The scaling of leaf area and mass: the cost of light interception increases with leaf size

Abstract

For leaves, the light-capturing surface area per unit dry mass investment (specific leaf area, SLA) is a key trait from physiological, ecological and biophysical perspectives. To address whether SLA declines with leaf size, as hypothesized due to increasing costs of support in larger leaves, we compiled data on intraspecific variation in leaf dry mass (LM) and leaf surface area (LA) for 6334 leaves of 157 species. We used the power function LM=alpha LAbeta to test whether, within each species, large leaves deploy less surface area per unit dry mass than small leaves. Comparing scaling exponents (beta) showed that more species had a statistically significant decrease in SLA as leaf size increased (61) than the opposite (7) and the average beta was significantly greater than 1 (betamean=1.10, 95% CI 1.08-1.13). However, scaling exponents varied markedly from the few species that decreased to the many that increased SLA disproportionately fast as leaf size increased. This variation was unrelated to growth form, ecosystem of origin or climate. The average within-species tendency found here (allometric decrease of SLA with leaf size, averaging 13%) is in accord with concurrent findings on global-scale trends among species, although the substantial scatter around the central tendency suggests that the leaf size dependency does not obligately shape SLA. Nonetheless, the generally greater mass per unit leaf area of larger than smaller leaves directly translates into a greater cost to build and maintain a unit of leaf area, which, all else being equal, should constrain the maximum leaf size displayed.

Biotic and abiotic variables influencing plant litter breakdown in streams: a global study

“…We assessed leaf quality by using the mean SLA, which is the ratio of leaf area (cm 2 ) to leaf dry mass (g). SLA is a key ecological and physiological plant trait [44] that often correlates with leaf toughness, nutrient concentration and breakdown rate [45,46]. To measure SLA, we scanned 20 leaves of each plant species, estimated their areas with IMAGEJ 10.2, dried them to constant mass and weighed them to the nearest 0.1 mg. We then calculated the mean SLA at each site.…”

Testing the generality of the ‘leafing intensity premium’ hypothesis in temperate broad-leaved forests: a survey of variation in leaf size within and between habitats

“…This literature indicates that leaf size tends to decline with increasing elevation (Givnish 1984;McDonald et al 2003), decreasing mean annual temperature (Givnish 1984;McDonald et al 2003;Wolfe 1995), decreasing mean annual rainfall (Givnish 1984;McDonald et al 2003;Wolfe 1995), and decreasing soil fertility (McDonald et al 2003). Leaf size can also vary across several orders of magnitude within individual plant communities (Givnish 1984;Milla and Reich 2007;Li et al 2008). …”

Geometrical constraints in the scaling relationships between genome size, cell size and cell cycle length in herbaceous plants

“…Although scaling relationships are common in the biological world and have been extensively studied [32][33][34][35][36][37][38], only scant attention has been paid to the scaling of GS with other plant traits. In an early study, Baetcke et al [39] found that the slope of the interspecific relationship between GS and nuclear volume is approximately 1 (i.e.…”