Results 141 to 150 of about 1,784,085 (182)

CALLOSE SUBSTANCE IN SIEVE ELEMENTS

American Journal of Botany, 1964
The secondary phloem of 6 species of woody dicotyledons was examined for the occurrence of callose on the sieve plates of active sieve elements. Fluorescence and bright‐field staining methods were used to detect callose. Tissue from the 6 species was killed and fixed in each of 5 solutions. Some tissue of each species was submerged
Ray F. Evert, William F. Derr
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Removing the nucleus in sieve elements

Science, 2014
Cellular remodeling to develop phloem cells orchestrates degradation of the cell’s nucleus.
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Sieve–element characters

Nordic Journal of Botany, 1981
Of all the ultrastructural features recognized within sieve elements their specific plastids provide the most successful characters in seed plant systematics. Sieve–element plastids are classified into subtypes and forms according to their protein and starch contents. Presently 26 different forms grouped into six subtypes within the two basic types (S–
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Strands in Sections of Sieve Elements Cut in a Cryostat

Nature New Biology, 1971
Observations of these strands are consistent with the idea of trans-cellular strands of cytoplasm in sieve tubes.
P, Jarvis, R, Thaine
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Sieve element pores in Nicotiana pith culture

Journal of Ultrastructure Research, 1970
Sieve elements were induced to form in cultured pith cylinders of Nicotiana tabacum L. (var. Wisconsin 38). Both xylem and phloem differentiate in isolated nodules at the periphery of the cylinders. The mature sieve elements closely resemble sieve elements in intact plants but are more irregular in shape and usually not highly elongated.
R, Anderson, J, Cronshaw
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The development of the sieve elements of Pinus pinea

Planta, 1966
The fine structure found in the developing and mature secondary phloem of Pinus pinea is described. No longitudinal system of conduits in the sieve elements has been found at any stage in their differentiation. The endoplasmic reticulum undergoes a characteristic series of changes and possible functions are considered.
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Aspects of sieve element ultrastructure in Primula obconica

Planta, 1966
At maturity, the enucleate sieve element of Primula obconica is lined with a parietal layer of cytoplasm consisting of plasmalemma, one or more cisterna-like layers of endoplasmic reticulum, numerous mitochondria and plastids, and a membrane which apparently separates these cytoplasmic components from a large central cavity. The central cavity contains
S R, Tamulevich, R F, Evert
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Microtubules in differentiating sieve elements of Gossypium hirsutum

Journal of Ultrastructure Research, 1982
Changes in distribution, orientation, and abundance of microtubules (MT) in relation to sieve element differentiation in root protophloem and stem and midvein metaphloem of Gossypium hirsutum were studied at the ultrastructural level. Depending on their stage of differentiation the sieve elements were divided into four previously characterized groups ...
J, Thorsch, K, Esau
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Sieve Elements of Graft Unions

1990
In grafted plants the various relations between scion and stock are based on exchange of heterogeneous substances between the partners; many of them being organic compounds which are translocated in the symplast (see reviews by Brabec 1965 and Carr 1976).
Rainer Kollmann, Christl Glockmann
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Wound-Sieve Elements

1990
The survival of higher plants is highly dependent upon the phloem path linking assimilate sources and sinks. In an individual plant the elongation, capacity and function of this path have to be finely adjusted to internal and environmental conditions.
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