scholarly journals The trade-off between safety and efficiency in hydraulic architecture in 31 woody species in a karst area

2011 ◽  
Vol 31 (8) ◽  
pp. 865-877 ◽  
Author(s):  
D.-Y. Fan ◽  
S.-L. Jie ◽  
C.-C. Liu ◽  
X.-Y. Zhang ◽  
X.-W. Xu ◽  
...  
2008 ◽  
Vol 102 (4) ◽  
pp. 623-629 ◽  
Author(s):  
Dongmei Yang ◽  
Guoyong Li ◽  
Shucun Sun
Keyword(s):  

2017 ◽  
Vol 6 (2) ◽  
pp. 19-29
Author(s):  
G. Todou ◽  
M. Hassan ◽  
Akamba Ze ◽  
D. Kombo ◽  
S. Machewere ◽  
...  

 The Northern Regions of Cameroon belong to sudano-zambesian region. In these regions, woody species are scarce compared to Guinean-Congolese Region and they undergo the human pressure like abusive exploitation of plants. In order to contribute to valorization of phytogenetic resources and contribute to struggle desert progression in sahelian region, a study on plants diversity which are used to produce charcoal and its trade-off was carried out in Far-North Region of Cameroon. Census of plants species was made on the basis of semi-structured surveys through the producers of charcoal and identification of tree trunks on the sites of charcoal production. Data of trade of charcoal was collected by direct observation and a semi-structured survey questionnaire in Maroua. In total, 25 species grouped in 17 genera and 8 families have been recorded. Acacia and Combretum were the richest genera with four species each. They were quoted as multipurpose species which can be used elsewhere as fruits, timbers, medicinal plants or essential oils and exudates. In Maroua almost, 98 % of households use charcoal for heating. In the absence of the charcoal, up to 60 % of those use firewood, 18.46 % use domestic gas and 18.46% use kerosene. Because of poverty and unemployment, people of primary education are mostly charcoal sellers.  INTERNATIONAL JOURNAL OF ENVIRONMENTVolume-6, Issue-2, Mar-May 2017, Page: 19-29


2020 ◽  
Vol 229 (3) ◽  
pp. 1354-1362
Author(s):  
Giacomo Puglielli ◽  
Michael J. Hutchings ◽  
Lauri Laanisto

2004 ◽  
Vol 52 (4) ◽  
pp. 509 ◽  
Author(s):  
Kate McClenahan ◽  
Catriona Macinnis-Ng ◽  
Derek Eamus

Seasonal comparisons of leaf water potential, root biomass, hydraulic architecture, xylem embolism and xylem dimensions were made for eight woody species in four diverse habitats (mangroves, coastal heathland, ridge-top woodland and river-flat woodland). In most comparisons, pre-dawn and minimum leaf water potentials were lower in winter than in summer, a result attributed to lower rainfall and a smaller root biomass in winter than in summer. Branch hydraulic conductivities (per unit transverse area, sapwood area or leaf area) were generally larger in summer than in winter across all species in all habitats. An inverse relationship between Huber value and conductivity was observed across all four habitats. Increased solar radiation and evaporative demand in the summer was associated with an increased percentage loss of xylem conductance arising from embolism, compared with winter. These results are discussed in the context of patterns and relationships among water relations, microclimate and hydraulic architecture.


2020 ◽  
Author(s):  
Assaad Mrad ◽  
Daniel M Johnson ◽  
David M Love ◽  
Jean-Christophe Domec

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.


2020 ◽  
Vol 44 (10) ◽  
pp. 995-1006
Author(s):  
Dan MO ◽  
Zhen-Meng WANG ◽  
You-Lu ZUO ◽  
Shuang XIANG ◽  
Keyword(s):  

2008 ◽  
Vol 20 (3) ◽  
pp. 233-245 ◽  
Author(s):  
Sandra J. Bucci ◽  
Fabian G. Scholz ◽  
Guillermo Goldstein ◽  
Frederick C. Meinzer ◽  
Augusto C. Franco ◽  
...  

We determined adjustments in physiology and morphology that allow Neotropical savanna trees from central Brazil (Cerrado) to avoid water deficits and to maintain a nearly constant internal water balance despite seasonal changes in precipitation and air saturation deficit (D). Precipitation in the study area is highly seasonal with about five nearly rainless months during which D is two fold higher compared to wet season values. As a consequence of the seasonal fluctuations in rainfall and D, soil water potential changes substantially in the upper 100 cm of soil, but remains nearly constant below 2 m depth. Hydraulic architecture and water relations traits of Cerrado trees adjusted during the dry season to prevent increasing water deficits and insure homeostasis in minimum leaf water potential ψL and in total daily water loss per plant (isohydry). The isohydric behavior of Cerrado trees was the result of a decrease in total leaf surface area per tree, a strong stomatal control of evaporative losses, an increase in leaf-specific hydraulic conductivity and leaf hydraulic conductance and an increase in the amount of water withdrawn from internal stem storage, during the dry season. Water transport efficiency increased in the same proportion in leaves and terminal stems during the dry season. All of these seasonal adjustments were important for maintaining ψL above critical thresholds, which reduces the rate of embolism formation in stems and help to avoid turgor loss in leaf tissues still during the dry season. These adjustments allow the stems of most Cerrado woody species to operate far from the point of catastrophic dysfunction for cavitation, while leaves operate close to it and experience embolism on a daily basis, especially during the dry season.


2019 ◽  
Vol 5 (2) ◽  
pp. eaav1332 ◽  
Author(s):  
Hui Liu ◽  
Sean M. Gleason ◽  
Guangyou Hao ◽  
Lei Hua ◽  
Pengcheng He ◽  
...  

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.


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