Germinación y emergencia de plántulas de cuatro especies de encino amenazadas

Abstract

Germination and emergence of the endangered cloud forest oak species Quercus germana, Q. insignis, Q. sartorii and Q. xalapensis were observed under different light conditions (sun vs. shade) in a secondary forest fragment (SFF) and in a greenhouse (GRE). Seed weight variability was evaluated for each species and its relationship to germination and emergence determined. After 60 days, a total of 62.17% of the acorns had germinated and 37.79% had emerged in both experiments. Germination was highest in Q. sartorii (71.83% ± 2.09%), followed by Q. germana (66.33% ± 2.06%), Q. insignis (60.83% ± 2.34%) and Q. xalapensis (53.50% ± 2.32%). In the GRE, Q. insignis germination was higher under sun (62.00% ± 4.73%) than shade (48.00% ± 5.12%), whereas its emergence was the lowest (37.66% ± 3.46%) compared to other species in both light environments. In the SFF, germination and emergence only differed among species; Q. xalapensis germination was lowest (47.00% ± 3.11%) and Q. sartorii emergence was highest (58.66% ± 3.35%), compared to the other species. Acorn weight did not influence germination or emergence in any species. The implications of this study are discussed, along with recommended propagation techniques for growing oaks for forest restoration in disturbed areas.Keywords: early seedling establishment, light environment, Quercus, seed mass, tropical montane cloud forest.resumen La germinación y emergencia de encinos amenazados del bosque de niebla, Quercus germana, Q. insignis, Q. sartorii y Q. xalapensis fue evaluada bajo diferentes condiciones lumínicas (sol vs. sombra) en un fragmento de bosque secundario (SFF) y un invernadero (GRE). Para cada una de las especies, la variabilidad del peso de la semilla fue relacionada con la germinación y emergencia. Después de 60 días, en ambos experimentos, un total de 62.17% de las bellotas germinaron y 37.79% emergieron. La germinación fue mayor en Q. sartorii (71.83% ± 2.09%), seguido de Q. germana (66.33% ± 2.06%), Q. insignis (60.83% ± 2.34%) y Q. xalapensis (53.50% ± 2.32%). En el GRE, la germinación de Q. insignis fue mayor bajo el sol (62.00% ± 4.73%) que bajo la sombra (48.00% ± 5.12%), mientras que su emergencia fue la más baja (37.66% ± 3.46%) comparada con otras especies en ambos ambientes lumínicos. En el SFF, la germinación y emergencia solo fueron diferentes entre especies; Q. xalapensis registró la germinación más baja (47.00% ± 3.11%) y Q. sartorii la emergencia más alta (58.66% ± 3.35%) comparada con el resto de las especies. El peso de la bellota no influyó en la germinación y emergencia de las especies. Se discuten las implicaciones de este estudio, así como recomendaciones sobre técnicas de propagación para la producción de encinos para restaurar bosques en áreas perturbadas.Palabras clave: establecimiento temprano de plántulas, ambiente lumínico, Quercus, peso de semilla, bosque de niebla.

The Effect of Seed Size on Germination and Seedling Growth in Sweet Chestnut (Castanea sativa Mill.)

“…Although the data for sweet chestnut is limited, the connection between seed size, germination rate and survival has been well-studied in another Fagaceae genus, i.e., oak (Quercus L.). Our results are in accordance with Alptekin and Tilki [38] and Garcia-De La Cruz et al [39], who concluded that seed size did not affect the acorn germination rate or seedling emergence of the four analyzed oak species. On the other hand, Purohit et al [40] and Pandey et al [41] described a positive relationship between seed size and germination rate in oaks.…”

“…Similar positive correlations between seed mass and germination rate were documented in other plant species [42][43][44][45][46]. These different results, even within the same genus, can possibly be explained as a species-specific reaction to the environmental conditions, variation in maternal origin, differences in provenance and intraspecific variation within a larger range of a species [39,47]. However, storage and proper stratification prior to sowing can also influence the germination and subsequent development of seedlings [32].…”