Leaf longevity and structure, fruit mass and phenology in 52 cultivated varieties and wild accessions of olive

Abstract Although phenology has long been recognized as a critical feature for the adaptation of organisms to their local environment, until recently, phenological events have seldom been considered in the broader context of trait‐based ecology. Here, we assess the association between phenology and two key traits structuring the phenotype: (i) leaf longevity, or leaf life span, which is a pivotal trait for plant resource use through its role in the so‐called ‘leaf economics spectrum’, and (ii) fruit mass, which contributes to a syndrome evolved by plants to promote seed dispersal. Leaf—production and loss—and reproductive—flowering and fruiting phases—phenology was followed during 4 years on 52 cultivated varieties and wild accessions of olive ( Olea europaea L. subsp. europaea ) maintained in an ex situ varietal collection located in the Mediterranean Region of southern France. Leaf life span was derived from leaf phenology censuses. Leaf mass per area and leaf nitrogen content were measured to test whether leaf life span and phenology were associated with these two other central traits of the leaf economics spectrum. Fruit fresh mass at harvest was determined to assess the association between reproductive phenology and reproductive output. There was a twofold variation in average leaf life span across varieties, which was related to both the time of peak loss of leaves and the duration of the leaf loss period. We found no evidence that leaf life span and leaf phenology were related to the two other traits of the leaf economics spectrum. Fruit fresh mass, which varied 10‐fold across varieties, was twice as large in cultivated olives than in wild olives. It was related to several phases of reproductive phenology, including fruit development time. Leaf and reproductive phenologies were found to be largely uncoupled. Leaf phenology emerges as a functional dimension largely independent of plant resource use, while reproductive phenology appears as a minor determinant of fruit mass. Overall, these results demonstrate weak associations between phenology and traits describing other aspects of plant form and function within the olive species. Read the free Plain Language Summary for this article on the Journal blog.