نتایج جستجو برای: hydraulic resistance
تعداد نتایج: 402559 فیلتر نتایج به سال:
The deposition of the instantaneously released sediment into a gravel matrix and the hydraulic resistance induced by the rapid siltation are investigated herein. The experimental results reveal that the depositional patterns of the sediment are governed by the gravel-sediment size ratio, the amount of sediment released, and the seepage flowrate. The observations also indicate that the stable st...
The specification of flow resistance is central to both simple and sophisticated hydraulic analyses. Yet it remains encumbered with the greatest level of uncertainty of all hydraulic parameters; despite over a century of field and flume experimentation. The selection of resistance coefficients for natural rivers remains more an empirical art than a matter of implementing robust scientifically v...
Although climate change will alter both soil water availability and evaporative demand, our understanding of how future climate conditions will alter tree hydraulic architecture is limited. Here, we demonstrate that growth at elevated temperatures (ambient +5 °C) affects hydraulic traits in seedlings of the deciduous boreal tree species Populus tremuloides, with the strength of the effect varyi...
During vessel evolution in angiosperms, scalariform perforation plates with many slit-like openings transformed into simple plates with a single circular opening. The transition is hypothesized to have resulted from selection for decreased hydraulic resistance. Previously, additional resistivity of scalariform plates was estimated to be small – generally 10% or less above lumen resistivity – ba...
BACKGROUND AND AIMS The co-occurring of evergreen and deciduous angiosperm trees in Asian tropical dry forests on karst substrates suggests the existence of different water-use strategies among species. In this study it is hypothesized that the co-occurring evergreen and deciduous trees differ in stem hydraulic traits and leaf water relationships, and there will be correlated evolution in droug...
Plant xylem must balance efficient delivery of water to the canopy against protection from air entry into the conduits via air-seeding. We investigated the relationship between tracheid allometry, end wall pitting, safety from air-seeding, and the hydraulic efficiency of conifer wood in order to better understand the trade-offs between effective transport and protection against air entry. Root ...
In the sieve elements (SEs) of the phloem, carbohydrates are transported throughout the whole plant from their site of production to sites of consumption or storage. SE structure, especially of the pore-rich end walls, has a direct effect on translocation efficiency. Differences in pore size and other features were interpreted as an evolutionary trend towards reduced hydraulic resistance. Howev...
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