Changes during development in the permeability of sclerotia ofSclerotinia minor to an apoplastic tracer

PROTOPLASMA ◽  
1992 ◽  
Vol 167 (3-4) ◽  
pp. 205-214 ◽  
Author(s):  
Nicola Young ◽  
Anne E. Ashford
Keyword(s):  
Apoplastic Tracer

Water Pathways in Wheat Leaves. IV. The Interpretation of Images of a Fluorescent Apoplastic Tracer

1988 ◽  
Vol 15 (4) ◽  
pp. 541 ◽  
Author(s):  
MJ Canny
Keyword(s):  
Cell Walls ◽  
Water Movement ◽  
Freeze Substitution ◽  
Sheath Cell ◽  
High Concentration ◽  
Mestome Sheath ◽  
Wheat Leaves ◽  
Apoplastic Tracer ◽  
Very High ◽  
Wall Components

Sections of wheat leaves fed with the fluorescent apoplastic tracer sulforhodamine G (SR) through the xylem were prepared by freeze-substitution and resin embedding. The distribution of fluorescence intensity (FI) of the tracer was measured by microspectrofluorometry at a resolution of 0.4 �m. SR was found to move within cell walls in restricted paths less than 200 nm wide. The name 'nanopaths' is suggested for these. The highest FI was found around the mestome-sheath / parenchyma-sheath border on the xylem side, and was shown to be due, not to binding of the tracer to wall components, but to the generation of a very high concentration of SR there by the separation of water from the solute. This separation cannot be evaporative but must be osmotic, and is presented as evidence of a major symplastic water movement starting at the parenchyma sheath cell membrane. The main resistance to water loss from the veins is at the mestome sheath and appears to be controlled by the suberised lamellae.

The use of lanthanum to characterize cell wall permeability in relation to the freezing response of woody plants

1987 ◽  
Vol 45 ◽  
pp. 988-989
Author(s):  
M. Wisniewski ◽  
K. Schaffer ◽  
W. Hershberger
Keyword(s):  
Cell Walls ◽  
Woody Plants ◽  
Water Movement ◽  
Freeze Tolerance ◽  
Freeze Avoidance ◽  
Deep Supercooling ◽  
Integral Role ◽  
Apoplastic Tracer ◽  
Cellular Water ◽  
Cell Wall Permeability

In woody plants, tissues displaying freeze tolerance respond to low temperature by the rapid loss of cellular water to extracellular ice whereas tissues exhibiting freeze avoidance exhibit deep supercooling in which case cellular water is isolated from the dehydrative and nucleating effects of extracellular ice. Biophysical data on cells that exhibit deep supercooling has led some authors to speculate that the structure and size of pores in cell walls would play an integral role in imparting a barrier to water movement and spread of ice. Distribution of the apoplastic tracer, lanthanum nitrate, was examined in stem tissues of several species of woody plants using a transmission electron microscope (TEM) in order to acquire data on general permeability of cell walls in species that deep supercool (P. persica, C. florida, B. lenta) vs. those that exhibit extracellular freezing (S. babylonica, B. papyrifera).

Beneficial effects of direct foliar water uptake on shoot water potential of five chasmophytes

2003 ◽  
Vol 81 (12) ◽  
pp. 1278-1284 ◽  
Author(s):  
E Gouvra ◽  
G Grammatikopoulos
Keyword(s):  
Water Absorption ◽  
Water Potential ◽  
Water Movement ◽  
Water Shortage ◽  
Leaf Water ◽  
Beneficial Effects ◽  
Time Period ◽  
Leaf Surfaces ◽  
Foliar Water Uptake ◽  
Apoplastic Tracer

Five chasmophytic species growing as wall-fissure plants on vertical retaining walls of a castle in the town of Patras, Greece, were examined for their ability to benefit from direct absorption of foliar surface water. Epifluore scence microscopy and application of an apoplastic tracer of water movement indicated that sprayed water on leaf surfaces penetrated into the mesophyll of all species, and in some cases was also detected within conducting tissues of the leaf. Water potential (Ψw) of sprayed detached shoots was improved compared with unsprayed controls when they were slowly losing water under laboratory conditions. The beneficial effect of leaf water absorption on Ψw was found either on leaves that were originally fully turgid or on leaves that had undergone a considerable water content reduction. Sprayed leaves maintained their Ψw above turgor loss point for a time period of 10-90 min depending on species and degree of water deficiency. The relevance of the results to the importance of dew uptake from chasmophytes growing under water shortage in wall fissures in inhabited areas is discussed.Key words: chasmophytes, leaf water absorption, wall vegetation, drought resistance.

scholarly journals Xylem sap analysis reveals new facts of salt tolerance in rice genotypes

2007 ◽  
Vol 19 (3) ◽  
pp. 185-192 ◽  
Author(s):  
Parto Roshandel
Keyword(s):  
Salt Tolerance ◽  
Xylem Sap ◽  
Salt Resistance ◽  
Salt Transport ◽  
Apparent Difference ◽  
Bypass Flow ◽  
The Third ◽  
The Difference ◽  
Apoplastic Pathway ◽  
Apoplastic Tracer

Salinity damage in rice and other salt-sensitive species is due to excessive transport of NaCl through the root system to the leaves and consequently low salt transport to the shoot can be a major trait determining salt resistance. Since the rapid uptake of sodium ions is such a crucial part of the response of rice to salinity, physiological experiments were carried out to compare bypass flow in two genotypes of rice (IR4630 and IR15324) differing in salt tolerance, because it has been suggested that an apoplastic pathway, bypass flow, is a major contributory pathway for Na+ entrance into rice plants. Experiments on the youngest fully expanded photosynthetic leaf (the third from the base), using PTS as a tracer for apoplastic movement and Philaenus spumarius (a xylem-feeding insect) as a means to sample the xylem sap, did not demonstrate any apparent difference in bypass flow between the two lines. The similarity of Na+ concentration in the xylem sap of both genotypes paralleled the results of PTS (a fluorescent dye used as an apoplastic tracer for the transpiration stream) measurements. Despite the similarity of Na+ concentration in the xylem sap of the third leaves, the Na+ concentration in the bulk of these leaves of IR15324 plants (the sensitive line) was about twice that of IR4630 (the tolerant line). Measurements of transpiration over 8 d of salinisation showed the similarity of rates in both lines providing evidence that the greater accumulation of NaCl in IR15324 than in IR4630 plants was unlikely to be due to a difference in the delivery of salt to the leaves by an apoplastic route. Results of the current work suggest that the difference in salt tolerance might be a consequence of damage to leaves 1 and 2 of IR15324 that allowed Na+ to leak into the phloem - and consequently move to leaf 3.

scholarly journals Some Accessions of Amazonian Wild Rice (Oryza glumaepatula) Constitutively Form a Barrier to Radial Oxygen Loss along Adventitious Roots under Aerated Conditions

Plants ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 880
Author(s):  
Masato Ejiri ◽  
Yuto Sawazaki ◽  
Katsuhiro Shiono
Keyword(s):  
Wild Rice ◽  
Periodic Acid ◽  
Genetic Regulation ◽  
Wetland Plants ◽  
Radial Oxygen Loss ◽  
Root Tips ◽  
Cultivated Rice ◽  
Oxygen Loss ◽  
Wild Rice Species ◽  
Apoplastic Tracer

A barrier to radial oxygen loss (ROL), which reduces the loss of oxygen transported via the aerenchyma to the root tips, enables the roots of wetland plants to grow into anoxic/hypoxic waterlogged soil. However, little is known about its genetic regulation. Quantitative trait loci (QTLs) mapping can help to understand the factors that regulate barrier formation. Rice (Oryza sativa) inducibly forms an ROL barrier under stagnant conditions, while a few wetland plants constitutively form one under aerated conditions. Here, we evaluated the formation of a constitutive ROL barrier in a total of four accessions from two wild rice species. Three of the accessions were wetland accessions of O. glumaepatula, and the fourth was a non-wetland species of O. rufipogon. These species have an AA type genome, which allows them to be crossed with cultivated rice. The three O. glumaepatula accessions (W2165, W2149, and W1183) formed an ROL barrier under aerated conditions. The O. rufipogon accession (W1962) did not form a constitutive ROL barrier, but it formed an inducible ROL barrier under stagnant conditions. The three O. glumaepatula accessions should be useful for QTL mapping to understand how a constitutive ROL barrier forms. The constitutive barrier of W2165 was closely associated with suberization and resistance to penetration by an apoplastic tracer (periodic acid) at the exodermis but did not include lignin at the sclerenchyma.

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.

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