Modification of the external pH by maize coleoptiles and velamen radicum of Vanilla planifoliaAndr.

Böttger, Michael; Soll, Hans-Jürgen; Gasché, Andrea

doi:10.1016/s0044-328x(80)80117-6

Cited by 16 publications

(4 citation statements)

References 11 publications

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“…Another special adaptation of epiphytic orchids is the velamen radicum, a modification of non‐living rhizodermis with a very high cell‐wall buffering capacity compared to that of maize coleoptiles ( Böttger 1980). The presence of this large volume of dead, water‐absorbing tissue, which has a high density of ion‐exchange sites, may help orchids to take up and retain nitrogen from rain that is flowing quickly over the roots.…”

Section: Discussionmentioning

confidence: 99%

Stable isotopic composition of carbon and nitrogen and nitrogen content in vascular epiphytes along an altitudinal transect*

Hietz

Wanek

Popp

1999

Plant Cell & Environment

107

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The foliar content of nitrogen and the relative abundances of 13C and 15N were analysed in vascular epiphytes collected from six sites along an altitudinal gradient from tropical dry forests to humid montane forests in eastern Mexico. The proportion of epiphyte species showing crassulacean acid metabolism (CAM) (atmospheric bromeliads, thick‐leaved orchids, Cactaceae, and Crassulaceae) decreased with increasing elevation and precipitation from 58 to 6%. Atmospheric bromeliads, almost all of which had δ13C values indicating CAM, were more depleted in 15N (x=−10·9‰± 2·11) than the C3 bromeliads which form water‐storing tanks (−6·05‰± 2·26). As there was no difference in δ15N values between C3 and CAM orchids, the difference in bromeliads was not related to photosynthetic pathways but to different nitrogen sources. While epiphytes with strong 15N depletion appear to obtain their nitrogen mainly from direct atmospheric deposition, others have access to nitrogen in intercepted water and from organic matter decomposing on branches and in their phytotelmata. Bromeliads and succulent orchids had a lower foliar nitrogen content than thin‐leaved orchids, ferns and Piperaceae. Ground‐rooted hemi‐epiphytes exhibited the highest nitrogen contents and δ15N values.

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Section: Discussionmentioning

confidence: 99%

Stable isotopic composition of carbon and nitrogen and nitrogen content in vascular epiphytes along an altitudinal transect*

Hietz

Wanek

Popp

1999

Plant Cell & Environment

107

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“…1A). The pH value of native cell walls could roughly be estimated to be around 6 (Vanderhoef et al 1977, Böttger et al 1980, Mizuno and Katou 1991. At pH 4.0, the wall fiber network easily broke even with low tension (Fig.…”

Section: Discussionmentioning

confidence: 98%

“…1A). It was difficult for the wall pH to be decreased from 6.0 to 4.0 by proton pumping because of the high buffering capacity of cell wall materials (Böttger et al 1980, Mizuno and Katou 1991, Peters and Felle 1991. Thus the observed narrow pH range between 6.0 and 5.0 seems to be suitable for the in vivo regulation of wall extension.…”

Section: Discussionmentioning

confidence: 99%

The Role of Wall Ca2+ in the Regulation of Wall Extensibility During the Acid-induced Extension of Soybean Hypocotyl Cell Walls

Ezaki¹,

Kido²,

Takahashi³

et al. 2005

Plant and Cell Physiology

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We examined the acid-facilitated yielding properties of cell walls of soybean hypocotyls and the effects of Ca(2+) upon the properties by stress-strain analyses using glycerinated hollow cylinders (GHCs) from the elongating regions of the hypocotyls. Stress-extension rate curves of native GHCs showed characteristic changes with pH, all indicating the existence of yield threshold tension (y) as well as wall extensibility (phi), i.e. a downward shift of y and an increase in phi with wall acidification. The acid-induced downward shift of y was inhibited by boiling of GHCs. In contrast, a considerable increase in phi with acidification remained even after boiling. This indicates that phi consists of two components, i.e. heat-sensitive and heat-resistant, both being pH sensitive. A Ca(2+) chelator (Quin 2) dramatically increased phi at a neutral pH. Subsequent addition of Ca(2+) or ruthenium red suppressed the chelator-induced increase in phi. These findings suggest that wall Ca(2+) plays an important role in the regulation of wall extensibility during the acid-induced wall extension by reacting with carboxyl groups of wall pectin.

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“…The cell wall apoplast has a high buffering capacity originating in the cation/proton exchange reaction on the wall polysaccharides (Bottger et al 1980, Grignon and Sentenac 1991, Mizuno and Katou 1991. Therefore, it may be difficult to observe the auxin-induced H*-excretion because the cell wall acts as a buffer by retaining excreted protons.…”

Section: Introductionmentioning

confidence: 99%

Effect of cations on IAA‐induced proton excretion in the xylem of Vigna unguiculata

Mizuno

Katou

1992

Physiologia Plantarum

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Perfusion of IAA through the xylem of a hypocotyl segment of Vigna unguiculata L. cv. Otsubu hyperpolarized the boundary membrane between the xylem and the symplast followed by acidification of the xylem exudate. K+, Ca2+ or Mg2+ enhanced IAA‐induced acidification of the xylem exudate. Cation‐induced acidification in IAA‐treated segment was observed even under anoxia. However, Na+ had only a small effect on the IAA‐induced acidification. Thus, the acidification enhanced by cations may not be due to the stimulation of a plasmalemma proton pump but originates in the cation/proton exchange on the cell wall. Apparently, IAA stimulates the electrogenic proton‐pump at the plasmalemma that excretes protons to the cell wall apoplast. The cell wall acts as a buffer, however, to hide the proton‐excretion unless the protons are exchanged with other cations. This may be the reason why IAA‐induced acidification of the bathing medium was not always observed when tested on several plant tissues.

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Modification of the external pH by maize coleoptiles and velamen radicum of Vanilla planifoliaAndr.

Cited by 16 publications

References 11 publications

Stable isotopic composition of carbon and nitrogen and nitrogen content in vascular epiphytes along an altitudinal transect*

Stable isotopic composition of carbon and nitrogen and nitrogen content in vascular epiphytes along an altitudinal transect*

The Role of Wall Ca2+ in the Regulation of Wall Extensibility During the Acid-induced Extension of Soybean Hypocotyl Cell Walls

Effect of cations on IAA‐induced proton excretion in the xylem of Vigna unguiculata

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