STUDIES ON PHLOEM EXUDATION FROM<i>YUCCA FLACCIDA HAW</i>.

Tammes, P. M. L.; Die, J. Van

doi:10.1111/j.1438-8677.1964.tb00140.x

Cited by 73 publications

(11 citation statements)

References 20 publications

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“…D-Galacturonic acid, which is also a component of the plant cell wall, was more effective in stimulating vir gene induction than D-galactose (unpublished data). Although it is not clear whether exudates from wound sites in plants contain a sufficient amount of the effective sugars to enhance vir gene expression, glucose has been reported to be present at a concentration of 10 mM in wound exudates from some plants (32,33). Because the active sugars are effective even at concentrations lower than 1 mM (Fig.…”

Section: Discussionmentioning

confidence: 99%

Control of expression of Agrobacterium vir genes by synergistic actions of phenolic signal molecules and monosaccharides.

Shimoda

Toyoda-Yamamoto²,

Nagamine³

et al. 1990

Proc. Natl. Acad. Sci. U.S.A.

169

117

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but does not enhance the expression of noninducible genes. Likewise, a 2-deoxy-D-glucose, a nonmetabolized sugar, is also effective. When a deletion was introduced into the virA gene in the region encoding the periplasmic portion of the VirA protein, enhancement by glucose disappeared, but vir expression was induced by acetosyringone in this mutant. These results suggest that these sugars directly enhance a signaling process initiated by phenolic inducers that results in an-increase in expression of the vir genes.

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Section: Discussionmentioning

confidence: 99%

Control of expression of Agrobacterium vir genes by synergistic actions of phenolic signal molecules and monosaccharides.

Shimoda

Toyoda-Yamamoto²,

Nagamine³

et al. 1990

Proc. Natl. Acad. Sci. U.S.A.

169

117

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“…Some plants exude if their sieve tubes are opened (e.g. Ricinus communis: Kallarackal et al 1989;Hall et al 1971; Yuccaflaccida: Tammes and van Die 1964). But the volume flow rate so-observed cannot be considered as providing a reliable measure of the actual in-vivo flow occurring in the intact plant since (i) any opening of the sieve tubes changes the total resistance of the flow pathway and (ii) the opening will create an infinite strong sink for phloem solutes.…”

Section: Introductionmentioning

confidence: 97%

A non-invasive measurement of phloem and xylem water flow in castor bean seedlings by nuclear magnetic resonance microimaging

Köckenberger

Pope

Xia

et al. 1997

Planta

154

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Abstract. A flow-sensitive nuclear magnetic resonance (NMR) microimaging technique was applied to measure directly the in-vivo water flow in 6-d-old castor bean seedlings. The achieved in-plane resolution of the technique allowed discrimination between xylem and phloem water flow. Both the xylem-and the phloem-average flow velocities in the intact seedling could be quantified. Furthermore, the total conductive cross-sectional area of the xylem vessels and the phloem sieve elements could be determined using the non-invasive and non-destructive NMR microimaging technique. Hence, it was possible to calculate the in-vivo volume flow rates for both xylem and phloem water flow. Our non-destructive technique showed that previously used methods to measure phloem water flow affected the flow rate itself. In the intact seedlings we found values of 16.6 pl-h-1, two fold lower than those previously estimated from phloem exudation rates. Finally, our results demonstrate for the first time that water is internally circulated between phloem and xylem, and that water flow within the xylem is maintained by this internally circulated water, even in the absence of any significant transpiration or evaporation.

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“…In some cases one can isolate the sap simply by cutting the plant stem and collecting the fluid that exudes from the incision. This method is suitable for a few plants, such as yucca [52], castor bean [53][54][55] and squash [56] that produce relatively large volumes of phloem sap. But for most plants, the phloem flow clogs very easily, and sufficient volumes of fluid cannot be collected by this method.…”

Section: Introductionmentioning

confidence: 99%