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. 2013 May 15;280(1762):20130921.
doi: 10.1098/rspb.2013.0921. Print 2013 Jul 7.

Does seed mass drive the differences in relative growth rate between growth forms?

Jennie Houghton  1 , Ken Thompson, Mark Rees
Affiliations

Does seed mass drive the differences in relative growth rate between growth forms?

Jennie Houghton et al. Proc Biol Sci. .

Abstract

The idea that herbaceous plants have higher relative growth rates (RGRs) compared with woody plants is fundamental to many of the most influential theories in plant ecology. This difference in growth rate is thought to reflect systematic variation in physiology, allocation and leaf construction. Previous studies documenting this effect have, however, ignored differences in seed mass. As woody species often have larger seeds and RGR is negatively correlated with seed mass, it is entirely possible the lower RGRs observed in woody species is a consequence of having larger seeds rather than different growth strategies. Using a synthesis of the published literature, we explored the relationship between RGR and growth form, accounting for the effects of seed mass and study-specific effects (e.g. duration of study and pot volume), using a mixed-effects model. The model showed that herbaceous species do indeed have higher RGRs than woody species, and that the difference was independent of seed mass, thus at all seed masses, herbaceous species on average grow faster than woody ones.

Keywords: plant strategies; relative growth rate; seed mass.

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Figures

Figure 1.
Figure 1.
The relationships between the experimental variables. (a) RGR and growth form (p < 0.0001), (b) RGR and duration (p < 0.0001), (c) RGR and pot volume (p < 0.0001), (d) seed mass and duration (p < 0.001), (e) seed mass and volume (p < 0.0002) and (f) volume and duration (p < 0.0001). All variables except growth form are displayed on the log scale. p-values generating a sample from the posterior distribution of the parameters of the fitted model using Markov chain Monte Carlo methods; see text for details.
Figure 2.
Figure 2.
The relationships with climate classification for (a) RGR, (b) seed mass, (c) pot volume and (d) duration. In all cases p < 0.0001, using p-values generated using Markov chain Monte Carlo methods; see text for details.
Figure 3.
Figure 3.
Histogram of seed mass, subdivided into (a) forbs, (b) graminoids, (c) shrubs and (d) trees (p < 0.0001); p-value generated using Markov chain Monte Carlo methods, see text for details.
Figure 4.
Figure 4.
(a) Relationship between RGR and seed mass. Herb, black; woody, grey. The solid lines use the fixed effects from the final mixed-effects model (model 6, table 1). (b) Study-specific slopes for the log(RGR)versus log (seed mass) regressions.
See this image and copyright information in PMC

References

    1. Poorter H, Remkes C. 1990. Leaf-area ratio and net assimilation rate of 24 wild species differing in relative growth rate. Oecologia 83, 553–55910.1007/bf00317209 (doi:10.1007/bf00317209) - DOI - DOI - PubMed
    1. Hunt R, Cornelissen JHC. 1997. Components of relative growth rate and their interrelations in 59 temperate plant species. New Phytol. 135, 395–41710.1046/j.1469-8137.1997.00671.x (doi:10.1046/j.1469-8137.1997.00671.x) - DOI - DOI
    1. Grime JP, Hunt R. 1975. Relative growth-rate: its range and adaptive significance in a local flora. J. Ecol. 63, 393–42210.2307/2258728 (doi:10.2307/2258728) - DOI - DOI
    1. Grime JP. 1977. Evidence for existence of 3 primary strategies in plants and its relevance to ecological and evolutionary theory. Am. Nat. 111, 1169–119410.1086/283244 (doi:10.1086/283244) - DOI - DOI
    1. Grime JP. 2002. Plant strategies, vegetation processes, and ecosystem properties, 2nd edn Chichester, UK: John Wiley & Sons Ltd

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