A rapid fluorescence technique to probe the permeability of the root apoplast

1992 ◽  
Vol 70 (7) ◽  
pp. 1493-1501 ◽  
Author(s):  
Daryl E. Enstone ◽  
Carol A. Peterson
Keyword(s):  
Plant Tissue ◽  
Broad Bean ◽  
Potassium Thiocyanate ◽  
Toxicity Tests ◽  
Fluorescence Technique ◽  
Tracheary Elements ◽  
Bright Yellow ◽  
Primary Roots ◽  
Casparian Band ◽  
Apoplastic Tracer

The alkaloid berberine is useful as a mobile apoplastic tracer. It is readily precipitated by thiocyanate, forming bright yellow, needle-like, fluorescent crystals. When berberine hemisulphate and potassium thiocyanate are applied sequentially to plant tissue, the crystals form in unmodified walls and in the lumina of dead cells such as tracheary elements. Lignified and suberized walls stain with berberine but do not develop crystals. Regions of the plant that have been penetrated by the chemicals can be located by preparing freehand sections, mounting them in potassium thiocyanate to inhibit dissolution of the crystals, and examining them with a fluorescence microscope. When the two chemicals are sequentially introduced into the xylem of onion, corn, and broad bean roots, the tracer does not pass the endodermal Casparian band, indicating that the system traces apoplastic pathways. The chemical concentrations that produce sufficient crystals so that berberine can be used as an apoplastic tracer in primary roots are 0.05% berberine hemisulphate and 0.09 M potasium thiocyanate. These concentrations were not toxic to cells of onion bulb epidermis. They reduced the growth rates of corn and broad bean roots but did not kill them. Berberine–thiocyanate is a useful apoplastic tracer provided care is taken not to exceed the limits of berberine toxicity to the tissue. Key words: apoplastic tracer, berberine hemisulphate, potassium thiocyanate, roots, toxicity tests, corn, onion, broad bean.

Development of endodermal Casparian bands and xylem in lateral roots of broad bean

1990 ◽  
Vol 68 (12) ◽  
pp. 2729-2735 ◽  
Author(s):  
Carol A. Peterson ◽  
Barbara E. M. Lefcourt
Keyword(s):  
Broad Bean ◽  
Lateral Roots ◽  
Staining Procedure ◽  
Tracheary Elements ◽  
Main Root ◽  
Fluorochrome Staining ◽  
Primary Xylem ◽  
Casparian Bands ◽  
Casparian Band

A clearing and fluorochrome staining procedure for broad bean (Vicia faba L. cv. Windsor) roots with laterals was devised which allowed observation of their tracheary elements and Casparian bands in situ. The Casparian band of the main root overlying the primordium disappeared early in its development and the margins of the remaining band were displaced outward during subsequent growth of the lateral. The Casparian band matured centripetally in parenchyma across the base of the lateral as far as the endodermis of the lateral and then acropetally into the lateral itself. Casparian bands of the laterals were always connected to those of the main roots. In actively growing roots, the primordium may have emerged as far as 2.7 mm from the main root and still contain no differentiating xylem or Casparian band. Longer laterals contained differentiating xylem 3 mm from the tip and maturing Casparian bands 5 mm from the tip. In nongrowing roots, some primordia not yet emerged from the main root had mature xylem tracheary elements 0.4 mm from the tip and mature Casparian bands 0.25 mm from the tip. Key words: Casparian band, primary xylem, lateral roots, endodermis.

Pathway of movement of apoplastic fluorescent dye tracers through the endodermis at the site of secondary root formation in corn (Zea mays) and broad bean (Vicia faba)

1981 ◽  
Vol 59 (5) ◽  
pp. 618-625 ◽  
Author(s):  
Carol A. Peterson ◽  
Mary E. Emanuel ◽  
G. B. Humphreys
Keyword(s):  
Zea Mays ◽  
Root Formation ◽  
Broad Bean ◽  
Primary Root ◽  
Root Primordia ◽  
Secondary Root ◽  
Point Of Entry ◽  
Primary Roots ◽  
Apoplastic Pathway ◽  
Root Treatment

The apoplastic dyes disodium 4,4′-bis (2-sulfostyryl) biphenyl (Tinopal CBS), a fabric brightener which is bound by cellulose, and trisodium, 3-hydroxy-5,8,10-pyrene trisulfonate (PTS), which is not bound by the walls, were used to trace an apoplastic pathway into the vascular tissues of corn and broad bean roots. The endodermis prevented dye entry into the stele in most regions of roots. However, if the roots were killed prior to dye treatment both dyes entered the steles, indicating that in healthy roots the dyes were confined to the apoplast and were not toxic in the applied concentrations. The more mobile dye, PTS, appeared in the shoots of the plants following a root treatment, indicating that an apoplastic pathway into the stele does exist in the roots. Neither dye penetrated into the steles at the tips of the primary roots. The point of entry in both corn and broad bean was located along the margin of a secondary root which had recently emerged from the epidermis of the primary root. The dyes did not enter the steles of the primary roots during earlier stages of secondary root development, nor did they enter through the secondary root primordia themselves.

The Action of the Systemic Insecticide Systox, on Aphids

1954 ◽  
Vol 45 (4) ◽  
pp. 683-692 ◽  
Author(s):  
W. A. L. David ◽  
B. O. C. Gardiner
Keyword(s):  
Active Ingredient ◽  
Myzus Persicae ◽  
Plant Tissue ◽  
Broad Bean ◽  
Aphis Fabae ◽  
Systemic Insecticide ◽  
Toxic Compound ◽  
Toxic Material ◽  
Tap Root ◽  
Image Position

The work described in this paper has been carried out with two proprietary samples, designated Systox 50 emulsion and E 1059, of a systemic insecticide of which the active ingredient, subsequently referred to throughout as Systox, is a mixture of O,O-diethyl O-ethylmercaptoethyl thiophosphate and its isomer, O,O-diethyl S-ethylmercaptoethyl thiophosphate.The samples were tested against Aphids for contact and systemic action.It is concluded that, as a contact insecticide against Aphis fabae Scop, on broad beans, Systox is about equitoxic with paraoxon and so more toxic than schradan and dimefox.Systox is readily absorbed by the roots of broad bean and cabbage plants from soil, sand and aqueous solutions and the translocated material is very effective as an insecticide against A. fabae on broad bean, and Myzus persicae (Sulz.) and Brevicoryne brassicae (L.) on cabbage.Applied in this way, Systox is more effective than schradan, dimefox and paraoxon, and about equal to the most toxic compound previously tested, sodium fluoroacetate.An experiment by the cut tap-root technique confirms these conclusions. A dose of 1 mg. of Systox per kg. of fresh bean-plant tissue gave a complete kill of A. fabae by the 10th day. The same amount of sodium fluoroacetate had previously been shown to give a complete kill in three days.The plants were carefully watched for signs of damage during the tests. It was concluded that there was a considerable margin between the insecticidally effective and the phytotoxic concentrations.Systox is also translocated from older to younger leaves of bean and cabbage plants and it may reach concentrations sufficient to kill the Aphids feeding on the untreated leaves. This effect was more consistently obtained in the broad bean than in cabbage plants. In both cases, however, the results were variable.Solutions of Systox exert a direct fumigant action on Aphids, but there is little evidence that toxic material is transpired by treated plants.

Effect of secondary growth on the conformation and permeability of the endodermis of broad bean (Vicia faba), sunflower (Helianthus annuus), and garden balsam (Impatiens balsamina)

1984 ◽  
Vol 62 (5) ◽  
pp. 907-910 ◽  
Author(s):  
Carol Ann Weerdenburg ◽  
Carol A. Peterson
Keyword(s):  
Cross Sections ◽  
Broad Bean ◽  
Uv Light ◽  
Secondary Growth ◽  
Root Extract ◽  
Chelidonium Majus ◽  
Calcofluor White ◽  
Casparian Band ◽  
Apoplastic Barrier ◽  
Endodermal Cells

A root undergoing secondary growth exhibits massive girth increases owing to the activity of the vascular cambium. To determine the effects of this growth on endodermal structure and function, cleared cross sections from areas of primary and secondary growth in broad bean, sunflower, and garden balsam roots were examined. Casparian bands were detected by staining the sections with Chelidonium majus root extract and viewing them with ultraviolet (uv) light using an epifluorescence microscope. Endodermal diameter and numbers of endodermal cells increased dramatically in the area of secondary growth. The distance spanned by the Casparian band (i.e., the tangential width of the endodermal cells) between radial walls also increased except in sunflower. The permeability of the endodermis to an apoplastic fluorescent dye in roots undergoing secondary growth was tested by treatment with Calcofluor white M2R. In all species examined, the Casparian band continued to function as an effective apoplastic barrier during early stages of secondary growth despite the increase in endodermal cell size and number. Eventual decortication with concurrent disruption of the endodermis resulted in massive penetration of Calcofluor white M2R into the xylem.

Freeze-fracture, freeze-etch complementary pairs of virus-infected cells reveal value of etching even when relatively high concentrations of cryoprotectants are used

1978 ◽  
Vol 36 (2) ◽  
pp. 136-137
Author(s):  
Russell L. Steere ◽  
Eric F. Erbe
Keyword(s):  
Plant Tissue ◽  
Phosphate Buffer ◽  
Infected Plant ◽  
Freeze Fracture ◽  
Distilled Water ◽  
Virus Infected Plant ◽  
Infected Cells ◽  
High Concentrations

It has been assumed by many involved in freeze-etch or freeze-fracture studies that it would be useless to etch specimens which were cryoprotected by more than 15% glycerol. We presumed that the amount of cryoprotective material exposed at the surface would serve as a contaminating layer and prevent the visualization of fine details. Recent unexpected freeze-etch results indicated that it would be useful to compare complementary replicas in which one-half of the frozen-fractured specimen would be shadowed and replicated immediately after fracturing whereas the complement would be etched at -98°C for 1 to 10 minutes before being shadowed and replicated.Standard complementary replica holders (Steere, 1973) with hinges removed were used for this study. Specimens consisting of unfixed virus-infected plant tissue infiltrated with 0.05 M phosphate buffer or distilled water were used without cryoprotectant. Some were permitted to settle through gradients to the desired concentrations of different cryoprotectants.

Anatomy and ultrastructure of haustoria in selected West Australian parasitic angiosperms

1990 ◽  
Vol 48 (3) ◽  
pp. 690-691
Author(s):  
John Kuo ◽  
John S. Pate
Keyword(s):  
Parasitic Plants ◽  
The Other ◽  
Nutrient Transfer ◽  
Direct Solution ◽  
Tracheary Elements ◽  
Solute Transfer ◽  
Glycol Methacrylate ◽  
Australian Species ◽  
Anatomy And Ultrastructure ◽  
Solution Transfer

Our understanding of nutrient transfer between host and flowering parasitic plants is usually based mainly on physiological concepts, with little information on haustorial structure related to function. The aim of this paper is to study the haustorial interface and possible pathways of water and solute transfer between a number of host and parasites.Haustorial tissues were fixed in glutaraldehyde and embedded in glycol methacrylate (LM), or fixed in glutaraldehyde then OsO4 and embedded in Spurr’s resin (TEM).Our study shows that lumen to lumen continuity occurs between tracheary elements of a host and four S.W. Australian species of aerial mistletoes (Fig. 1), and some root hemiparasites (Exocarpos spp. and Anthobolus foveolatus) (Fig. 2). On the other hand, haustorial interfaces of the root hemiparasites Olax phyllanthi and Santalum (2 species) are comprised mainly of parenchyma, as opposed to terminating tracheads or vessels, implying that direct solution transfer between partners via vessels or tracheary elements may be limited (Fig. 3).

Structural aspects of tracheary element differentiation in suspension cultures of Zinnia elegans

1989 ◽  
Vol 47 ◽  
pp. 768-769
Author(s):  
C. H. Haigler ◽  
A. W. Roberts
Keyword(s):  
Tracheary Element ◽  
Vesicle Fusion ◽  
Zinnia Elegans ◽  
Cellulose Synthesis ◽  
Tracheary Elements ◽  
Animal Cells ◽  
Mesophyll Cells ◽  
Fixation Techniques ◽  
Localized Patterns ◽  
Structural Aspects

Tracheary elements, the water-conducting cells in plants, are characterized by their reinforced walls that became thickened in localized patterns during differentiation (Fig. 1). The synthesis of this localized wall involves abundant secretion of Golgi vesicles that export preformed matrix polysaccharides and putative proteins involved in cellulose synthesis. Since the cells are not growing, some kind of endocytotic process must also occur. Many researchers have commented on where exocytosis occurs in relation to the thickenings (for example, see), but they based their interpretations on chemical fixation techniques that are not likely to provide reliable information about rapid processes such as vesicle fusion. We have used rapid freezing to more accurately assess patterns of vesicle fusion in tracheary elements. We have also determined the localization of calcium, which is known to regulate vesicle fusion in plant and animal cells.Mesophyll cells were obtained from immature first leaves of Zinnia elegans var. Envy (Park Seed Co., Greenwood, S.C.) and cultured as described previously with the following exceptions: (a) concentration of benzylaminopurine in the culture medium was reduced to 0.2 mg/l and myoinositol was eliminated; and (b) 1.75ml cultures were incubated in 22 x 90mm shell vials with 112rpm rotary shaking. Cells that were actively involved in differentiation were harvested and frozen in solidifying Freon as described previously. Fractures occurred preferentially at the cell/planchet interface, which allowed us to find some excellently-preserved cells in the replicas. Other differentiating cells were incubated for 20-30 min in 10(μM CTC (Sigma), an antibiotic that fluoresces in the presence of membrane-sequestered calcium. They were observed in an Olympus BH-2 microscope equipped for epi-fluorescence (violet filter package and additional Zeiss KP560 barrier filter to block chlorophyll autofluorescence).

Freeze-Fracture Studies of Membranes in Developing Sieve Elements in a Plant Tissue Culture

1980 ◽  
Vol 38 ◽  
pp. 636-637
Author(s):  
R. D. Sjolund ◽  
C. Y. Shih
Keyword(s):  
Plant Tissue ◽  
Cultured Cells ◽  
Freeze Fracture ◽  
Tissue Cultures ◽  
Sieve Elements ◽  
Intact Plants ◽  
Plant Tissue Cultures ◽  
Whole Plants ◽  
Energy Dependent ◽  
Similar Elements

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.

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