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rESUMENSe evaluó la germinación y supervivencia in situ y ex situ de plántulas de Aspidosperma megalocarpon, Eugenia sp., Lonchocarpus castilloi, Manilkara zapota, Ormosia macrocalyx y Rollinia mucosa. En campo se sembraron 2 160 semillas en nueve bloques de 5 m x 20 m distribuidos en bosque tropical, acahual maduro y acahual joven. El experimento se replicó en condiciones de vivero bajo sombra de 40, 60 y 80%. Los tipos de cobertura vegetal no mostraron diferencias significativas en las tasas de germinación y de crecimiento; sin embargo, estos sí influyeron en la capacidad de germinación de A. megalocarpon y O. macrocalyx, y en las tasas de depredación de M. zapota y L. castilloi. En el acahual joven se presentó la mayor depredación de semillas, sin embargo, las plán-tulas remanentes presentaron mayor supervivencia que en las otras coberturas vegetales. En el vivero no se encontró diferencia en la proporción de semillas germinadas, ni en las tasas de germinación y de crecimiento. R. mucosa, fue la única especie que presentó menor supervivencia (42%). Las condiciones ambientales de las diferentes clases de cobertura vegetal en el área de estudio mantienen condiciones adecuadas para el proceso de germinación, crecimiento y establecimiento de plántulas de las especies estudiadas, lo cual permite sugerir su utilización en la rehabilitación de áreas degradadas del bosque original sembrando de manera directa, siempre y cuando se realice de manera inmediata después de la recolecta. Es necesario continuar con estos estudios para promover el uso de especies nativas en la rehabilitación y restauración de bosques tropicales. PALABRAS CLAVE:Condiciones ambientales, depredación, establecimiento, semillas de árboles, tasa de crecimiento, tasas de germinación. ABSTrACTWe evaluated the germination and survival in situ and ex situ of seedlings of Aspidosperma megalocarpon, Eugenia sp., Lonchocarpus castilloi, Manilkara zapota, Ormosia macrocalyx and Rollinia mucosa. We established nine blocks of 5 m x 20 m in the field, in which 360 seeds of each species were established in three successional conditions with three repetitions: mature tropical forest, advanced fallows and young fallows. The experiment was replied in a tree nursery using 40, 60 and

Aim of study: The objective of this study was to present statistical information pertaining to recurrent inconsistencies found in the literature of the last 25 years that involve calculation of the GR and the errors that this may entail when interpreting the seed vigor of different botanical materials.Materiales y métodos: After filtering articles that did not present numerical results or in which the application of Maguire's formula was not clearly indicated, a total of 124 papers were ultimately used in this study.Main results: Germination rate (GR) represents the potential of seeds to germinate and, along with germination percentage (GP), are the two most important measurements when evaluating seed quality. The correct calculation of GR allows the seeds classification according to their vigor and capacity to produce healthy seedlings, so it is very important to rely on the adequate mathematical formula for this purpose. According to the formula developed by Maguire, this parameter is calculated by the sum of values obtained when dividing the GP at different times (i.e. daily) by the total time elapsed since the start of the test. We have found from the relevant literature that different authors have been using different ways of applying the formula, which makes it difficult to directly compare the results.Research highlights: A total of 54.8 % of the papers reviewed, belonging mainly to the theme of forestry, presented objectionable application of the formula. Publication of this warning may help to reduce the occurrence of this situation in the future.Keywords. Germination percentage, germination speed, Maguire’s formula, seed vigor.

Background: Ormosia macrocalyx is a tropical forest tree classified as endangered. Its seeds experience problems of dispersion and apparent physical dormancy due to their hard seed coating. Hypotheses: 1) The stages of dehiscence of the fruits of Ormosia macrocalyx influence the germinative behavior of its seeds. 2) Pregerminative treatments will improve the germination process of the seeds stored under refrigeration. Study species: Ormosia macrocalyx Study site and period: Villahermosa, Tabasco, Mexico from October 2012 to October 2014 Methods: Two completely randomized experiments were conducted in order to analyze the germination process by 1) evaluating germination in seeds from fruit at three stages of dehiscence (closed, semi-open, and open fruit) and 2) applying four treatments, including three pregerminative treatments (water soaking for 24 h, mechanical scarification and scarification+1% gibberellic acid) plus an untreated control, to seeds stored under refrigeration for 17 months. Results: Differences were found in germination rate (GR), corrected germination rate (CGR) and time to attain 50 % germination (T 50 ) among treatments in the first experiment, with the seeds from open fruits presenting the lowest response (3.31 % day -1 for GR and CGR, and 15.8 days for T 50 ), although all treatments showed similar times for the initiation of germination (GI) and final germination percentage (GP). In the second experiment, the effect of scarification was greater than both the control and soaking treatments. Scarification treatment values were 68.0 % (GP), 12.0 days (GI), 4.53 % day -1 (GR), 6.65 (CGR) and 14.5 days (T 50 ). Addition of gibberellic acid did not produce any further advantage over scarification alone. Conclusions:Seeds from open fruits have lower germination rates, although the final GP is not affected. Stored seeds present physical dormancy but lose viability with storage and, when collected after remaining attached to the tree for undefined periods, scarification can greatly improve their germination rate. Key words: fruit maturation, dormancy, pregerminative treatments, storage Germinación de semillas de Ormosia macrocalyx, un árbol forestal amenazado ResumenAntecedentes: Ormosia macrocalyx es un árbol tropical amenazado. Sus semillas tienen problemas de dispersión y aparente latencia física por cubierta seminal dura. Hipótesis: 1) Las etapas de dehiscencia de los frutos de Ormosia macrocalyx repercutirán en el comportamiento germinativo de sus semillas. 2) Los tratamientos pregerminativos mejorarán el proceso germinativo de las semillas almacenadas en refrigeración Especie de estudio: Ormosia macrocalyx Ducke. Sitio de estudio y fechas: Villahermosa, Tabasco, México, octubre 2012-octubre 2014 Métodos: Se establecieron dos experimentos completamente aleatorios para analizar el proceso de la germinación: 1) Evaluación de la germinación en semillas de frutos en tres estados de madurez (cerrados, semi-abiertos y abiertos), y 2) Aplicación de cuatro tratamientos, tres pregerminativos (r...