The age of black pine (Pinus nigra Arn. ssp. salzmannii (Dunal) Franco) mother trees has no effect on seed germination and on offspring seedling performance

Abstract

The age of black pine (Pinus nigra Arn. ssp. salzmannii (Dunal) Franco) mother trees has no effect on seed germination and on offspring seedling performance Abstract & Key message We sampled Pinus nigra cones in 29 trees in an age range of 90 to 725 years. The mother tree age did not significantly influence the pinecone or pine seed size, seed germination capacity, or plant size or vigor displayed during the first year of growth in the nursery. & Context Pinus nigra Arn. ssp. salzmannii is a long-lived Mediterranean species, with millenary trees residing in an old-growth forest in the Cazorla Mountain Range in SE Spain which is home to the oldest known trees in the Iberian Peninsula. & Aims This study aimed to assess how the mother tree age in Pinus nigra influences seed viability, germination capacity, and the seedling survival and growth during the first year under nursery conditions. & Methods Twenty-nine trees aged 90 to 725 years were selected and 60 cones were harvested per tree to study the cone characteristics (size and weight), seed viability, and germination capacity in relation to the mother tree age. Eighty germinated seeds per tree were transferred to the nursery and seedling survival and growth were measured after the first growing season. Handling Editor: Andrew MerchantContribution of the co-authors Marta Domínguez Delmás took part in designing the experiment, fieldwork, and tree ring analysis for age determination, and coordinating the research project. Ignacio-García González participated in designing the experiment and fieldwork. Tomasz Wazny took part in designing the experiment, fieldwork, and tree ring analysis for age determination. Javier Vázquez Piqué participated in designing the experiment and fieldwork, running the data analysis, and writing the paper. Manuel Fernández participated in designing the experiment, supervising lab and nursery work with seeds and seedlings, running the data analysis, and writing the paper. Reyes Alejano had the first idea, participated in designing the experiment, and field sampling. He coordinated the works in the lab (cones and seeds assessment and germination tests) and nursery (plantation and follow up of seedlings). He participated in designing the statistical analysis and writing the paper.

On tree longevity

“…the ‘fight trees’ mentioned by Lauder et al ., 2019) would achieve a prolonged lifespan and the associated reproductive output (Dani & Kodandaramaiah, 2019). Species capable of extreme longevity are not only characterized by multiple reproductive cycles over their lifetime but also by the production of viable seeds regardless of age (Lanner & Connor, 2001; Alejano et al ., 2019). Because only past survival, but not past reproductive effort, can be reconstructed over centuries and millennia, it remains impossible to clearly distinguish how fitness evolved with regard to those two adaptation strategies.…”

Genetic diversity within a tree and alternative indexes for different evolutionary effects

“…Empirical studies on the accumulation of somatic mutations of trees and clonal plants yielded varying conclusions: Ally et al (2010) reported a decline in fertility, Bobiwash et al (2013) estimated the accumulation of deleterious mutations in a long-lived clonal shrub. In contrast, Cruzan et al (2022) found within-individual selection in perennial herbs resulting in the production of advantageous mutations in some shoots, while Alejano et al (2019) observed no correlation between fitness of offspring and the age of the parent tree. More empirical studies are needed.…”

Efecto del envejecimiento sobre la capacidad reproductiva de Quercus suber en bosques maduros de espacios protegidos

“…Como consecuencia de esta gestión, es difícil encontrar bosques en los que se haya llegado a las últimas fases de envejecimiento y, en cualquier caso, apenas conocemos el grado de madurez de esos bosques (Peterken, 1996). Sin embargo, ante los nuevos paradigmas de multifuncionalidad en la gestión y gestión próxima a la naturaleza, y bajo los nuevos escenarios de cambio global, resulta de gran interés el estudio de las masas envejecidas poco gestionadas (Alejano et al, 2019). En este sentido, los espacios protegidos, y en concreto, los Parques Nacionales, proporcionan un escenario de estudio privilegiado, ya que tienen como objetivo la conservación de los ecosistemas forestales que albergan.…”

“…En este sentido, tanto la producción de semilla, como su germinación juegan un papel fundamental en la consecución de la regeneración (Lucas-Borja et al, 2017). Sin embargo, hay poca información sobre la capacidad de los bosques maduros para mantener su capacidad reproductiva y producir suficiente semilla viable a medida que se aproximan a la senescencia (Alejano et al, 2019).…”

“…Por tanto, la disponibilidad de semilla y su viabilidad son procesos clave para la persistencia de los bosques maduros. A este respecto, existen evidencias de que la senescencia en los árboles no disminuye la fecundidad en edades avanzadas en términos de producción de semilla (Petit y Hampe, 2006;Mukassabi et al, 2012;Alejano et al, 2019). Sin embargo no se ha estudiado de forma sistemática si la senescencia tiene efectos sobre la viabilidad de la progenie.…”