When tree stems are mechanically stimulated, a rapid long-distance signal is induced that slows down primary growth. An investigation was carried out to determine whether the signal might be borne by a mechanically induced pressure pulse in the xylem. Coupling xylem flow meters and pressure sensors with a mechanical testing device, the hydraulic effects of mechanical deformation of tree stem an...

Ions can enhance water flow through the xylem via changes in the hydraulic resistance at border pit membranes. Because flow between adjacent xylem vessels occurs primarily via bordered pit fields, it is hypothesized that xylem sap ion concentrations would affect lateral movement of water more than longitudinal flow. Using tomato as a model system, evidence is presented for ion-mediated changes ...

Measurements of diurnal diameter variations of the xylem and phloem are a promising tool for studying plant hydraulics and xylem-phloem interactions in field conditions. However, both the theoretical framework and the experimental verification needed to interpret phloem diameter data are incomplete. In this study, we analytically evaluate the effects of changing the radial conductance between t...

Following exposure of portions of mature maize (Zea mays L.) leaf strips to (14)CO(2), xylem exudate from the leaf strips contained [(14)C]sucrose. Sucrose was the only sugar in the xylem exudate which was obtained from the cut surface of the leaf strips by reducing the external pressure. The sucrose found in the xylem exudate apparently was obtained from the free space of the vascular bundles,...

A huge number of deaths in the world are the direct or indirect consequence of a disease which is called atherosclerosis. The disease could be due to an artery blockage by the interaction of an externally second phase with a particle which is entered to the bloodstream. The effect of some most important physical and geometrical affecting parameters on the blockage time of a microchannel due to ...

The evolution of lignified xylem allowed for the efficient transport of water under tension, but also exposed the vascular network to the risk of gas emboli and the spread of gas between xylem conduits, thus impeding sap transport to the leaves. A well-known hypothesis proposes that the safety of xylem (its ability to resist embolism formation and spread) should trade off against xylem efficien...

Boreal hardwood species, including Japanese white birch (Betula platyphylla Sukat. var. japonica Hara), Japanese chestnut (Castanea crenata Sieb. et Zucc.), katsura tree (Cercidiphyllum japonicum Sieb. et Zucc.), Siebold's beech (Fagus crenata Blume), mulberry (Morus bombycis Koidz.), and Japanese rowan (Sorbus commixta Hedl.), had xylem parenchyma cells (XPCs) that adapt to subfreezing tempera...

The distribution of (14)C from xylem-borne [(14)C]glutamine, the major nitrogen compound moving in xylem sap of cottonwood (Populus deltoides Bartr. ex Marsh), was followed in rapidly growing shoots with a combination of autoradiographic, microautoradiographic, and radioassay techniques. Autoradiography and (14)C analyses of tissues showed that xylem-borne glutamine did not move with the transp...

Five new mathematical triple fouling models were developed to explore the flux decline behavior during the microfiltration. The first model was developed by the assumption of the successive effects of standard mechanism, intermediate pore blockage and cake formation by using the standard blocking flux expression in the model calculations. The second and third models also obtained by the success...

The secondary xylem of woody plants transports water mechanically supports the plant body and stores resources. These three functions are interdependent giving rise to tradeoffs in function. Understanding the relationships among these functions and their structural basis forms the context in which to interpret xylem evolution. The tradeoff between xylem transport efficiency and safety from cavi...