A clear trade‐off between leaf hydraulic efficiency and safety in an aridland shrub during regrowth

2021 ◽  
Author(s):  
Guang‐Qian Yao ◽  
Zheng‐Fei Nie ◽  
Yuan‐Yuan Zeng ◽  
Muhammad Waseem ◽  
Md. Mahadi Hasan ◽  
...  
Keyword(s):  
Hydraulic Efficiency ◽  
Trade Off

scholarly journals The roles of conduit redundancy and connectivity in xylem hydraulic functions

2020 ◽  
Author(s):  
Assaad Mrad ◽  
Daniel M Johnson ◽  
David M Love ◽  
Jean-Christophe Domec
Keyword(s):  
Graph Theory ◽  
Water Potential ◽  
Percolation Theory ◽  
Water Movement ◽  
Xylem Sap ◽  
Woody Species ◽  
Flowering Plants ◽  
Hydraulic Efficiency ◽  
Trade Off ◽  
Network Characteristics

Wood anatomical traits shape a xylem segment's hydraulic efficiency and embolism spread resistance due to declining water potential. Because xylem sap is in a metastable state, gas embolisms might spread within the sapwood conduits as water potential declines, inhibiting water movement. It has been known for decades that variations in conduit connectivity play a role in altering xylem hydraulics. However, evaluating the precise effect of conduit connectivity on hydraulic efficiency and embolism spread resistance has been elusive. Using graph theory, percolation theory, and computational modeling, we show that increases in conduit connectivity improves resistance to embolism spread in certain flowering plants without compromising hydraulic efficiency. The influence of conduit connectivity might explain in part why the hypothesis of the 'safety-efficiency' trade-off is weak among woody species with different xylem network characteristics. Overall, knowing how xylem network measures influence segment hydraulics is necessary to generalize trends linking anatomy and hydraulic function among woody species.

scholarly journals The hydraulic efficiency–safety trade‐off differs between lianas and trees

Ecology ◽  
2019 ◽  
Vol 100 (5) ◽  
pp. e02666 ◽  
Author(s):  
Masha T. Sande ◽  
Lourens Poorter ◽  
Stefan A. Schnitzer ◽  
Bettina M. J. Engelbrecht ◽  
Lars Markesteijn
Keyword(s):  
Hydraulic Efficiency ◽  
Trade Off

scholarly journals Hydraulic traits are coordinated with maximum plant height at the global scale

2019 ◽  
Vol 5 (2) ◽  
pp. eaav1332 ◽  
Author(s):  
Hui Liu ◽  
Sean M. Gleason ◽  
Guangyou Hao ◽  
Lei Hua ◽  
Pengcheng He ◽  
...  
Keyword(s):  
Plant Height ◽  
Hydraulic Resistance ◽  
Water Availability ◽  
Woody Species ◽  
Global Scale ◽  
Hydraulic Efficiency ◽  
Trade Off ◽  
Species Sorting ◽  
Hydraulic Safety ◽  
The Relationship

Water must be transported long distances in tall plants, resulting in increasing hydraulic resistance, which may place limitations on the maximum plant height (Hmax) in a given habitat. However, the coordination of hydraulic traits with Hmax and habitat aridity remains poorly understood. To explore whether Hmax modifies the trade-off between hydraulic efficiency and safety or how water availability might influence the relationship between Hmax and other hydraulic traits, we compiled a dataset including Hmax and 11 hydraulic traits for 1281 woody species from 369 sites worldwide. We found that taller species from wet habitats exhibited greater xylem efficiency and lower hydraulic safety, wider conduits, lower conduit density, and lower sapwood density, which were all associated with habitat water availability. Plant height and hydraulic functioning appear to represent a single, coordinated axis of variation, aligned primarily with water availability, thus suggesting an important role for this axis in species sorting processes.

scholarly journals Distinct xylem responses to acute vs prolonged drought in pine trees

2020 ◽  
Vol 40 (5) ◽  
pp. 605-620 ◽  
Author(s):  
Marceau Guérin ◽  
Georg von Arx ◽  
Dario Martin-Benito ◽  
Laia Andreu-Hayles ◽  
Kevin L Griffin ◽  
...  
Keyword(s):  
Water Stress ◽  
Soil Drought ◽  
Hydraulic Efficiency ◽  
Atmospheric Moisture ◽  
Water Addition ◽  
Trade Off ◽  
Xylem Structure ◽  
Plant Hydraulics ◽  
Growing Seasons ◽  
Prolonged Drought

Abstract Increasing dryness challenges trees’ ability to maintain water transport to the leaves. Most plant hydraulics models use a static xylem response to water stress. Yet, in reality, lower soil moisture and warmer temperatures during growing seasons feed back onto xylem development. In turn, adjustments to water stress in the newly built xylem influence future physiological responses to droughts. In this study, we investigate the annual variation of anatomical traits in branch xylem in response to different soil and atmospheric moisture conditions and tree stress levels, as indicated by seasonal predawn leaf water potential (ΨL,pd). We used a 6-year field experiment in southwestern USA with three soil water treatments applied to Pinus edulis Engelm trees—ambient, drought (45% rain reduction) and irrigation (15–35% annual water addition). All trees were also subject to a natural 1-year acute drought (soil and atmospheric) that occurred during the experiment. The irrigated trees showed only moderate changes in anatomy-derived hydraulic traits compared with the ambient trees, suggesting a generally stable, well-balanced xylem structure under unstressed conditions. The artificial prolonged soil drought increased hydraulic efficiency but lowered xylem construction costs and decreased tracheid implosion safety ((t/b)2), suggesting that annual adjustments of xylem structure follow a safety–efficiency trade-off. The acute drought plunged hydraulic efficiency across all treatments. The combination of acute and prolonged drought resulted in vulnerable and inefficient new xylem, disrupting the stability of the anatomical trade-off observed in the rest of the years. The xylem hydraulic traits showed no consistent direct link to ΨL,pd. In the future, changes in seasonality of soil and atmospheric moisture are likely to have a critical impact on the ability of P. edulis to acclimate its xylem to warmer climate. Furthermore, the increasing frequency of acute droughts might reduce hydraulic resilience of P. edulis by repeatedly creating vulnerable and less efficient anatomical structure.

A Flow-Preserving Algorithm for the Time-Cost Trade-Off Problem

1982 ◽  
Vol 14 (2) ◽  
pp. 109-113 ◽  
Author(s):  
Suleyman Tufekci
Keyword(s):  
Time Cost ◽  
Trade Off

Dual Goals for Speed and Accuracy on the Same Performance Task

2012 ◽  
Vol 11 (3) ◽  
pp. 118-126 ◽  
Author(s):  
Olive Emil Wetter ◽  
Jürgen Wegge ◽  
Klaus Jonas ◽  
Klaus-Helmut Schmidt
Keyword(s):  
Memory Scanning ◽  
Performance Task ◽  
Performance Tasks ◽  
Trade Off ◽  
Test Experiment ◽  
Trade Offs ◽  
New Finding ◽  
Sternberg Paradigm ◽  
Speed Accuracy ◽  
Speed And Accuracy

In most work contexts, several performance goals coexist, and conflicts between them and trade-offs can occur. Our paper is the first to contrast a dual goal for speed and accuracy with a single goal for speed on the same task. The Sternberg paradigm (Experiment 1, n = 57) and the d2 test (Experiment 2, n = 19) were used as performance tasks. Speed measures and errors revealed in both experiments that dual as well as single goals increase performance by enhancing memory scanning. However, the single speed goal triggered a speed-accuracy trade-off, favoring speed over accuracy, whereas this was not the case with the dual goal. In difficult trials, dual goals slowed down scanning processes again so that errors could be prevented. This new finding is particularly relevant for security domains, where both aspects have to be managed simultaneously.

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