Xylem-dwelling pathogens become systemic, suggesting that microorganisms move efficiently in the xylem. To better understand xylem pathways and how bacteria move within the xylem, vessel connectivity between stems and leaves of Vitis vinifera cv. Chardonnay and Muscadinia rotundifolia cv. Cowart was studied. Three methods were used: (1) the light-producing bacterium, Yersinia enterocolitica, (Y...

In higher plants the pH of the xylem sap plays an important role in drought signaling, growth regulation, and plant nutrition. However, the interpretation of the data is very controversial. The main reason for this is that the xylem pH in intact plants was not directly accessible hitherto. We present here a novel, minimally-invasive probe based on the xylem pressure-potential probe (used for me...

In a series of experiments with Ricinus communis, abscisic acid (ABA) concentrations in tissues and transport saps, its de novo biosynthesis, long-distance transport, and metabolism (degradation) were affected by nutritional conditions, nitrogen (N) source, and nutrient limitation, or salt stress. In the present study these data were statistically re-evaluated, and new correlations presented th...

Tracheids, vessels and sieve tubes are found in the vascular tissue of the plant. • Tracheids and vessels are found in the xylem tissue and conduct water and dissolved mineral ions from the roots to the aerial parts of the plant. • Sieve tubes are found in the phloem tissue and conduct organic solutes, for example, sugars and amino acids, up and down the plant, from where they are synthesised t...

The progress of xylem formation in Norway spruce (Picea abies (L.) Karst.) was measured during one growing season in southern Finland. Stem radius was monitored continuously with band dendrometers, and the formation of new tracheids was determined by examination of small increment cores taken twice weekly. Tracheid production started in June and ceased in August. Xylem formation was fastest in ...

Direct determinations and indirect calculations of phloem turgor pressure were compared in white ash (Fraxinus americana L.). Direct measurements of trunk phloem turgor were made using a modified Hammel-type phloem needle connected to a pressure transducer. Turgor at the site of the direct measurements was calculated from the osmotic potential of the phloem sap and from the water potential of t...

Secondary growth of the vasculature results in the thickening of plant structures and continuously produces xylem tissue, the major biological carbon sink. Little is known about the developmental control of this quantitative trait, which displays two distinct phases in Arabidopsis thaliana hypocotyls. The later phase of accelerated xylem expansion resembles the secondary growth of trees and is ...

Xylem resistance to drought-induced cavitation is a key trait of plant water relations. This study assesses the genetic variation expressed for stem cavitation resistance within a population of a riparian species, the European black poplar (Populus nigra L.), and explores its relationships with xylem anatomy, water-use efficiency (WUE), and growth. Sixteen structural and physiological traits re...

To obtain the physical parameters and contact of ramie stalk decorticating simulation, structural dimensions, density, moisture content, elastic modulus, were measured in this study based on phloem xylem stalk. The stacking angles by cylinder lift method extraction partition method, respectively. between directly calibrated. Additionally, phloem–phloem, phloem–Q235A steel, xylem–xylem, xylem–Q2...

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...