Leaf area, chlorophyll content, net CO(2) photoassimilation, and the partitioning of fixed carbon between leaf sucrose and starch and soluble protein were examined in Glycine max (L) Merr. cv Williams grown under three different nitrogen regimes. One group (Nod+/+) was inoculated with Bradyrhizobium and watered daily with a nutrient solution containing 6 millimolar NH(4)NO(3). A second set (Nod...

Leaf area index is one of the most important parameters in ecological and environmental studies. This paper presents a method for single leaf area measurement based on the counting of the leaf pixels in digital leaf image. Initially, the target leaf is put on a piece of white paper on which four endpoints of an equal-length and orthogonal cross are printed. A background color threshold is then ...

Evergreen oaks are an emblematic element of the Mediterranean vegetation and have a leaf phenotype that seems to have remained unchanged since the Miocene. We hypothesise that variation of the sclerophyll phenotype among Iberian populations of Quercus coccifera is partly due to an ulterior process of ecotypic differentiation. We analysed the genetic structure of nine Iberian populations using I...

Most terrestrial ecosystems are nitrogen (N)-limited. The elucidation of the multivariate relationships among environmental drivers, leaf morphological traits, and foliar N of dominant species which are critical to the functioning of forests remains a critical challenge for ecologists. We sampled leaves of Quercus wutaishanica across a broad natural gradient in the Loess Plateau, China, and emp...

Many biomechanical and theoretical studies have been based on the pipe-model theory, according to which a tree is regarded as an assemblage of pipes, each having the same amount of leaf area or leaf mass. However, the physiological mechanisms underlying the theory have not been extensively examined, particularly at the branch level. We analyzed how branches and trunks thickened in nine young Ac...

Foliage growth, mass- and area-based leaf nitrogen concentrations (Nm and N a) and specific leaf area (SLA) were surveyed during a complete vegetation cycle for two co-occurring savanna tree species: Crossopteryx febrifuga (Afzel. ex G. Don) Benth. and Cussonia arborea A. Rich. The study was conducted in the natural reserve of Lamto, Ivory Coast, on isolated and clumped trees. Leaf flush occurr...

Much attention has been paid to differences in leaf form and composition among vegetation types, but less to the frequently substantial variation within vegetation types. We focused on the extent to which correlations between variables are the same in both succulent-poor and succulent-rich vegetation in semi-arid SE Spain. Mean foliar [N] of perennials varied among species over a 5-fold range. ...