PROTOPLAST STRUCTURE IN SIEVE TUBE ELEMENTS
نویسندگان
چکیده
منابع مشابه
Structure of functional soybean sieve elements.
Soybean (Glycine max cv. Bragg) petiolar tissue containing translocated (14)C-sucrose was quick frozen, freeze-substituted in acetone or propylene oxide and embedded in Epon. This procedure allowed cytological observations on sieve elements whose functional condition could be verified by microautoradiography. Sieve elements and companion cells were essentially free of ice damage. Aside from a P...
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Because sieve elements are generally regarded as the specialized conducting cells in the phloem tissue, their structure in relation to function has been the subject of many studies and discussions. ' Both the protoplast and the walls of sieve elements have distinctive characteristics, some of which are difficult to relate to the rapid flow of materials-at the rate of up to 100 cm. per hour-reco...
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A procedure is described for the measurement of the sieve tube membrane potential in the phloem of bark strips from Salix exigua Nutt. Measurements were made by inserting a measuring microelectrode into sap exuding from severed stylets of the willow aphid, Tuberolachnus salignus. Data taken from 20 bark strips gave an average potential of -155 +/- 9 millivolts. Evidence is presented for an elec...
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Although the enucleate conducting cells of the phloem are incapable of protein synthesis, phloem exudates characteristically contain low concentrations of soluble proteins. The role of these proteins and their movement into and out of the sieve tubes poses important questions for phloem physiology and for cell-to-cell protein movement via plasmodesmata. The occurrence of protein turnover in sie...
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Sieve elements are one of the least understood cell types in plants. Translocation velocities and volume flow to supply sinks with photoassimilates greatly depend on the geometry of the microfluidic sieve tube system and especially on the anatomy of sieve plates and sieve plate pores. Several models for phloem translocation have been developed, but appropriate data on the geometry of pores, pla...
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ژورنال
عنوان ژورنال: New Phytologist
سال: 1964
ISSN: 0028-646X,1469-8137
DOI: 10.1111/j.1469-8137.1964.tb07376.x