Do perennials really senesce?

Munné‐Bosch, Sergi

doi:10.1016/j.tplants.2008.02.002

Cited by 129 publications

(110 citation statements)

References 46 publications

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“…Additionally, declining growth is sometimes considered to be a defining feature of plant senescence 12 . Our findings are thus relevant to understanding the nature and prevalence of senescence in the life history of perennial plants 27 . Finally, our results are relevant to understanding and predicting forest feedbacks to the terrestrial carbon cycle and global climate system [1][2][3] .…”

Section: Research Lettermentioning

confidence: 85%

Rate of tree carbon accumulation increases continuously with tree size

Stephenson

Das

Condit

et al. 2014

Nature

743

486

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After more than a century of research the typical growth pattern of a tree was thought to be fairly well understood. Following germination height growth accelerates for some time, then increment peaks and the added height each year becomes less and less. The cross sectional area (basal area) of the tree follows a similar pattern, but the maximum basal area increment occurs at some time after the maximum height increment. An increase in basal area in a tall tree will add more volume to the stem than the same increase in a short tree, so the increment in stem volume (or mass) peaks very late. Stephenson et al. challenge this paradigm, and suggest that mass increment increases continuously. Their analysis methods however are a textbook example of the 'ecological fallacy', and their conclusions therefore unsupported.

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Section: Research Lettermentioning

confidence: 85%

Rate of tree carbon accumulation increases continuously with tree size

Stephenson

Das

Condit

et al. 2014

Nature

743

486

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“…In other cases, however, reduced apical dominance prior to flowering has been found to favor iteroparity by increasing the number of lateral shoots committed to vegetative rather than reproductive fates (Wang et al 2009; Donohue 2011, 2012; see Figure 1C). Semelparous and iteroparous plants can also differ quantitatively in physiological processes regulating rates of leaf senescence (Thomas et al 2000;Munné-Bosch 2008). However, the extent to which quantitative variation in meristem fate allocation vs. physiological processes explains variation in resource allocation within iteroparous species remains largely unknown.…”

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confidence: 99%

“…Vegetative or dormant meristems can later become reproductive, but commitment to reproductive growth is generally irreversible. Thus, iteroparous plants, which undergo multiple cycles of reproduction, need to have some meristems that remain vegetative beyond the first growing season (Thomas et al 2000;Munné-Bosch 2008). Bonser and Aarssen (2006) found that herbaceous iteroparous species had greater apical dominance (i.e., repression of lateral shoot growth by an active main shoot) than semelparous relatives, which die after a single reproductive episode.…”

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confidence: 99%

Complex Genetic Effects on Early Vegetative Development Shape Resource Allocation Differences BetweenArabidopsis lyrataPopulations

et al. 2013

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Costs of reproduction due to resource allocation trade-offs have long been recognized as key forces in life history evolution, but little is known about their functional or genetic basis. Arabidopsis lyrata, a perennial relative of the annual model plant A. thaliana with a wide climatic distribution, has populations that are strongly diverged in resource allocation. In this study, we evaluated the genetic and functional basis for variation in resource allocation in a reciprocal transplant experiment, using four A. lyrata populations and F 2 progeny from a cross between North Carolina (NC) and Norway parents, which had the most divergent resource allocation patterns. Local alleles at quantitative trait loci (QTL) at a North Carolina field site increased reproductive output while reducing vegetative growth. These QTL had little overlap with flowering date QTL. Structural equation models incorporating QTL genotypes and traits indicated that resource allocation differences result primarily from QTL effects on early vegetative growth patterns, with cascading effects on later vegetative and reproductive development. At a Norway field site, North Carolina alleles at some of the same QTL regions reduced survival and reproductive output components, but these effects were not associated with resource allocation trade-offs in the Norway environment. Our results indicate that resource allocation in perennial plants may involve important adaptive mechanisms largely independent of flowering time. Moreover, the contributions of resource allocation QTL to local adaptation appear to result from their effects on developmental timing and its interaction with environmental constraints, and not from simple models of reproductive costs. DIFFERENTIAL allocation of resources to current reproduction vs. continued growth and maintenance is a central feature of life history differences among organisms (Stearns 1992;Roff and Fairbairn 2007). Reproduction is widely recognized as costly, leading to trade-offs between investment in reproduction vs. growth and maintenance and ultimately survival (Bell 1980;Reznick 1985;Lovett Doust 1989). Optimal resource allocation strategies are likely to vary by environment due to differential effects of allocation on growth rates, survival, and fecundity, thus leading to selection for different allocation strategies in different environments (Williams 1966;Charnov and Schaffer 1973;Bell 1980;Reznick 1985;Biere 1995;Johnson 2007).Among iteroparous organisms, which must allocate some resources to somatic maintenance in order to survive to reproduce multiple times, a wide range of proportional investments in growth and maintenance vs. reproduction is possible (van Noordwijk and De Jong 1986). Genetic variation in traits subject to trade-offs results in what has been termed "structured pleiotropy," in which genetic covariances between traits result from functional constraints imposed by the limiting resources (De Jong 1990;Stearns et al. 1991; see Figure 1B). However, differences in resource acquisi...

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“…A vast number of organisms such as trees (Watkinson 1992, Munné-Bosch 2008, fish (Reznick et al 2004), and many reptiles (Congdon et al 2003, Sparkman et al 2007, Tumarkin-Deratzian et al 2007, have the capacity to growth indefinitely, a mechanism that is known as indeterminate growth (Kozłowski andUchmanski 1987, Karkach 2006). Scholars have argued that in these species, size plays the dominant role in shaping life-history traits such as maturation and survival, while chronological age is of marginal importance in their demography (Kirkpatrick 1984, Menges 2000, Caswell 2001).…”

Section: Introductionmentioning

confidence: 99%

“…Indeterminate growth is extremely common in clonal species without soma and germline segregation such as plants (Watkinson 1992, Munné-Bosch 2008 and in many invertebrates (Nilsson Skö ld and Obst 2011). It is also found in species with sexual reproduction that show continuous somatic growth after maturity, like mussels (Philipp and Abele 2010), fish (Reznick et al 2004), turtles (Congdon et al 2003), snakes (Sparkman et al 2007), and crocodiles (Tumarkin-Deratzian et al 2007).…”

Section: Introductionmentioning

confidence: 99%

Mortality as a bivariate function of age and size in indeterminate growers

Colchero

Schaible

2014

Ecosphere

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Citation: Colchero, F., and R. Schaible. 2014. Mortality as a bivariate function of age and size in indeterminate growers.Ecosphere 5(12):161. http://dx.doi.org/10.1890/ES14-00306.1Abstract. Mortality in organisms that grow indefinitely, known as indeterminate growers, is thought to be driven primarily by size. However, a number of ageing mechanisms also act as functions of age. Thus, to explain mortality in these species, both size and age need to be explicitly modeled. Here we developed a model that treats age-and size-specific mortality as a bivariate process. This method facilitates the exploration of the underlying (unobserved) contributions of age and size to mortality. We show that, in theory, a population can show declining mortality with age and size while the underlying contribution of age, as a proxy for chronological deterioration, is of typical senescence; while a seemingly senescent population can have underlying age-related negative senescence, which is, however, overcome by negative underlying size effects (i.e., increasing size-specific mortality). We show how inference about these unobserved processes can be made using a simple Bayesian model, and how all of the mortality parameters are accurately retrieved. We then apply the methods to published datasets on water pythons and freshwater mussels and test different hypotheses regarding the effects of age and size on mortality. In both cases we found age-dependent senescent mortality, with size having only negligible effects. The methods we present here can help to improve the demographic models commonly applied to a vast number of species of commercial and conservation importance such as fish, trees or bivalves, among many other, for which both age and size are relevant. In addition, the application of these methods can help to shed light on the existence of processes such as negative senescence, and contribute to our understanding of the evolutionary mechanisms of senescence in species that do not fit the established theories.

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Do perennials really senesce?

Cited by 129 publications

References 46 publications

Rate of tree carbon accumulation increases continuously with tree size

Rate of tree carbon accumulation increases continuously with tree size

Complex Genetic Effects on Early Vegetative Development Shape Resource Allocation Differences BetweenArabidopsis lyrataPopulations

Mortality as a bivariate function of age and size in indeterminate growers

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