scholarly journals Straightening the crooked: intraspecific divergence of stem posture control and associated trade-offs in a model conifer

2021 ◽  
Author(s):  
R Sierra-de-Grado ◽  
V Pando ◽  
J Voltas ◽  
R Zas ◽  
J Majada ◽  
...  
Keyword(s):  
Mechanical Stability ◽  
Common Garden ◽  
Shoot Elongation ◽  
Reaction Wood ◽  
Forest Trees ◽  
Manipulative Experiment ◽  
Intraspecific Divergence ◽  
Trade Offs ◽  
Adaptive Phenotypic Plasticity ◽  
Light Capture

Abstract Although the straightening capacity of the stem is key for light capture and mechanical stability in forest trees, little is known about its adaptive implications. Assuming that stem straightening is costly, trade-offs are expected with competing processes such as growth, maintenance and defences. We established a manipulative experiment in a common garden of Pinus pinaster including provenances typically showing either straight-stemmed or crooked-stemmed phenotypes. We imposed a bending up to 35º on plants aged nine years of both provenance groups and followed the straightening kinetics and shoot elongation after releasing. Eight months later, we destructively assessed biomass partitioning, reaction wood, wood microdensity, xylem reserve carbohydrates and phloem secondary metabolites. The experimental bending and release caused significant, complex changes with a marked difference between straight- and crooked-type plants. The straight-type recovered verticality faster and to a higher degree and developed more compression wood, while displaying a transitory delay in shoot elongation, reducing resource allocation to defences and maintaining the levels of non-structural carbohydrates compared to the crooked type. This combination of responses indicates the existence of intraspecific divergence in the reaction to mechanical stresses which may be related to different adaptive phenotypic plasticity.

Sex ratio and life history traits at reaching sexual maturity in the dioecious shrub Fuchsia parviflora: field and common garden experiments

2021 ◽  
pp. 1-6
Author(s):  
Jessica S. Ambriz ◽  
Clementina González ◽  
Eduardo Cuevas
Keyword(s):  
Natural Population ◽  
Sexual Maturity ◽  
Sex Ratios ◽  
Natural Populations ◽  
Common Garden ◽  
Common Garden Experiment ◽  
Trade Offs ◽  
Reproductive Biomass ◽  
Common Garden Experiments ◽  
Growth And Reproduction

Abstract Fuchsia parviflora is a dioecious shrub that depends on biotic pollination for reproduction. Previous studies suggest that the male plants produce more flowers, and male-biased sex ratios have been found in some natural populations. To assess whether the biased sex ratios found between genders in natural populations are present at the point at which plants reach sexual maturity, and to identify possible trade-offs between growth and reproduction, we performed a common garden experiment. Finally, to complement the information of the common garden experiment, we estimated the reproductive biomass allocation between genders in one natural population. Sex ratios at reaching sexual maturity in F. parviflora did not differ from 0.5, except in one population, which was the smallest seedling population. We found no differences between genders in terms of the probability of germination or flowering. When flowering began, female plants were taller than males and the tallest plants of both genders required more time to reach sexual maturity. Males produced significantly more flowers than females, and the number of flowers increased with plant height in both genders. Finally, in the natural population studied, the investment in reproductive biomass was seven-fold greater in female plants than in male plants. Our results showed no evidence of possible trade-offs between growth and reproduction. Despite the fact that female plants invest more in reproductive biomass, they were taller than the males after flowering, possibly at the expense of herbivory defence.

scholarly journals Attraction, Dynamics, and Phase Transitions in Fire Ant Tower-Building

2019 ◽  
Author(s):  
Gary K. Nave ◽  
Nelson T. Mitchell ◽  
Jordan A. Chan Dick ◽  
Tyler Schuessler ◽  
Joaquin A. Lagarrigue ◽  
...  
Keyword(s):  
Mechanical Stability ◽  
Center Of Mass ◽  
Functional Materials ◽  
Random Motion ◽  
Trade Offs ◽  
Behavioral Rules ◽  
Building Process ◽  
Biological Studies ◽  
Collective Construction ◽  
In Fire

AbstractMany insect species, and even some vertebrates, assemble their bodies to form multi-functional materials that combine sensing, computation, and actuation. The tower-building behavior of red imported fire ants, Solenopsis invicta, presents a key example of this phenomenon of collective construction. While biological studies of collective construction focus on behavioral assays to measure the dynamics of formation and studies of swarm robotics focus on developing hardware that can assemble and interact, algorithms for designing such collective aggregations have been mostly overlooked. We address this gap by formulating an agent-based model for collective tower-building with a set of behavioral rules that incorporate local sensing of neighboring agents. We find that an attractive force makes tower building possible. Next, we explore the trade-offs between attraction and random motion to characterize the dynamics and phase transition of the tower building process. Lastly, we provide an optimization tool that may be used to design towers of specific shapes, mechanical loads, and dynamical properties such as mechanical stability and mobility of the center of mass.

Provisional breeding zone determination modeled as a maximal covering location problem

2005 ◽  
Vol 35 (5) ◽  
pp. 1173-1182 ◽  
Author(s):  
Kevin A Crowe ◽  
William H Parker
Keyword(s):  
Pinus Banksiana ◽  
Location Problem ◽  
Focal Point ◽  
Genetic Material ◽  
Common Garden ◽  
Zone Method ◽  
Maximal Covering ◽  
Trade Offs ◽  
Seed Zone ◽  
Point Seed

This study was a first attempt to model the problem of delineating breeding zones as a maximal covering location problem. The method involves two steps. First, a comprehensive set of candidate breeding zones is generated for a region using the focal point seed zone method. This method allows for control over the adaptive difference of genetic material within each zone. A grid of points is used to create the set of candidate breeding zones: one zone per point. Next, candidate zones are entered into a maximal covering location model formulated to suit this problem. The objective of this model is to select a subset of candidate zones that maximally covers the area of the region, given a limit on the number of zones to be selected and on the adaptive dissimilarity allowed within zones. Through use of this method, decision-makers can gain insight into how many breeding zones are needed to cover the region. Using different inputs from the focal point seed zone method, it is also possible to explore the trade-offs between the quantity and the quality of breeding zones. The method was tested on data from a series of jack pine (Pinus banksiana Lamb.) common garden trials of 102 seed sources from northwestern Ontario.

scholarly journals Trade-offs and selection conflicts in hybrid poplars indicate the stomatal ratio as an important trait regulating disease resistance

2019 ◽  
Author(s):  
Karl C. Fetter ◽  
David M. Nelson ◽  
Stephen R. Keller
Keyword(s):  
Disease Resistance ◽  
Common Garden ◽  
Phenotypic Variance ◽  
Populus Balsamifera ◽  
Rust Disease ◽  
Stomata Density ◽  
Hybrid Poplars ◽  
Intermediate Phenotypes ◽  
Trade Offs ◽  
A Genome

ABSTRACTNatural selection can remove maladaptive genotypic variance from populations, leaving reduced phenotypic variation as a signal of its action. Hybrid populations offer a unique opportunity to study phenotypic variance before selection purifies it, as these populations can have increased genotypic and phenotypic variance than can reveal trade-offs and selection conflicts not visible, or visible to a lesser extent, in unadmixed populations. Here, we study the interactions between a fungal leaf rust disease (Melampsora medusae) and stomata and ecophysiology traits in a set of hybrid and unadmixed individuals formed by natural matings between Populus balsamifera, P. trichocarpa, P. angustifolia, and P. deltoides. Phenotypes were measured on cloned genotypes grown in a common garden and genotyped at 227K SNPs with GBS. Our analyses indicate hybridization decreases disease resistance and increases the variance of stomatal ratio (SR), or the ratio of upper leaf surface stomata density to total stomata density. Heritability of SR was high in admixed populations (H2 = 0.72) and covaries strongly with the proportion of P. balsamifera ancestry in a genome; thus, selection could effectively reduce disease by selecting for low values of stomatal ratio. However, selection conflicts present in some admixed populations may prevent adaptation to pathogens as a result of these populations being unable to occupy adaptive trait space along the growth-defense spectrum. These results suggest an important role for SR and stomatal patterning traits as a target of pathogen induced selection to achieve local fitness optima. Additionally, we demonstrate that hybridization is capable of generating, or magnifying maladaptive intermediate phenotypes to reveal trade-offs and selection conflicts.

Mechanical properties and structure–function trade-offs in secondary xylem of young roots and stems

2019 ◽  
Vol 70 (14) ◽  
pp. 3679-3691 ◽  
Author(s):  
Lenka Plavcová ◽  
Friederike Gallenmüller ◽  
Hugh Morris ◽  
Mohammad Khatamirad ◽  
Steven Jansen ◽  
...  
Keyword(s):  
Wood Density ◽  
Cell Walls ◽  
Mechanical Stability ◽  
Secondary Xylem ◽  
Mechanical Stiffness ◽  
Xylem Structure ◽  
Major Constraint ◽  
Trade Offs ◽  
Clematis Vitalba ◽  
Torsional Properties

AbstractBending and torsional properties of young roots and stems were measured in nine woody angiosperms. The variation in mechanical parameters was correlated to wood anatomical traits and analysed with respect to the other two competing functions of xylem (namely storage and hydraulics). Compared with stems, roots exhibited five times greater flexibility in bending and two times greater flexibility in torsion. Lower values of structural bending and structural torsional moduli (Estr and Gstr, respectively) of roots compared with stems were associated with the presence of thicker bark and a greater size of xylem cells. Across species, Estr and Gstr were correlated with wood density, which was mainly driven by the wall thickness to lumen area ratio of fibres. Higher fractions of parenchyma did not translate directly into a lower wood density and reduced mechanical stiffness in spite of parenchyma cells having thinner, and in some cases less lignified, cell walls than fibres. The presence of wide, partially non-lignified rays contributed to low values of Estr and Gstr in Clematis vitalba. Overall, our results demonstrate that higher demands for mechanical stability in self-supporting stems put a major constraint on xylem structure, whereas root xylem can be designed with a greater emphasis on both storage and hydraulic functions.

A model of genetic variation for Pinus ponderosa in the Inland Northwest (U.S.A.): applications in gene resource management

1991 ◽  
Vol 21 (10) ◽  
pp. 1491-1500 ◽  
Author(s):  
G. E. Rehfeldt
Keyword(s):  
Genetic Variation ◽  
Pinus Ponderosa ◽  
Regression Models ◽  
Common Garden ◽  
Shoot Elongation ◽  
The United States ◽  
Independent Data ◽  
Gene Conservation ◽  
Seed Transfer ◽  
Inland Northwest

Models were developed to describe genetic variation among 201 seedling populations ofPinusponderosa var. ponderosa in the Inland Northwest of the United States. Common-garden studies provided three variables that reflected growth and development in field environments and three principal components of six variables that reflected patterns of shoot elongation. Regression models were developed for describing genetic variation across the landscape. Using functions of latitude, longitude, and elevation as descriptors, these models produced values of R2 that were as large as 0.66, while averaging 0.39. The models described genetic variation as occurring along relatively steep elevational clines and gentle geographic (i.e., latitudinal and longitudinal) clines. An exercise at validating the models with independent data supported their veracity. Predictions made by the models are applied to limiting seed transfer, designing breeding zones, planning gene conservation programs, interpreting phenotypic variation, and predicting the effects of environmental change on the adaptedness of populations.

Life history evolution in heterogeneous environments: a review of theory

1996 ◽  
Vol 351 (1345) ◽  
pp. 1349-1359 ◽  
Keyword(s):  
Life History ◽  
Life History Evolution ◽  
Common Garden ◽  
Experimental Tests ◽  
Heterogeneous Environments ◽  
Simulation Studies ◽  
Trade Offs ◽  
Fitness Measures ◽  
History Evolution ◽  
Common Garden Experiments

Analysis of life history evolution in spatially heterogeneous environments was revolutionized by the demonstration by Kawecki & Stearns (1993) and Houston & McNamara (1992) that earlier treatments had used incorrect fitness measures. The implications of this for the analysis of organisms with and without phenotypic plasticity are reviewed. It is shown that analyses ignoring age structure can give misleading results. The plausibility and implications of the assumptions are discussed, and suggestions are made for further work. The usefulness of reciprocal transplant and common garden experiments, in providing information relevant to the assumptions and predictions, is emphasized. Two simulation studies show that life history evolution in temporally heterogeneous environments in which trade-offs are fixed are well predicted by Schaffer’s (1974) model, with modification for asymmetric variations as necessary. Unfortunately the period of study needed to observe such effects is so long as to preclude experimental tests for most organsims.

scholarly journals Syndromes in suites of correlated traits suggest multiple mechanisms facilitating invasion in a plant range-expander

NeoBiota ◽  
2018 ◽  
Vol 37 ◽  
pp. 1-22 ◽  
Author(s):  
Lisa Johanna Tewes ◽  
Caroline Mueller
Keyword(s):  
Common Garden ◽  
Plant Invasions ◽  
Individual Species ◽  
Multiple Traits ◽  
Correlated Traits ◽  
Invasion Mechanisms ◽  
Trade Offs ◽  
Population Origin ◽  
Species Specific ◽  
Native Invasive

Various mechanisms can facilitate the success of plant invasions simultaneously, but may be difficult to disentangle. In the present study, plants of the range-expanding species Bunias orientalis from native, invasive and naturalised, not yet invasive populations were compared in a field common garden over two years. Plants were grown under two nitrate-regimes and multiple traits regarding growth, defence, antagonist loads and reproduction were measured. A rank-based clustering approach was used to assign correlated traits to distinct suites. These suites were analysed for “syndromes” that are expressed as a function of population origin and/or fertilisation treatment and might represent different invasion mechanisms. Indeed, distinct suites of traits were differentially affected by these factors. The results suggest that several pre-adaptation properties, such as certain growth characteristics and intraspecific chemical variation, as well as post-introduction adaptations to antagonists and resource availability in novel habitats, are candidate mechanisms that facilitate the success of invasive B. orientalis in parallel. It was concluded that rank-based clustering is a robust and expedient approach to integrate multiple traits for elucidating invasion syndromes within individual species. Studying a multitude of traits at different life-history and establishment stages of plants grown under distinct resource treatments reveals species-specific trade-offs and resource sinks and simplifies the interpretation of trait functions for the potential invasive success of plants.

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