scholarly journals 3-D Color Video Microscopy of Intact Plants: A New Method for Measuring Shape and Growth.

1998 ◽  
Vol 36 (4) ◽  
pp. 217-226 ◽  
Author(s):  
Kenji OMASA ◽  
Masaki KOUDA
2000 ◽  
Vol 11 (4) ◽  
pp. 1213-1224 ◽  
Author(s):  
Christoph Kaether ◽  
Paul Skehel ◽  
Carlos G. Dotti

Neurons transport newly synthesized membrane proteins along axons by microtubule-mediated fast axonal transport. Membrane proteins destined for different axonal subdomains are thought to be transported in different transport carriers. To analyze this differential transport in living neurons, we tagged the amyloid precursor protein (APP) and synaptophysin (p38) with green fluorescent protein (GFP) variants. The resulting fusion proteins, APP-yellow fluorescent protein (YFP), p38-enhanced GFP, and p38-enhanced cyan fluorescent protein, were expressed in hippocampal neurons, and the cells were imaged by video microscopy. APP-YFP was transported in elongated tubules that moved extremely fast (on average 4.5 μm/s) and over long distances. In contrast, p38-enhanced GFP-transporting structures were more vesicular and moved four times slower (0.9 μm/s) and over shorter distances only. Two-color video microscopy showed that the two proteins were sorted to different carriers that moved with different characteristics along axons of doubly transfected neurons. Antisense treatment using oligonucleotides against the kinesin heavy chain slowed down the long, continuous movement of APP-YFP tubules and increased frequency of directional changes. These results demonstrate for the first time directly the sorting and transport of two axonal membrane proteins into different carriers. Moreover, the extremely fast-moving tubules represent a previously unidentified type of axonal carrier.


2000 ◽  
Vol 27 (9) ◽  
pp. 835
Author(s):  
Ning Wang ◽  
Sze-Mei Cindy Lau ◽  
Gregory Rogers ◽  
Thomas Ray

This paper originates from a presentation at the International Conference on Assimilate Transport and Partitioning, Newcastle, NSW, August 1999 The deposition of hydrophobic polymers in the xylem of wheat grain floral axes prevents water and solute movement into grains via the xylem (xylem discontinuity). The only pathway for translocation of photosynthate or externally applied xenobiotics into wheat grains is via the phloem. We have developed a new method based on the xylem discontinuity for rapidly screening phloem mobility of xenobiotics. By quantifying xenobiotic concentration in grains and excised plants after the compounds were applied through the cut stems, the phloem mobility can be estimated quantitatively. The phloem mobility obtained with our new grain-based method was correlated to xenobiotic chemical properties such as log Kow, pKa and electrical charge, and is consistent with published literature. Phloem mobility values determined by the grain-based assay were correlated to those from the direct phloem sap (aphid stylet exudate) assay of excised and intact plants, indicating that the grain-based assay is as reliable as the direct assay with aphid stylectomy. The new grain-based method is simple, quick, and can be scaled up for rapid screening of xenobiotic phloem mobility in plants. Similar seed (fruit)-based assay could also be developed with wide ranges of plant species that use the phloem as the only pathway for supplying water and nutrients into their seeds or fruits.


1965 ◽  
Vol 18 (3) ◽  
pp. 487 ◽  
Author(s):  
ARG Lang ◽  
HD Barrs

A new method and apparatus for estimating water potentials in the xylem of intact plants are described. The apparatus is based on the thermocouple psychro-meter method of measuring water potentials, but measurements are made on leaves which remain attached to plants. Illustrative experiments are described, in which continuous records of the estimated water potential in the xylem of cotton and pepper plants are given for periods of up to 10 hr.


Author(s):  
C. C. Clawson ◽  
L. W. Anderson ◽  
R. A. Good

Investigations which require electron microscope examination of a few specific areas of non-homogeneous tissues make random sampling of small blocks an inefficient and unrewarding procedure. Therefore, several investigators have devised methods which allow obtaining sample blocks for electron microscopy from region of tissue previously identified by light microscopy of present here techniques which make possible: 1) sampling tissue for electron microscopy from selected areas previously identified by light microscopy of relatively large pieces of tissue; 2) dehydration and embedding large numbers of individually identified blocks while keeping each one separate; 3) a new method of maintaining specific orientation of blocks during embedding; 4) special light microscopic staining or fluorescent procedures and electron microscopy on immediately adjacent small areas of tissue.


Author(s):  
R. D. Sjolund ◽  
C. Y. Shih

The differentiation of phloem in plant tissue cultures offers a unique opportunity to study the development and structure of sieve elements in a manner that avoids the injury responses associated with the processing of similar elements in intact plants. Short segments of sieve elements formed in tissue cultures can be fixed intact while the longer strands occuring in whole plants must be cut into shorter lengths before processing. While iyuch controversy surrounds the question of phloem function in tissue cultures , sieve elements formed in these cultured cells are structurally similar to those of Intact plants. We are particullarly Interested In the structure of the plasma membrane and the peripheral ER in these cells because of their possible role in the energy-dependent active transport of sucrose into the sieve elements.


Nanoscale ◽  
2019 ◽  
Vol 11 (44) ◽  
pp. 21147-21154 ◽  
Author(s):  
Raymond W. Friddle ◽  
Konrad Thürmer

Video microscopy and AFM are used to relate surface topography to a mineral's ability to promote ice growth. On feldspar, abundant as atmospheric dust, basic surface steps can facilitate condensation and freezing when air becomes saturated.


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