Longitudinal analysis of Plantago: Age-by-environment interactions reveal aging

Department of Biology, University of Virginia, Charlottesville, Virginia 22904-4328, USA.
Ecology (Impact Factor: 5). 07/2009; 90(6):1427-33. DOI: 10.1890/08-0981.1
Source: PubMed

ABSTRACT We know very little about aging (senescence) in natural populations, and even less about plant aging. Demographic aging is identified by an increasing rate of mortality following reproductive maturity. In natural populations, quantifying aging is often confounded because changes in mortality may be influenced by both short- and long-term environmental fluctuations as well as age-dependent changes in performance. Plants can be easily marked and monitored longitudinally in natural populations yet the age-dependent dynamics of mortality are not known. This study was designed to determine whether a plant species, Plantago lanceolata, shows demographic aging in its natural environment. A large, multiple-cohort design was used to separate age-independent and age-dependent processes. Seven years of results show environmental influences on mortality as evidenced by synchronous changes in mortality across four cohorts over time. Age-dependent mortality was found through an age-by-environment interaction when the oldest cohorts had significantly higher mortality relative to the younger cohorts during times of stress. Neither size nor quantity of reproduction could explain this variation in mortality across cohorts. These results demonstrate demographic senescence in a natural population of plants.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Senescence, the deterioration of morphological, physiological, and reproductive functions with age that ends with the death of the organism, was widely studied in plants. Genes were identified that are linked to the deterioration of cells, organs and the whole plant. It is, however, unclear whether those genes are the source of age dependent deterioration or get activated to regulate such deterioration. Furthermore, it is also unclear whether such genes are active as a direct consequence of age or because they are specifically involved in some developmental stages. At the individual level, it is the relationship between quantitative genetic variation, and age that can be used to detect the genetic signature of senescence. Surprisingly, the latter approach was only scarcely applied to plants. This may be the consequence of the demanding requirements for such approaches and/or the fact that most research interest was directed toward plants that avoid senescence. Here, I review those aspects in turn and call for an integrative genetic theory of senescence in plants. Such conceptual development would have implications for the management of plant genetic resources and generate progress on fundamental questions raised by aging research.
    Frontiers in Genetics 02/2015; 6:57. DOI:10.3389/fgene.2015.00057
  • [Show abstract] [Hide abstract]
    ABSTRACT: Pathogens are considered to drive ecological and evolutionary dynamics of plant populations, but we lack data measuring the population-level consequences of infection in wild plant–pathogen interactions. Moreover, while it is often assumed that offseason environmental conditions drive seasonal declines in pathogen population size, little is known about how offseason environmental conditions impact the survival of pathogen resting stages, and how critical the offseason is for the next season's epidemic.The fungal pathogen Podosphaera plantaginis persists as a dynamic metapopulation in the large network of Plantago lanceolata host populations. Here, we analyze long-term data to measure the spatial synchrony of epidemics and consequences of infection for over 4000 host populations. Using a theoretical model, we study whether large-scale environmental change could synchronize disease occurrence across the metapopulation.During 2001–2013 exposure to freezing decreased, while pathogen extinction–colonization–persistence rates became more synchronized. Simulations of a theoretical model suggest that increasingly favorable winter conditions for pathogen survival could drive such synchronization. Our data also show that infection decreases host population growth.These results confirm that mild winter conditions increase pathogen overwintering success and thus increase disease prevalence across the metapopulation. Further, we conclude that the pathogen can drive host population growth in the Plantago–Podosphaera system.
    New Phytologist 11/2014; 205(3). DOI:10.1111/nph.13145 · 6.55 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We explore how plant morphology constrains renewal and replacement of modules in the plant body and further, we investigate the idea that most of the important morphological characteristics in relation to senescence are evolutionarily conservative, and therefore shaped by developmental constraints that are not easily overcome by selective forces. Although plants are very flexible in production of new plant modules, continuous replacement of old modules is not a rule due to energy exhaustion in monocarpic plants and inability of some perennials to replace essential plant organs like trunk and/or main root in non-clonal plants. Plant senescence was examined recently in several top journals (New Phytologist, Journal of Ecology, Nature) and the morphollgical constraints of modular plant growth were not taken into account. We believe considering morphological constraints of plant growth will help to ask proper questions in research of whole plant senescence.
    New Phytologist 02/2015; 206:14-18. DOI:10.1111/nph.13160 · 6.55 Impact Factor

Full-text (2 Sources)

Available from
Nov 3, 2014