Structural and defensive roles of angiosperm leaf venation network reticulation across an Andes–Amazon elevation gradient

Abstract

The network of minor veins of angiosperm leaves may include loops (reticulation). Variation in network architecture has been hypothesized to have hydraulic and also structural and defensive functions. We measured venation network trait space in eight dimensions for 136 biomass‐dominant angiosperm tree species along a 3,300 m elevation gradient in southeastern Peru. We then examined the relative importance of multiple ecological and evolutionary predictors of reticulation. Variation in minor venation network reticulation was constrained to three axes. These axes described reconnecting vs. branching veins, elongated vs. compact areoles compact vs. elongated and low vs. high‐density veins. Variation in the first two axes was predicted by traits related to mechanical strength and secondary compounds, and in the third axis by site temperature. Synthesis. Defensive and structural factors primarily explain variation in multiple axes of reticulation, with a smaller role for climate‐linked factors. These results suggest that venation network reticulation may be determined more by species interactions than by hydraulic functions.

Secondary metabolites have more influence than morphophysiological traits on litter decomposability across genotypes of Arabidopsis thaliana

“…PCs) directly causes a 1‐SD increase in the response variable (i.e. LMR), after accounting for any other predictor variables (Blonder et al ., ). We followed the same procedure for climate PCs.…”

Multiple components of plant diversity loss determine herbivore phylogenetic diversity in a subtropical forest experiment

“…However, previous research in our study region frequently found strong positive relationships between LDMC and leaf herbivory (Schuldt, Assmann, et al, ; Schuldt, Baruffol, et al, ; Schuldt et al, ), possibly because many of the dominant leaf chewers might be adapted to coping with robust leaves in areas where trees with such leaves are common (Pérez‐Harguindeguy et al, ). Such a positive relationship might reflect compensatory feeding to make up for low nutrient contents (see Schuldt et al, ), or correlation with unmeasured traits that affect herbivory, such as secondary plant metabolites (Blonder et al, ). Carbon concentrations and the C:N ratio of leaves are related to palatability, and low C:N ratios in particular have commonly been found to promote herbivory (Pérez‐Harguindeguy et al, ; Poorter et al, ).…”

Automated and accurate segmentation of leaf venation networks via deep learning

“…A 1 cm 2 sample was cut from the middle of the lamina, excluding any primary veins, chemically cleared, stained, and slide-mounted following standard protocols (Pérez-Harguindeguy et al, 2013;Blonder et al, 2018). Each sample was imaged using a compound microscope (Olympus, BX43) with 2x apochromat objective and an Olympus SC100 color camera (3840 x 2748 pixel resolution).…”

“…Here, we also used HLD to determine scaling relationships, but retained a set of more conventional metrics to compare network architecture across scales. These multi-scale statistics may provide additional insights into how network architecture influences transport, support, defense, embolism resistance, and resilience to herbivory (Sack et al, 2008;Katifori et al, 2010;Brodribb et al, 2016;Blonder et al, 2018).…”

“…Some venation networks contain freely-ending veins (FEVs) that do not form anastomoses with other veins, but which may help with efficient supply of water (Fiorin et al, 2016), or possibly transport of sugars (Carvalho et al, 2018). As such, density estimates of branching end-points or areole perimeter/area ratios (Kang & Dengler, 2004;Blonder et al, 2018) are also useful. Finally, , the distribution of branching angles and radius or length ratios at vein branching points (Bohn et al, 2002), feed into theories and models of flow efficiency, network development and architecture (Pelletier & Turcotte, 2000;Price et al, 2012;.…”