Abstract Across plant species, leaves vary enormously in their size and venation architecture, of which one major function is to replace water lost transpiration. The leaf hydraulic conductance (K leaf) represents the capacity transport system deliver water, allowing stomata remain open for photosynthesis. Previous studies showed that K relates vein density (vein length per area). Additionally, architecture determines sensitivity damage; severing midrib caused gas exchange decline, with...

Leaf size and venation show remarkable diversity across dicotyledons, are key determinants of plant adaptation in ecosystems past present. Here we present global scaling relationships traits with leaf size. Across a new database for 485 globally distributed species, larger leaves had major veins diameter, but lower length per area, whereas minor vein were independent These allow estimation intact from fragments, to improve hindcasting climate biodiversity fossil remains. The can be explained...

Summary 1. Across plant species, drought tolerance and distributions with respect to water availability are strongly correlated two physiological traits, the leaf potential at wilting, that is, turgor loss point (π tlp ), cell solute full hydration, osmotic o ). We present methods determine these parameters 30 times more rapidly than standard pressure–volume (p–v) curve approach, making feasible community‐scale studies of tolerance. 2. optimized existing for measurements π using...

Leaf hydraulic supply is crucial to maintaining open stomata for CO2 capture and plant growth. During drought-induced dehydration, the leaf conductance (K leaf) declines, which contributes stomatal closure and, eventually, death. Previous studies have tended attribute decline of K embolism in vein xylem. We visualized at high resolution quantified experimentally vulnerability xylem outside-xylem pathways modeled their respective influences on water transport. Evidence from all approaches...

Abstract Leaf shrinkage with dehydration has attracted attention for over 100 years, especially as it becomes visibly extreme during drought. However, little been known of its correlation physiology. Computer simulations the leaf hydraulic system showed that a reduction conductance mesophyll pathways outside xylem would cause strong decline (K leaf). For 14 diverse species, we tested hypothesis (i.e. in whole leaf, cell and airspace thickness, area) is associated K at declining water...

Leaves are arguably the most complex and important physicobiological systems in ecosphere. Yet, water transport outside leaf xylem remains poorly understood, despite its impacts on stomatal function photosynthesis. We applied anatomical measurements from 14 diverse species to a novel model of flow an areole (the smallest region bounded by minor veins) predict impact variation across outside-xylem hydraulic conductance (K ox). Several predictions verified previous correlational studies: (1)...

Stomata, the microvalves on leaf surfaces, exert major influences across scales, from plant growth and productivity to global carbon water cycling. Stomatal opening enables photosynthesis, use, whereas survival of drought depends stomatal closure. Here we report that function is constrained by a safety-efficiency trade-off, such species with greater conductance under high availability (gmax) show sensitivity closure during dehydration, i.e., higher potential at which reduced 50% (Ψgs50). The...

Abstract Leaf dry mass per unit leaf area (LMA) is a central trait in ecology, but its anatomical and compositional basis has been unclear. An explicit mathematical physical framework for quantifying the cell tissue determinants of LMA will enable tests their influence on species, communities ecosystems. We present an approach to explaining from numbers, dimensions densities cells tissues, which provided unprecedented explanatory power 11 broadleaved woody angiosperm species diverse (33–262...

Summary Given increasing water deficits across numerous ecosystems world‐wide, it is urgent to understand the sequence of failure leaf function during dehydration. We assessed dehydration‐induced losses rehydration capacity and maximum quantum yield photosystem II ( F v / m ) in leaves 10 diverse angiosperm species, tested when these occurred relative turgor loss, declines stomatal conductance g s , hydraulic K including xylem outside pathways for same study plants. resolved sequences...

Leaf hydraulic conductance (Kleaf) is a major determinant of photosynthetic rate in well-watered and drought-stressed plants. Previous work assessed the decline Kleaf with decreasing leaf water potential (Ψleaf), most typically using rehydration kinetics methods, found that species varied shape their vulnerability curve, correlated other functional traits drought sensitivity. These findings were tested extended, new steady-state evaporative flux method under high irradiance, function for...

Ecosystems worldwide are facing increasingly severe and prolonged droughts during which hydraulic failure from drought-induced embolism can lead to organ or whole plant death. Understanding the determinants of xylem across species is especially critical in leaves, engines growth. If vulnerability segmentation hypothesis holds within higher order veins that most terminal system should be more susceptible protect rest water transport system. Increased would also consistent with these...

ABSTRACT The leaf is a hydraulic bottleneck, accounting for large part of plant resistance. Thus, the conductance ( K ) key importance in determining stomatal g s and rates gas exchange. Previous studies showed that dynamic with water status irradiance. For four species, we tested combined impacts these factors on . We determined responses to declining potential Ψ under low high irradiance (<6 >900 µ mol photons m −2 −1 photosynthetically active radiation, respectively). hypothesized...

The sites of evaporation within leaves are unknown, but they have drawn attention for decades due to their perceived implications many factors, including patterns leaf isotopic enrichment, the maintenance mesophyll water status, stomatal regulation, and interpretation measured hydraulic conductances. We used a spatially explicit model coupled heat transport outside xylem, MOFLO 2.0, map distribution net across tissues in relation anatomy environmental parameters. Our results corroborate...

Summary Leaf hydraulic conductance ( K leaf ) quantifies the capacity of a to transport liquid water and is major constraint on light‐saturated stomatal g s photosynthetic rate A max ). Few studies have tested plasticity anatomy across growth light environments. These provided conflicting results. The Hawaiian lobeliads are an excellent system examine plasticity, given striking diversity in regimes they occupy, their correspondingly wide range , allowing maximal carbon gain for success We...

Summary Clarifying the coordination of leaf hydraulic traits with gas exchange across closely‐related species adapted to varying rainfall can provide insights into plant habitat distribution and drought adaptation. The conductance ( K ), stomatal g s net assimilation A vein embolism abscisic acid (ABA) concentration during dehydration were quantified, as well pressure–volume curve anatomy in 10 Caragana a range mean annual precipitation (MAP) conditions growing common garden. We found...

Grasses are exceptionally productive, yet their hydraulic adaptation is paradoxical. Among C

ABSTRACT Previous studies have shown a rapid enhancement in leaf hydraulic conductance ( K ) from low to high irradiance (from <10 >1000 µ mol photons m −2 s −1 ), using the high‐pressure flow meter (HPFM), for 7 of 14 tested woody species. However, theoretical suggestions been made that this response might arise as an artifact HPFM. We light six evergreen species refined versions rehydration kinetics method (RKM) and evaporative flux (EFM). found new evidence rapid, 60% 100% increase...