Leaf Vein Traits Research Articles

Leaf hydraulic conductance varies with vein anatomy across Arabidopsis thaliana wild-type and leaf vein mutants.

Leaf venation is diverse across plant species and has practical applications from paleobotany to modern agriculture. However, the impact of vein traits on plant performance has not yet been tested in a model system such as Arabidopsis thaliana. Previous studies analysed cotyledons of A. thaliana vein mutants and identified visible differences in their vein systems from the wild type (WT). We measured leaf hydraulic conductance (Kleaf ), vein traits, and xylem and mesophyll anatomy for A. thaliana WT (Col-0) and four vein mutants (dot3-111 and dot3-134, and cvp1-3 and cvp2-1). Mutant true leaves did not possess the qualitative venation anomalies previously shown in the cotyledons, but varied quantitatively in vein traits and leaf anatomy across genotypes. The WT had significantly higher mean Kleaf . Across all genotypes, there was a strong correlation of Kleaf with traits related to hydraulic conductance across the bundle sheath, as influenced by the number and radial diameter of bundle sheath cells and vein length per area. These findings support the hypothesis that vein traits influence Kleaf , indicating the usefulness of this mutant system for testing theory that was primarily established comparatively across species, and supports a strong role for the bundle sheath in influencing Kleaf .

Influences of environmental factors on leaf morphology of Chinese jujubes.

Rainfall and temperature are the primary limiting factors for optimum quality and yield of cultivated jujube (Ziziphus jujuba Mill.). Adaptation to arid and cool environments has been and remains an important goal of many jujube improvement programs. This study summarized the survey results of 116 Chinese jujube varieties grown at 33 sites in China. The objective was to identify the environmental factors that influence leaf morphology, and the implications for breeding and introduction of new jujube varieties. Jujube leaf morphological traits were evaluated for their potential relationships with mean annual temperature (MAT) and mean annual precipitation (MAP). The results showed that many leaf morphological traits had a strong linear relationship with local precipitation and temperature. Longer veins per unit area (VLA) and reduced leaf area and leaf perimeter were typical of arid areas. VLA was inversely related to MAT and MAP at the centers of origin of jujube. There was a positive relationship between leaf shape (perimeter2/area) and both MAT and MAP. These results indicated that leaf vein traits of Chinese jujubes might have resulted from their adaptation to environmental factors in the course of long-term evolution. Principal component analysis allocated the 116 jujube varieties to three different groups, differentiated on the basis of morphological and physiological leaf characteristics. Jujube varieties from the Hebei, Shandong, Henan, southern Shanxi and central Shaanxi provinces were closely related, as were varieties from northwest Shanxi and northeast Shaanxi provinces, and varieties from the Gansu and Ningxia provinces. These close relationships were partially attributed to the frequent exchanges of varieties within each group. Leaf venation characteristics might be used as reference indices for jujube variety introduction between different locations.

How do leaf veins influence the worldwide leaf economic spectrum? Review and synthesis

Leaf vein traits are implicated in the determination of gas exchange rates and plant performance. These traits are increasingly considered as causal factors affecting the 'leaf economic spectrum' (LES), which includes the light-saturated rate of photosynthesis, dark respiration, foliar nitrogen concentration, leaf dry mass per area (LMA) and leaf longevity. This article reviews the support for two contrasting hypotheses regarding a key vein trait, vein length per unit leaf area (VLA). Recently, Blonder et al. (2011, 2013) proposed that vein traits, including VLA, can be described as the 'origin' of the LES by structurally determining LMA and leaf thickness, and thereby vein traits would predict LES traits according to specific equations. Careful re-examination of leaf anatomy, published datasets, and a newly compiled global database for diverse species did not support the 'vein origin' hypothesis, and moreover showed that the apparent power of those equations to predict LES traits arose from circularity. This review provides a 'flux trait network' hypothesis for the effects of vein traits on the LES and on plant performance, based on a synthesis of the previous literature. According to this hypothesis, VLA, while virtually independent of LMA, strongly influences hydraulic conductance, and thus stomatal conductance and photosynthetic rate. We also review (i) the specific physiological roles of VLA; (ii) the role of leaf major veins in influencing LES traits; and (iii) the role of VLA in determining photosynthetic rate per leaf dry mass and plant relative growth rate. A clear understanding of leaf vein traits provides a new perspective on plant function independently of the LES and can enhance the ability to explain and predict whole plant performance under dynamic conditions, with applications towards breeding improved crop varieties.

Pattern of leaf vein density and climate relationship of Quercus variabilis populations remains unchanged with environmental changes

The leaf vein traits of plants result partially from adaptations to environmental factors during the long-term evolution. However, no general conclusion on the variation trend of the vein density along a climate gradient or the response of such vein density–climate relationship pattern to climate changes has been made. We examined the variations in leaf vein density and other leaf traits of oriental oak (Quercus variabilis) in 10 in situ populations (in situ populations) across temperate-subtropical biomes and the response of the leaf vein density to environmental changes in 7 populations grown in a common garden (garden populations). The results show that the minor vein density of the in situ populations (≥3rd order) significantly decreased with increasing latitude (r 2 = 0.44 and P = 0.04). This pattern remained unchanged for the garden populations (r 2 = 0.67 and P = 0.02). The minor vein densities of both the garden and in situ populations were positively correlated to the mean annual temperature (MAT) of the origins (r 2 = 0.66 and P = 0.03 for the garden populations; r 2 = 0.37 and P = 0.06 for the in situ populations), but their correlation to the mean annual precipitation (MAP) of the origins was not significant. Compared with the MAT and MAP, the vein density displayed a significantly lower correlation to climate variables in the current year or the current-year growing seasons. For the garden populations, the minor vein density significantly increased with leaf dry mass per area and decreased with petiole length and leaf length. These results imply that leaf vein density is genotypically fixed and is therefore not responsive to temporal changes in the growing conditions.