas, fueron removidas y cultivadas bajo condiciones in vitro hasta producir 1480 plantas de las dos especies. El proceso de aclimatización del material vegetal se llevó a cabo bajo condiciones de invernadero, en cámaras húmedas ubicadas en la estación experimental "Bambusa" en Pacho, Cundinamarca. Para el manejo de la información, se diseñó una base de datos en el programa Access, Microsoft Office®, con el fin de monitorear y evaluar el comportamiento de cada uno de los individuos durante el desarrollo in vitro, por medio del cálculo de tasas de velocidad de multiplicación (TVM), tasa de pérdida (TP) y tasa de eficiencia del proceso (TE). Este material será entregado a Conif para el establecimiento de la primera plantación de origen in vitro, que será utilizada posteriormente para ensayos de propagación vegetativa, análisis de pruebas clonales y moleculares.
This work was aimed at multiplying and maintaining in vitro plants from seedlings from five Tabebuia rosea (large spreading cedar tree) from and one Cordia alliodora (walnut tree used for providing shade for coffee plantations). Apical leaf buds were excised from mother plants (MP) and cultured in vitro until 1480 plants had been produced from the two species. The hardening process was carried out in greenhouse conditions using humid flow-chambers at Geoambiente Ltdas Bambusa experimental station in Pacho, Cundinamarca. A database was created using Microsoft Office Access software for handling information required for monitoring and evaluating each plants behaviour during the in vitro culture process by calculating the rates of multiplication (RM) and loss(RL). The plants so produced will be used by Conif for field trials and evaluation purposes. This material will then be multiplied by vegetative propagation and used for clone and molecular testing analysis.