ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

Hits per page

hits 1 - 2 | 2 hits

Sorting

Electronic Resource

Distribution of plasma membrane rosettes and kinetics of cellulose formation in xylem development of higher plants (1986)

Schneider, B. ; Herth, W.

Springer

Protoplasma 131 (1986), S. 142-152

add to mindlist on the mindlist

Details

ISSN: 1615-6102

Keywords: Cellulose fibril formation ; Freeze-fracture ; Plasma membrane ; Rosette distribution ; Xylem development

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Summary Germ roots of several higher plants—maize (Zea mays), mung bean (Vigna radiata) and cress (Lepidium sativum)—were freeze-fractured without cryoprotection in order to confirm and extend the informations on frequency and distribution of plasma membrane particle complexes with respect to cellulose formation. In all three objects the PF of developing xylem elements showed rosette accumulations in the regions of wall thickenings. The rosette-distribution pattern ranges from random in a young stage, to more grouped in a probable intermediate stage to strictly localized in later stages. The frequency of rosettes increases from stage to stage. In all three objects the EF of developing xylem elements is relatively poor in particles. Observations of “terminal globules” were rare and undistinct. This leads to the assumption that rosettes on the PF and terminal globules on the EF are not part of the same complex. A comparison of the number and distribution of microtubules underlying the xylem wall thickenings with rosette frequency and distribution leads to the conclusion that there seem to be no direct connections between these two structures. Microtubules may be involved in grouping of rosettes, thus indirectly orienting microfibril deposition. Calculations based on the observed rosette frequencies and the amount of wall material formed indicate that in xylem development 1,000 nm elementary fibril per rosette per minute may be formed and that the active phase of one rosette may be about 10 minutes.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF01285036

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

Electronic Resource

Multiple-pulse 1H-NMR study of polystyrene gels (1985)

Geschke, D. ; Pöschel, K. ; Doskočilová, D. ; [et al.]

Weinheim : Wiley-Blackwell

Acta Polymerica 36 (1985), S. 645-648

add to mindlist on the mindlist

Details

ISSN: 0323-7648

Keywords: Chemistry ; Polymer and Materials Science

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology , Physics

Description / Table of Contents: Untersucht wurden 1H-FID- und MW4-Spektren vom mit Ethylendimethacrylat und Divinylbenzen vernetztem und mit CCl4, CDCl3 und Benzen gequollenem Polystyren. Die mit Hilfe von Vielimpulscyclen erreichbaren Linienverschmälerungen werden diskutiert und mit denen der MAR-Technik verglichen. Die Temperaturabhängigkeit der effektiven Relaxationszeit T2eff spiegelt die Dynamik lokaler Segmentprozesse wider.

Notes: 1H-FID and MW4-pulse spectra of polystyrene crosslinked with ethylene dimethacrylate or divinylbenzene and swollen in CCl4, CDCl3 or benzene, are measured. Line-narrowing effects of multiple-pulse sequences are discussed and compared with those of the MAR-technique. The temperature dependence of the effective relaxation time T2eff reflects the dynamics of local segmental processes.

Additional Material: 5 Ill.