Bicarbonate assimilation by fresh-water charophytes and higher plants: I. Membrane transport of bicarbonate ions is not proven

1980 ◽  
Vol 57 (1) ◽  
pp. 51-58 ◽  
Author(s):  
N. A. Walker ◽  
F. A. Smith ◽  
I. R. Cathers
Keyword(s):  
Membrane Transport ◽  
Fresh Water ◽  
Higher Plants ◽  
Bicarbonate Ions

scholarly journals The Mechanism of Sodium and Chloride Uptake by the Gills of a Fresh-Water Fish, Carassius auratus

1964 ◽  
Vol 47 (6) ◽  
pp. 1209-1227 ◽  
Author(s):  
J. Maetz ◽  
F. García Romeu
Keyword(s):  
Fresh Water ◽  
Carassius Auratus ◽  
Opposite Effect ◽  
External Medium ◽  
Sodium Balance ◽  
Fresh Water Fish ◽  
Sodium Influx ◽  
Chloride Uptake ◽  
Bicarbonate Ions ◽  
Net Uptake

The addition of ammonium ions to the external medium results in an inhibition of the sodium influx and net uptake in Carassius auratus, while intraperitoneal injection of ammonium produces the opposite effect. The simultaneous chloride balance is not significantly affected by these treatments. The addition of bicarbonate ions to the external medium results in a reduction of the influx and net flux of chloride, while injection of bicarbonate produces the opposite effect. The simultaneous sodium balance is not significantly altered. The effects of the external additions are reversible after elimination of the excess ammonium or bicarbonate ions by rinsing. Inhibition of carbonic anhydrase in the gill by injection of acetazoleamide produces a simultaneous inhibition of both sodium and chloride exchanges. These results confirm the hypothesis of an exchange of sodium for ammonium, and of bicarbonate for chloride across the gill. A tentative schematic representation of the ionic absorption mechanisms in the branchial cell of the fresh-water teleosts is given. Similarities with other biological membranes and especially with the renal tubule are pointed out.

Salinity tolerance in Spergularia marina

1985 ◽  
Vol 63 (10) ◽  
pp. 1762-1768 ◽  
Author(s):  
John M. Cheeseman ◽  
P. Bloebaum ◽  
Carol Enkoji ◽  
Linda K. Wickens
Keyword(s):  
Fresh Water ◽  
Higher Plants ◽  
Specific Effect ◽  
Distribution Patterns ◽  
Growth Stimulation ◽  
Solution Culture ◽  
Ion Content ◽  
Physiological Basis ◽  
Leaf Surface Area ◽  
Spergularia Marina

Attributes of the coastal halophyte Spergularia marina (L.) Griseb. that make it useful for studies of the physiological basis for salt tolerance in fully autotrophic higher plants are discussed. Growth, morphological, and ion-content characteristics are presented to serve as a background for subsequent studies of transport physiology. Plants were grown in solution culture on dilutions of artificial seawater or on the same solution without NaCl ("fresh water") from the time at which they could be conveniently transferred as seedlings (about 2 weeks old) to the onset of flowering about 5 weeks later. Eighteen days after transfer, plants growing on 0.2 × seawater were larger, being nearly twice the size of plants on fresh water. A Na+ specific effect was indicated, as the major part of the growth stimulation (54%) resulted from a 1 mM NaCl supplementation of "fresh water." Succulence was not a consideration in the growth response: root length was directly proportional to weight as was leaf surface area and neither was affected by salinity. Total Na+ plus K+ per gram root or shoot showed little variation with salinity from 1 to 180 mM Na+ levels. In roots, the relative Na+ and K+ contents were also little affected by salinity, but in the shoots, increasing salinity resulted in higher Na+ and lower K+ contents. Distribution within the shoots of 0.2 × plants showed no regions either free of or exceptionally high in Na+. The ion content and distribution patterns are compared with those in a number of other halophytes.

V.—The Connection of the Glacial Period with Oscillation of the Land, especially in Scandinavia

1901 ◽  
Vol 8 (5) ◽  
pp. 205-216 ◽  
Author(s):  
Nils Olof Holst ◽  
F. A. Bather
Keyword(s):  
Baltic Sea ◽  
Fresh Water ◽  
Higher Plants ◽  
Geological Survey ◽  
Glacial Period ◽  
The Baltic Sea ◽  
Gulf Of Bothnia ◽  
The Baltic ◽  
Published Paper

[In a recently published paper Dr. N. O. Holst, of the Geological Survey of Sweden, has given a detailed description of the Post-Glacial deposits of the Baltic Sea and the Gulf of Bothnia. The paper is accompanied by a map showing the chief points of observation. The determination of the different horizons depends on (1) the stratigraphy; (2) the sub-fossil diatomaceous flora; (3) the sub-fossil higher flora. The stratigraphical evidence is in the form of numerous sections, taken all along the coast. The diatoms are used chiefly, but not solely, to distinguish the marine from the fresh-water deposits; their determinations, nearly 3,000 in number, are due to Professor P. T. Cleve and his daughter, Dr. Astrid Cleve. The remains of the higher plants have been determined by Dr. Gunnar Andersson.

Role of membrane transport in phloem translocation of assimilates and water

2001 ◽  
Vol 28 (7) ◽  
pp. 697 ◽  
Author(s):  
John W. Patrick ◽  
Wenhao Zhang ◽  
Stephen D. Tyerman ◽  
Christina E. Offler ◽  
N. Alan Walker
Keyword(s):  
Membrane Transport ◽  
Reverse Genetics ◽  
Water Movement ◽  
Higher Plants ◽  
Amino Nitrogen ◽  
Phloem Loading ◽  
Transport Pathway ◽  
Phloem Translocation ◽  
Loading And Unloading ◽  
Phloem Loading And Unloading

Most growth and storage organs (sinks) of higher plants import assimilates in solution by bulk flow through the phloem, driven by differences in hydrostatic pressure. These differences in pressure, located between the ends of the interconnecting phloem path, are generated by osmotic water movement, driven in turn by membrane transport of solutes. Sucrose, amino-nitrogen compounds and potassium represent the osmotically important solutes found in phloem contents of most species. Phloem loading and unloading events of these assimilate species play central roles in determining phloem translocation rates and partitioning of assimilates and water. Depending on plant species, leaf vein order and sink type, phloem loading and unloading may follow apoplasmic or symplasmic routes. Irrespective of the cellular pathway followed, assimilates are transported across plasma and organellar membranes. Aquaporins, amino-nitrogen transporters, sucrose transporters and potassium channels have been detected in key sites along the source–phloem–sink transport pathway. Reverse genetics has demonstrated that sucrose/proton symporters are important in transport events necessary for phloem loading in Solanaceousplant species. Drawing on circumstantial evidence, we review possible functions the remaining membrane transporters and channels may serve in driving phloem translocation of assimilates and water from source to sink.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

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