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1.  Kinship rivalry does not trigger specific allocation strategies in Lupinus angustifolius 
Annals of Botany  2012;110(1):165-175.
Background and Aims
Research on the ability of plants to recognize kin and modify plant development to ameliorate competition with coexisting relatives is an area of very active current exploration. Empirical evidence, however, is insufficient to provide a sound picture of this phenomenon.
An experiment was designed to assess multi-trait phenotypic expression in response to competition with conspecifics of varied degrees of genealogical relatedness. Groups of siblings, cousins and strangers of Lupinus angustifolius were set in competition in a pots assay. Several whole-plant and organ-level traits, directly related to competition for above- and below-ground resources, were measured. In addition, group-level root proliferation was measured as a key response trait to relatedness to neighbours, as identified in previous work.
Key Results
No major significant phenotypic differences were found between individuals and groups that could be assigned to the gradient of relatedness used here. This occurred in univariate models, and also when multi-trait interactions were evaluated through multi-group comparisons of Structural Equation Models. Root proliferation was higher in phenotypically more heterogeneous groups, but phenotypic heterogeneity was independent of the relatedness treatments of the experiment, and root proliferation was alike in the neighbourhoods of siblings, cousins and strangers.
In contrast to recent findings in other species, genealogical relatedness to competing neighbours has a negligible impact on the phenotypic expression of individuals and groups of L. angustifolius. This suggests that kin recognition needs further exploration to assess its generality, the ecological scenarios where it might have been favoured or penalized by natural selection, and its preponderance in different plant lineages.
PMCID: PMC3380590  PMID: 22562807
Kin selection; Lupinus angustifolius; structural equation models; phenotypic plasticity; kin recognition; intraspecific competition
2.  Inherited variability in multiple traits determines fitness in populations of an annual legume from contrasting latitudinal origins 
Annals of Botany  2009;103(8):1279-1289.
Background and Aims
Variation in fitness depends on corresponding variation in multiple traits which have both genetically controlled and plastic components. These traits are subjected to varying degrees of local adaptation in specific populations and, consequently, are genetically controlled to different extents. In this study it is hypothesized that modulation of different traits would have contrasting relevance for the fitness of populations of diverse origins. Specifically, assuming that environmental pressures vary across a latitudinal gradient, it is suggested that inherited variation in traits differentially determines fitness in annual Lupinus angustifolius populations from contrasting latitudinal origins in western Spain.
Seeds of L. angustifolius from three contrasting origins were grown in a common garden. Traits related to more plastic vegetative growth and more genetically conserved phenology were measured, together with estimates of reproductive success. Fitness was estimated by the number of viable seeds per plant. Structural Equation Models were used to infer causal relationships among multiple traits and fitness, separating the direct and indirect effects of morphological, phenological and reproductive traits.
Key Results
Phenological, vegetative and reproductive traits accounted for most of the fitness variation. Fitness was highest in plants of southernmost origin, mainly due to earlier flowering. Fitness within each seed origin was controlled by variation in different traits. Southern origin plants that grew to a larger size achieved higher fitness. However, plant size in plants of northernmost origin was irrelevant, but early flowering promoted higher fitness. Variation in fruit and seed set had a greater effect on the fitness of plants of central origin than phenological and size variation.
It is concluded that modulation of a functional trait can be relevant to fitness in a given population (i.e. affecting intensity and direction), but irrelevant in other populations. This points to the need to consider integrated phenotypes when trying to unravel local adaptation effects over single traits.
PMCID: PMC2685322  PMID: 19318383
Lupinus; Structural Equation Models; fitness; phenology; functional traits; reproductive success; SLA; seed size
3.  Local Adaptation Enhances Seedling Recruitment Along an Altitudinal Gradient in a High Mountain Mediterranean Plant 
Annals of Botany  2007;99(4):723-734.
Background and Aims
Germination and seedling establishment, which are critical stages in the regeneration process of plant populations, may be subjected to natural selection and adaptive evolution. The aims of this work were to assess the main limitations on offspring performance of Silene ciliata, a high mountain Mediterranean plant, and to test whether local adaptation at small spatial scales has a significant effect on the success of establishment.
Reciprocal sowing experiments were carried out among three populations of the species to test for evidence of local adaptation on seedling emergence, survival and size. Studied populations were located at the southernmost margin of the species' range, along the local elevation gradient that leads to a drought stress gradient.
Key Results
Drought stress in summer was the main cause of seedling mortality even though germination mainly occurred immediately after snowmelt to make the best use of soil moisture. The results support the hypothesis that species perform better at the centre of their altitudinal range than at the boundaries. Evidence was also found of local adaptation in seedling survival and growth along the whole gradient.
The local adaptation acting on seedling emergence and survival favours the persistence of remnant populations on the altitudinal and latitudinal margins of mountain species. In a global warming context, such processes may help to counteract the contraction of this species' ranges and the consequent loss of habitat area.
PMCID: PMC2802927  PMID: 17307775
Silene ciliata; local adaptation; southern border; reciprocal sowing; drought stress; altitude gradient
4.  Environmental Scales on the Reproduction of a Gypsophyte: A Hierarchical Approach 
Annals of Botany  2007;99(3):519-527.
Background and Aims
Environmental variability at several scales can determine plant reproductive success. The main goal of this work was to model the reproductive flexibility of a semi-arid specialist considering different scales of environmental variability.
A 2-year field study was performed on the determinants of the female reproductive success of Helianthemum squamatum, an Iberian gypsophyte, considering two scales of environmental variability: differences between two contrasting slope aspects; and, on individual scale, the neighbouring microenvironment. Generalized linear mixed models were used to evaluate simultaneously the potential effects of environmental variability at both scales, together with flowering phenology and plant size on the reproductive output of H. squamatum. The following reproductive response variables were considered: number of flowers, fruit-set, number of viable and aborted seeds per fruit, and number of seeds per plant.
Key Results
Contrary to expectations, environmental variability exerted a weak or even absent effect on the reproductive variables considered, while flowering phenology and plant size, which did not vary between slopes, played a major role. Surprisingly, the absolute reproductive variables were even higher in the extremely dry year of 2003, although only on the south-facing slope. The relatively milder conditions of the north-facing slope did not involve any advantage to this species in terms of reproductive output.
The species seemed to be considerably well adapted to the environmental unpredictability characteristic of Mediterranean systems, considering its ability to maintain reproduction across contrasting environments and contrasting climatic conditions. These findings make us face the question of what must be considered stressful conditions in the case of a stress-tolerant specialist.
PMCID: PMC2802956  PMID: 17237214
Helianthemum squamatum; environmental variability; semi-arid; reproductive output; flowering phenology; gypsophyte
5.  Plants Living on Gypsum: Beyond the Specialist Model 
Annals of Botany  2007;99(2):333-343.
Background and Aims
Plants from gypsum habitats are classified as gypsophiles and gypsovags. The former include both narrow endemics limited to small gypsum areas and regionally dominant gypsophiles growing in gypsum areas of large regions, whereas gypsovags are plants that can grow both in gypsum and non-gypsum soils. Factors controlling the distribution of gypsum plants are still not fully understood.
To assess how the different types of gypsum plants deal with the stressful conditions of gypsum substrates, comparisons were made of the leaf chemical composition of four gypsovags, five regionally dominant gypsophiles and four narrow gypsum endemics growing in two massive gypsum areas of the Iberian Peninsula.
Key Results
The chemical composition of gypsovags was clearly different from regionally dominant gypsophiles, while the chemical composition of narrow-gypsophile endemics was more similar to the chemical composition of gypsovags than to that of regionally dominant gypsophiles. Regionally dominant gypsophiles showed higher concentrations of ash, Ca, S, N, Mg P and Na, whereas gypsovags and local gypsophile endemics displayed higher concentrations of C and greater C : N ratios.
Such differences suggest that the three groups of gypsum plants follow diverse ecological strategies. It is suggested that regionally dominant gypsophiles might fit the ‘specialist’ model, being species specifically adapted to gypsum, whereas both gypsovags and narrow-gypsophile endemics might fit the ‘refuge’ model, being stress-tolerant species that find refuge on gypsum soils from competition. The analysis of the leaf chemical composition could be a good predictor of the degree of plants specialization to gypsum soils.
PMCID: PMC2802996  PMID: 17204537
Gypsophily; gypsum-rich soils; leaf chemical composition; narrow-endemic gypsophytes; Mediterranean semi-arid environments; plant conservation; edaphic endemism

Results 1-5 (5)