Interspecific Variation in RGR and the Underlying Traits among 24 Grass Species Grown in Full Daylight

Abstract

A growth analysis was conducted with 24 central European grass species in full daylight to test whether traits underlying interspecific variation in relative growth rate (RGR) are the same in full daylight as they are at lower light, and whether this depends on the ecological characteristics of the studied species, i.e., their requirements with respect to nutrient and light availability. In contrast to studies with herbaceous species at lower light, net assimilation rate (NAR) contributed more than leaf area ratio (LAR) or specific leaf area (SLA) to interspecific variation in RGR. This was associated with a larger interspecific variation in NAR than found in experiments with lower light. Without the two most shade‐tolerant species, however, the contribution of LAR and its components to interspecific variation in RGR was similar or even higher than that of NAR. Leaf dry matter content correlated negatively with RGR and was the only component of LAR contributing in a similar manner to variation in LAR and RGR. There was a positive correlation between NAR and biomass allocation to roots, which may be a result of nutrient‐limited growth. RGR correlated negatively with biomass allocation to leaves. Leaf thickness did not correlate with RGR, as the positive effect of thin leaves was counterbalanced by their lower NAR. Low inherent RGR was associated with species from nutrient‐poor or shady habitats. Different components constrained growth for these two groups of species, those from nutrient‐poor habitats having high leaf dry matter content, while those from shady habitats had thin leaves with low NAR.

Growth Analysis of Potted Seedlings of Satsuma Mandarin (<i>Citrus unshiu</i> Marc.) under Different Light Conditions and Air Temperatures

“…dominant (Lambers and Poorter, 1992;Modrzyński et al, 2015;Poorter and Remkes, 1990;Rees et al, 2010;Reich et al, 1992 andWalters et al, 1993;Westoby, 1999, 2000) and NAR-dominant (Huante and Rincon, 1998;Huante et al, 1995;Poorter, 1999;Ryser and Wahl, 2001;Saverimuttu and Westoby, 1996;Shipley, 2006;Taub, 2002), and LMR hardly contributes to RGR (Shipley, 2006). Our results showed three key points.…”

What determines interspecific variation in relative growth rate of Eucalyptus seedlings?

“…Veenendaal et al 1996;Ryser and Wahl 2001;Shipley 2002). Several studies have shown that relationships among growth parameters depend on the species chosen, in particular, whether variation in RGR is due to variation in shade tolerance or in tolerance of water and/or nutrient stress Ryser and Wahl 2001).…”

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

“…The metaanalysis by Shipley [30] found that NAR was generally the best predictor of RGR, but that as light intensity decreased, the importance of NAR declined and the importance of SLA increased, at least in herbaceous species. The relationship between LMR and RGR is inconsistent, with many a non-significant relationships [31,32]. Therefore, explanations for the variance in RGR between growth forms using the components of RGR are currently contradictory and require further research using approaches that accounts for the effects of plant mass [33].…”