Leaf shrinkage with dehydration has attracted attention for over 100 years, especially as it becomes visibly extreme during drought. However, little has been known of its correlation with physiology. Computer simulations of the leaf hydraulic system showed that a reduction of hydraulic conductance of the mesophyll pathways outside the xylem would cause a strong decline of leaf hydraulic conduct...

We investigated how leaf hydraulic conductance (K(leaf)) of loblolly pine trees is influenced by soil nitrogen amendment (N) in stands subjected to ambient or elevated CO(2) concentrations (CO(2)(a) and CO(2)(e), respectively). We also examined how K(leaf) varies with changes in reference leaf water potential (Psi(leaf-ref)) and stomatal conductance (g(s-ref)) calculated at vapour pressure defi...

For an integer k, a tree T is a k-leaf root of a finite simple undirected graph G = (V,E) if the set of leaves of T is the vertex set V of G and for any two vertices x, y ∈ V , x 6= y, xy ∈ E if and only if the distance of x and y in T is at most k. Then graph G is a k-leaf power if it has a k-leaf root. G is a leaf power if it is a k-leaf power for some k. This notion was introduced and studie...

Chlorophyll meters are widely used to guide nitrogen (N) management by monitoring leaf N status in agricultural systems, but the effects of environmental factors and leaf characteristics on leaf N estimations are still unclear. In the present study, we estimated the relationships among SPAD readings, chlorophyll content and leaf N content per leaf area for seven species grown in multiple enviro...

Earth harbors a highly diverse array of plant leaf forms. A well-known pattern linking diverse leaf forms with their photosynthetic function across species is the global leaf economics spectrum (LES). However, within homogeneous plant functional groups such as tropical woody angiosperms or temperate deciduous woody angiosperms, many species can share a similar position in the LES but differ in ...

Physiological effects of different nitrate applications were studied using the C(4) plant, Amaranthus powellii Wats. Plants were grown in a controlled environment chamber and watered daily with nutrient solutions containing 45, 10, 5, or 1 millimolar nitrate. Chloride and sulfate were used to keep the cation and phosphate concentrations constant. Total leaf nitrogen concentration, chlorophyll c...

1. Secondary colonization of leaf shelters constructed by caterpillars has been reported from a number of systems. Both the mechanism (larval or adult movement vs. oviposition) and the cues used by arthropods in locating leaf shelters, however, have received little attention. 2. Artificial leaf shelters (i.e. leaf ties or pairs of leaves clipped together to form sandwiches) were constructed on ...

Motivated by the problem of reconstructing evolutionary history, Nishimura et al. defined k-leaf powers as the class of graphs G = (V,E) which has a k-leaf root T , i.e., T is a tree such that the vertices of G are exactly the leaves of T and two vertices in V are adjacent in G if and only if their distance in T is at most k. It is known that leaf powers are chordal graphs. Brandstädt and Le pr...

rounded leaf tip. The leaf collar marks the junction of the leaf blade and sheath and appears when the leaf is fully developed. Each leaf sheath originates at its own node on the plant stalk. The sheath surrounds and strengthens the stalk (culm). The flag leaf is the last to emerge on the plant and is considerably smaller than the other leaves. The panicle (head) emerges from the flag leaf shea...

Much of the research on African American college students at predominantly White institutions (PWIs) indicates that African American students encounter difficulty in social and academic integration. In much of this research, it is assumed, explicitly or implicitly, that African American students experience lower adjustment and performance in these settings due to fewer socioeconomic resources i...