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Universidade de Coimbra (2018)

Size matters : The role of plant genome size on post-fire regeneration strategies

Lopes, Sara Maria Brito

Lopes, Sara Maria Brito

Titre : Size matters : The role of plant genome size on post-fire regeneration strategies

Auteur : Lopes, Sara Maria Brito

Université de soutenance : Universidade de Coimbra

Grade : Mestrado em Ecologia 2018

Résumé
The selective pressure that fire has exerted on plant communities, along millions of years, as resulted on the development of post-fire regeneration strategies by plants from fire-prone regions. There are two distinct post-fire regeneration strategies : resprouting, which allows persistence at individual level, because the adult plant after being destroyed by fire action has the capacity to initiate new buds through meristematic cells that survive the high temperatures ; and post-fire seedling recruitment which allows persistence at populational level, because the adult plant is killed by fire and the fate of the population depends exclusively on seedling emergence from a seed bank. These strategies are related to a specific set of morphological and physiological traits. Resprouting species invest more resources at root level, where they accumulate resources essential for resprouting and, thus, grow slowly. Species who recruit after fire, invest more resources in fast growth and maturation, higher fecundity and photosynthetic rates, which allow the occupation of the new open spaces created by fire action. These plant traits are influenced by genome size through its direct effect on cell size and cellular division processes, which, in turn, impose trade-offs that limit the possible sets of plant traits. Based on the principle that most of the plant traits associated with post-fire recruitment are favoured by small genome sizes, a negative relationship with genome size would be expected between genome size and post-fire recruitment. T

Mots clés  : Características morfológicas e fisiológicas ; estratégias de regeneração pós-fogo ; rebrote ; recrutamento pós-fogo ; tamanho do genoma ; Genome size ; plant traits ; post-fire recruitment ; post-fire regeneration strategies ; resprouting

Présentation

Page publiée le 20 juin 2020