When an excised corn (Zea mays) root pretreated with chloride was exposed for 10 minutes to pulse labeling with (30)Cl and then transferred to unlabeled chloride, the activity in the xylem exudate reached a maximum about 4 minutes after pulse labeling was discontinued and then declined sharply. The rate at which labeled chloride was transported across the root into the xylem and basipetally the...

Quantitative and qualitative lignin analyses were carried out on material from the trunks of silver birch (Betula pendula Roth) trees. Two types of material were analyzed. First, whole birch trunk pieces were cryosectioned into cork cambium, non-conductive phloem, the cambial zone (conductive phloem, cambium and differentiating xylem), lignified xylem and the previous year's xylem; material tha...

In field-grown soybeans (Glycine max L. Merr. cv Harosoy), the percentage of N in the xylem as ureides increased with increasing N(2) fixation. During a 9-week collection period, the ureide content varied from 9.0 to 69.2% of the xylary N. Between 9 and 11 weeks (early pod fill), there was a good correlation (r = 0.93) between C(2)H(2) reduction and the per cent N in xylem as ureides. The per c...

Pressure transducers were attached to twigs of orchard trees and potted trees of walnut (Juglans regia L.) to measure winter stem xylem pressures. Experimental potted trees were partially defoliated in the late summer and early autumn to lower the amount of stored carbohydrates. Potted trees were placed in cooling chambers and subjected to various temperature regimes, including freeze-thaw cycl...

To identify mechanisms for the simultaneous release of anions and cations into the xylem sap in roots, we investigated voltagedependent ion conductances in the plasmalemma of xylem parenchyma cells. We applied the patch-clamp technique to protoplasts isolated from the xylem parenchyma by differential enzymic digestion of steles of barley roots (Hordeum vulgare 1. cv Apex). In the whole-cell con...


 Arbuscular mycorrhizal fungi (FMA) is a potential microbial that can increase plant growth in various conditions of planting media, including post-mining soil limestone. In the land, limestone has been found several types FMA. This type FMA as an inoculant source thought to red jabon (anthocephalus macropyllus). Furthermore PT. Holcim Indonesia Tbk also produces remaining cement launderi...

Nitrogen availability has a strong influence on plant growth and development. In this study, we examined the effect of nitrogen availability on xylogenesis in hybrid poplar (Populus trichocarpa x deltoides H11-11). Saplings of hybrid poplar were fertilized for 33 d with either high or adequate levels of ammonium nitrate. We observed enhanced radial growth, wider vessels and fibres and thinner f...

When conifers such as Chinese white pine (Pinus armandi Fr.) are attacked by insects or pathogens, they respond by increasing their content of monoterpenes and sesquiterpenes. In this study, we determined the effects of the blue-stain fungus Leptographium qinlingensis Tang and Chen on monoterpenes and sesquiterpenes in the phloem and xylem of the stem of P. armandi saplings. We found that the t...

The time scale of stomatal closure and xylem cavitation during plant dehydration, as well as the fate of embolized organs, are under debate, largely due to methodological limitations in the evaluation of embolism. While some argue that complete stomatal closure precedes the occurrence of embolism, others believe that the two are contemporaneous processes that are accompanied by daily xylem refi...

Many phytopathogenic bacteria, such as Ralstonia solanacearum, Pantoea stewartii, and Xanthomonas campestris, produce exopolysaccharides (EPSs) that aid in virulence, colonization, and survival. EPS can also contribute to host xylem vessel blockage. The genome of Xylella fastidiosa, the causal agent of Pierce's disease (PD) of grapevine, contains an operon that is strikingly similar to the X. c...