منابع مشابه
Phloem loading in squash.
Squash (Cucurbita pepo L. var. melopepo torticalis, Bailey) leaves were supplied with (14)C-sucrose, then specific radioactivities of the glucose and galactose moieties of translocated stachyose were determined. In every case, the specific radioactivity of the galactose moiety was greater than that of the glucose moiety. It is concluded that the stachyose was not synthesized at either the phloe...
متن کاملEffect of petiole anoxia on Phloem transport in squash.
Translocation of (14)C-labeled assimilates in Early Prolific Straightneck squash (Cucurbita melopepo torticollis Bailey) through a 15-centimeter oxygen-deficient zone of the petiole was studied as a function of varying periods of anaerobiosis (N(2) atmosphere). Initiation of anaerobic conditions caused an immediate and rapid decline in translocation to about 35 to 45% of the pretreatment rate w...
متن کاملSymplastic Phloem Loading in Poplar1[W][OPEN]
Sap is driven through phloem sieve tubes by an osmotically generated pressure gradient between source and sink tissues. In many plants, source pressure results from thermodynamically active loading in which energy is used to transfer sucrose (Suc) from mesophyll cells to the phloem of leaf minor veins against a concentration gradient. However, in some species, almost all trees, correlative evid...
متن کاملThe role of phloem loading reconsidered.
It is generally assumed that the primary role of phloem loading is to drive long-distance transport by elevating hydrostatic pressure in sieve elements. This concept is consistent with the fact that, in many plants, energy is used to increase the concentrations of photoassimilates in the leaf phloem to levels well above those in mesophyll cells. However, on the basis of recent data, these funda...
متن کاملPhloem Loading through Plasmodesmata: A Biophysical Analysis.
In many species, Suc en route out of the leaf migrates from photosynthetically active mesophyll cells into the phloem down its concentration gradient via plasmodesmata, i.e. symplastically. In some of these plants, the process is entirely passive, but in others phloem Suc is actively converted into larger sugars, raffinose and stachyose, and segregated (trapped), thus raising total phloem sugar...
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ژورنال
عنوان ژورنال: Plant Physiology
سال: 1977
ISSN: 0032-0889,1532-2548
DOI: 10.1104/pp.60.4.567