Exogenous Substrate Utilization and Fermentation by the Pollen of Pinus ponderosa.

SEQUESTRATION OF CYTOPLASMIC ORTHOPHOSPHATE BY MANNOSE AND ITS DIFFERENTIAL EFFECT ON PHOTOSYNTHETIC STARCH SYNTHESIS IN C3 AND C4 SPECIES

“…These include growth and metabolism of excised roots (Knudson, 1917;Stenlid, 1954, i957> i959a>b;Morgan and Street, 1959;Butcher and Street, 1964;Goldworthy and Street, 1965), respiration of maize scutella (Garrard and Humphreys, 1969), ion uptake by roots and subsequent transport to shoots (Loughman, 1966), germination of seeds and pollen (Daoud and Tadros, 1935;Hellmers and Machlis, 1956), algal growth and metabolism (Gross, 1968) and the synthesis of starch in leaf discs (Chen-She, Lewis and Walker, 1975).…”

Mannose and Green Plants: Occurrence, Physiology and Metabolism, and Use as a Tool to Study the Role of Orthophosphate

“…Deoxyglucose inhibits both phosphorylase and UDP-glucosyltransferase from Prototheca (Rana and Casselton, 1974). The effect of mannose on these enzymes does not appear to have been tested but it may be significant that degradation of starch and paramylum in vivo is inhibited in its presence (Hellmers and Machlis, 1956;Blum and Wittels, 1968;Herold, unpublished-see Table 5 above. See also Section V below regarding the effect of [Pi] on chloroplast metabolism).…”

“…Initial experiments (Herold, unpublished) have indicated a reduced rate of starch breakdown in spinach in the presence of 10 mM mannose. Further evidence for the role of Pi (which could, of course, be a direct stimulation of phosphorylase activity) in mobilization of glucan is given by Hellmers and Machlis (1956) who noted a complete inhibition of starch degradation in pollen of ponderosa pine in the presence of mannose (<55 mM) and by Blum and Wittels (1968) who recorded that mannose inhibited degradation of paramylum in Euglena.…”

Utilization of Exogenous Sugars for Biosynthesis of Carbohydrates in Germinating Pollen

“…Further evidence for the utilization of exogenous carbohydrate was presented by other workers (1,7,13), who demonstrated synthesis of starch by pollen germinated in various sugar solutions. A more detailed study of the in vitro utilization of exogenous carbohydrate by germinating pollen is presented in this paper, showing that the carbohydrate is transformed to other complex saccharides in addition to starch.…”