Optimal photosynthetic use of light by tropical tree crowns achieved by adjustment of individual leaf angles and nitrogen content

Abstract

The results suggest that canopy tree leaves in this tropical forest optimize photosynthetic use of PPFD rather than N per se. Tropical tree canopies then can be considered simple 'big-leaves' in which all constituent 'small leaves' use PPFD with the same photosynthetic efficiency.

Circumboreal Gradients in Plant Species and Functional Types

“…More recent evidence suggests however, that such traits may not operate in functional isolation, their performance being modulated by other important elements such as leaf inclination, longevity and life form. One may therefore speculate that, depending on their composition, trait assemblages will be subject to complex functional feedbacks that will vary according to environment and evolutionary background , Posada et al 2009, Gillison 2012). The challenge is to identify and combine functional traits in a way that can be applied meaningfully in science and in practice.…”

Optimisation of photosynthetic carbon gain and within-canopy gradients of associated foliar traits for Amazon forest trees

“…For example, it does not take into account effects of direct versus diffuse radiation (Buckley et al, 2002) and considers the forest canopy to consist only of one generic phenotype. This overlooks the clear intra-and inter-species variations in photosynthetic characteristics and associated leaf traits that clearly occur, especially for tropical forest canopies (Domingues et al, 2005;Fyllas et al, 2009), along with substantial within and between-tree variations in leaf angle and size (Kitajima et al, 2005;Poseda et al, 2009) which should also give rise to attendant variations in k I . The model simulations also involve some simplistic assumptions regarding leaf lifetimes and associated annual construction costs of the photosynthetic machinery (Sect.…”

“…Also, as many studies have reported Q z /Q 0 (see Eq. A2) rather than cumulative leaf area index, it was often necessary to make assumptions about k I , for example as in Meir et al (2002) -this being taken as uniform throughout the canopy, although it may also be the case that leaf angles, and hence k I , may vary with canopy depth (Poseda et al, 2009). The required assumptions for each study are listed in the right hand column of Table S1 (Supplementary Information: http://www.biogeosciences.net/7/1833/ bg-7-1833, and it is because of the considerable uncertainties involved with the estimates of both V max(0) and/or k V that we have used a robust high breakpoint rank regression technique (Chang et al, 1999) to estimate the slope and its significance for the relationship shown in Fig.…”

Fotosíntesis de plántulas de <i>Otoba novogranatensis</i> (Myristicaceae) y <i>Ruagea glabra</i> (Meliaceae) en pastizales abandonados, bosques secundarios y hábitats de plantaciones en Costa Rica

“…Some aspects of the A-Q response (i.e. less-negative R d , lower LCP, and higher A max ) were consistent with higher photosynthetic capacity for seedlings from the tree plantations in comparison to pasture and secondary forest habitats ( Riddoch et al 1991, Johnson et al 1997, Ellis et al 2000, Posada et al 2009). When R d and A max are considered together, seedlings of both species in the pasture habitats had a lower net C budget compared to leaves from plants in plantations and secondary forests.…”