Apoplasmic Transport in Tissues

Läuchli, André

doi:10.1007/978-3-642-66230-0_1

Cited by 33 publications

(16 citation statements)

References 83 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…One is the differences found between endodermal cells and adjacent cortical cells. This has particular relevance to the role of the symplast and development of the endodermis (10,18). The other is the difference between cells of the epidermis and underlying cortex.…”

Section: Resultsmentioning

confidence: 99%

“…Plants were used when about 7 days old. The solutions used were: (a), 0.5 mm CaSO4; (b), full nutrient solution containing (in mm concentration) 2.5 K, 7.5 Na, 10 Cl, 3 Mg, 2 Ca, 3 S04,4 NO3, and 0.8 phosphate (pH 5.5); (c), 0.5 mM KCI + 4.5 mM NaCl + 0.5 mM CaSO4; and (d), 0.5 mM CaSO4, transferred to 5 mm NaCl + 0.5 mm CaSO4 24 h before measurements.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Ion Distribution in Roots of Barley Seedlings Measured by Electron Probe X-Ray Microanalysis

Pitman

Läuchli²,

Stelzer³

1981

Plant Physiol.

View full text Add to dashboard Cite

The distribution of ions, particularly K and Na, was studied in roots of barley seedlings grown on various ionic solutions. Analyses were made by means of electron probe x-ray microanalysis using frozen, fractured bulk specimens. By this technique, it was demonstrated that there can be variability in the ratio K/Na measured in the vacuoles of cortical cells, with this ratio often being lower in epidermal cells of the root than in the inner cortex. A sharp difference in the K/Na ratio was also found between cells of the endodermis and those of the adjacent cortex, and generally higher ratios of K/Na occurred in the stele than in the cortex. Estimation of the concentrations in the cytoplasm was at the limit of resolution of this technique, but It can be shown that the K/Na ratio in the cytoplasm was higher than that in the vacuole. In low salt roots, the K concentration in the cytoplasm was higher than that in the vacuoles. The results with the xray microprobe confirm other measurements based on flux analysis or analysis of small samples of the root.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Ion Distribution in Roots of Barley Seedlings Measured by Electron Probe X-Ray Microanalysis

Pitman

Läuchli²,

Stelzer³

1981

Plant Physiol.

View full text Add to dashboard Cite

show abstract

“…It would likely occur as diffusion down a concentration gradient, established at one end of the system by phloem unloading and maintained at the other end by active photosynthate accumulation or utilization by the embryo. Although an apoplastic route undoubtedly restricts the total capacity of a transport system (9), the environmental sensitivity of the processes at either end of this system (Thorne, unpublished) Passage through the Embryo Sac. The morphology, ultrastructure, and function of the embryo sac in soybean seeds nearing maturity have not been previously described.…”

Section: Probable Pathway Of Photosynthate Importmentioning

confidence: 99%

Morphology and Ultrastructure of Maternal Seed Tissues of Soybean in Relation to the Import of Photosynthate

Thorne

1981

Plant Physiol.

106

View full text Add to dashboard Cite

Cytological observations were made on developing seeds of soybean (Glycine max (L.) Meff. "Amsoy 71") using scanning and transmission electron microscopy and light microscopy. Attention was focused on the matermal tissues of the seed coat and embryo sac. An hypothesis of photosynthate import, unloading, and movement to the embryo is presented based on the results of these studies.The agronomic productivity of soybean plants is dependent upon their capacity to partition a significant proportion of assimilates to the seeds. Indeed, the principal sink for phloem-translocated photosynthate in reproductive soybeans is the seed (20), and large amounts are imported to provide the energy requirements of seed growth and establishment of cotyledonary reserves. Recent kinetic and biochemical studies have presented an overview of photosynthate import within soybean fruit (22, 23). These identify the transport role of the seed coat and suggest that specialized transport processes may control the uptake of sucrose by developing soybean seeds (23). They trace the route of photosynthate transport (23), but provide no cellular or ultrastructural information for the evaluation of physiological controls. Although some aspects of the vascularization of developing legume fruit have been described in other studies (2-4, 7, 10, 17), a comprehensive investigation is lacking, especially with respect to the overall import of photosynthate. The present study was undertaken primarily to describe the anatomical structure of the maternal tissues of the soybean seed coat and embryo sac in an attempt to determine the probable pathway (s) Scanning Electron Microscopy. Freshly harvested seeds were submerged, dissected, and then fixed at 4 C for 1.5 h in 5% (v/v) glutaraldehyde containing 100 mm phosphate buffer (pH 7.0). After two 15-min rinses in phosphate buffer, tissue samples were postfixed for 1.5 h in 1% (v/v) osmium tetroxide containing 100 mM cacodylate buffer (pH 7.0). Following slow dehydration through a graded ethanol series, samples in absolute ethanol were dried using the critical point method of Anderson (1), vacuumdesiccated at room temperature, fractured, attached to specimen studs, and coated with gold-palladium prior to viewing with an ETEC "Autoscan" scanning electron microscope operated at 10 kv.Transmission Electron Microscopy. All tissue preparation was conducted at 4 C unless otherwise indicated. Segments of seed coat one mm2 were dissected from freshly harvested seeds while submerged in 5% (v/v) glutaraldehyde containing 100 mm phosphate buffer (pH 7.0). Segments were held under vacuum in the fixative for 24 h. Following vacuum infiltration, tissue samples were rinsed for 15-min three times in the same buffer and then postfixed 1 h with 1% (v/v) osmium tetroxide in Palade's buffer (16). The fixed tissue was dehydrated through 15-min steps of 50, 70, 95 (3x), and finally 100%o ethanol (3x), followed by two 15-min changes of propylene oxide. The samples were held overnight at room temperature in a 1:1 mixture (v/v)...

show abstract

“…It can be assumed from these results that the Mn which was bound with cell wall constituents incIuding pectic substances, glycoproteins and lectins and cuticle may have been removed by this strong extractant. LAÜCHLI (10), in his review on cell wall chemistry, mentioned that the carboxyl groups of a-D-polygalacturonic acid and lectins preferentially bind divalent cations. It has also been reported that cuticle binds much higher amounts of cations than anions, just like a cation exchanger (5,10).…”

Section: Resul Ts and Discussionmentioning

confidence: 99%

“…LAÜCHLI (10), in his review on cell wall chemistry, mentioned that the carboxyl groups of a-D-polygalacturonic acid and lectins preferentially bind divalent cations. It has also been reported that cuticle binds much higher amounts of cations than anions, just like a cation exchanger (5,10). It is suggested from these results that Mn bound with cuticle may have been exchanged for H+ cations of hydrochIoric acid.…”

Section: Resul Ts and Discussionmentioning

confidence: 99%