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 ...

The ability of juvenile Laurus nobilis and Acer negundo plants to refill embolized xylem vessels was tested under conditions of soil drought when xylem sap pressure was substantially negative, thus violating the expected condition that pressure must rise to near atmospheric for refilling. Intact potted plants were dried to a stem water potential ( Y W ) corresponding with approximately 80% loss...

Water stress effects on winter and spring leaves anatomy were investigated in experiments conducted at the experimental field of SB University of Kerman using five wheat cultivars.Xylem and phloem elements diameter and mesophyll, bundle sheath and epidermal cells area were measured in transverse sections prepared from middle parts of the leaves. Results showed that significant difference exists...

doi: 10.1111/j.1399-3054.2006.00680.x Pressure–volume (P–V) curves for leaves or terminal shoots summarize leaflevel responses to increasing water deficit. P–V curve traits and fieldmeasured shoot xylem pressures were characterized across 62 species from four sites differing in rainfall and soil phosphorus. Within-species variation in the measured traits was small relative to differences among ...

Warming and drought will occur with increased frequency and intensity at high latitudes in the future. How heat and water stress can influence tree mortality is incompletely understood. The aim of this study was to evaluate how carbon resources, stem hydraulics, and wood anatomy and density determine the ability of black spruce saplings to survive daytime or night-time warming (+ 6 °C in compar...

about the hydraulic properties of the plant vascular system. The traditional view of plant hydraulics being domSoil and xylem are similar hydraulically. An unsaturated conductivinated by resistances of endodermis and root cortex ity curve for soil is called a vulnerability curve for xylem—but the (Boyer, 1985; Philip, 1966) is expanding to include well underlying physical basis is the same. Thu...

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...

What is xylem required for? The xylem has evolved as a tissue to transport water and minerals from the roots to the tips of leaves using tubes of dead tracheary elements arranged end-toend. In addition, the xylem is required for supporting the plant body vertically on land. Thick secondary cell walls on xylem cells give the cells physical strength to help support the plant body and resist water...

Competition between ponderosa pine seedlings and various grasses and forbs was studied on :I site in northern Arizona burned in 1982 by a wildfire. Two-yearold pine seedlings were planted in 3.05 x 3.05 m plots in April 1983, followed by the sowing of grass and forb seeds on the same plots in July 1983 after summer rains had begun. Predawn xylem water potential of the pine seedlings was measure...

Laterally connected vascular bundles in the nodes of sugarcane (Saccharum species cv. Pindar) stalks allow a rapid redistribution of water across the stalk should the vascular continuity be partly disrupted. Tritiated water supplied to the roots exchanged rapidly between the xylem and storage tissue so that net movement up the stalk was slow. The half-time for exchange in a labeled stalk was ab...