Effect of pre-germinative treatments on <i>Nothofagus glauca</i> seed germination and seedling growth

Abstract

Background: Nothofagus glauca (Phil.) Krasser (Nothofagaceae, “Hualo”) is an endemic tree of the Mediterranean zone of Chile. The natural forests in this area have been severely fragmented as a result of human causes such as replacement by agricultural crops and fast-growing tree species. From 1975, these forests have declined from 900,000 ha to 145,000 ha, so it is categorised on the IUCN Red List as ‘vulnerable’. In restoring this ecosystem, efforts should focus, in part, on the propagation of quality stock. However, information on propagation systems is still insufficient.&#x0D; Methods: We aimed to analyse the effect of different pre-germinative treatments and sowing times on seed germination, and seedling growth and quality. The pre-germinative treatments were: (i) cold stratification; (ii) soaking in gibberellic acid (GA3) and thiourea solution; and (iii) nursery cultivation, while the sowing times were July, August and September.&#x0D; Results: A high germination capacity was achieved by: soaking the seeds in GA3 solution irrespective of concentration; stratifying, irrespective of period; or soaking in 7.5 mg L-1 thiourea solution, values significantly varied from that of the control treatments. The sowing time was not relevant in terms of the percentage of germination or seedling development. Stratification at 5°C for 60 days produced the best quality indices for N. glauca seedlings but no significant differences were found in any of the morphological attributes tested as a result of the pre-germinative treatments.&#x0D; Conclusions: The pre-germinative treatments significantly improved the germination and seedlings growth of N. glauca. Cold stratification at 5°C for 60 days is recommended as it produced suitable seedlings for field establishment. Gibberellic acid and thiourea did not produce important effects on seedling growth. Our results suggest the presence of endogenous physiological dormancy of the N. glauca seeds. The results of this study provide important information on propagation and nursery techniques of N. glauca, which can be used in restoration programmes.

Effect of Temperature on the Germination of Five Coastal Provenances of Nothofagus glauca (Phil.) Krasser, the Most Representative Species of the Mediterranean Forests of South America

“…This same trend is also observed in both the average germination speed and vigor, meaning that the germination process of N. glauca is strongly conditioned by temperature. The germination ratio at the optimal temperature (i.e., 22 °C), is in the range found by other authors for the same species [ 12 , 13 ].…”

“…In addition, the dimerous seeds were measured for length and width, and the trimerous seeds for length, width, and thickness ( Table 2 ). To break the dormancy, the seeds were soaked in a 200 mg L −1 gibberellic acid solution (Giberplus ® Tabletas, Anasac Chile S.A., Santiago, Chile) for 24 h before starting the germination tests [ 12 ].…”

“…N. glauca is a species whose seed production cycles are becoming longer, with years without seed production (unpublished data) and has seeds that present endogenous dormancy. There are mechanisms to break this condition, for example, through variable stratification periods at 4 °C (i.e., between 4 and 6 weeks) or by soaking them in gibberellic acid in concentrations from 0.1 to 0.8 g L −1 [ 12 ], reaching a germination ratio even above 95% using only viable seeds. However, the germination percentage may be different depending on the origin of the seeds [ 13 ].…”

SEEDLING EMERGENCY AND BIOMETRY OF FRUITS AND SEEDS OF Cariniana pyriformis FROM THE MIDDLE MAGDALENA VALLEY, COLOMBIA

“…According to the classification described by Baskin and Baskin (2004) and based on the fact that there was permeability in the seed cover to the phytoregulator, it is suggested with the current study that a certain amount of abarco seeds might have seeds might have non-deep physiological dormancy: GA 3 promotes germination. Further, other separate or combined pregerminative treatments, such as warm moist stratification or alternation of temperatures to break dormancy in abarco, should be evaluated because these treatments have proven to be effective with this type of dormancy in other forestry species (Pipinis et al, 2014;Cabello et al, 2019).…”

Germinación de semillas de Quercus humboldtii Bonpl. (Fagaceae): especie vulnerable del bosque Altoandino

“…Las giberelinas, entre estas el ácido giberélico (GA3), son reguladores del crecimiento vegetal, los cuales se emplean para promover, acelerar y uniformizar el proceso de germinación en especies forestales (Cabello et al, 2019). Aunque la poca información publicada indica que las semillas del roble andino carecen de latencia (Gómez et al, 2013); una mejor caracterización del proceso de emergencia y sincronía facilitaría la producción de plántulas para los programas de conservación de la especie.…”