ALBERT

Notes: 14C-glyphosate (N-(phosphonomethyl)glycine) uptake by germinating maize (Zea mays L. ‘PAG SX56’) or soybean (Glycine max (L.) Merr. ‘Williams’) seeds from sterile quartz sand was minimal on a weight basis until the radicle became functional. Uptake in soybean seedlings was ten times greater (on a weight basis) than in maize. Germination of either species was not affected by glyphosate concentrations up to 10−3m, but seedling axis elongation was inhibited in soybeans at 10−4m and in maize at [0−3m When 14C-glyphosate was applied to the fully expanded first trifoliolate soybean leaf (assimilate-exporting), movement into root and shoot assimilate sinks occurred. About 7% of the total 14C-glyphosate applied was absorbed and translocated into other parts of the plant by 48 h. Of the total 14C accumulated by 48 h in the roots and apical meristem, nearly 50% was present by 12 h. Minor phytotoxicity resulted from 10 nmoles of glyphosate in the plant. Absorption et migration du 14 C-glyphosate chez le maïs (Zea mays) en germination et chez les semences et les plantes de soja (Glycine max)L'absorption du 14C-glyphosate (N-(phosphonométhyle) glycine)par du maïs en germination (Zea mays L.,‘PAG SX56′)ou par des semences de soja (Glycine max (L.) Merr.,‘Williams’) a partir de sable de quartz stérile a été minimale (sur la base du poids) jusquà ce que la racine devienne fonctionnelle. L'absorption par des plantules de soja a été, sur la base due poids, 10 fois plus grande que chez le maïs. La germination de ces deux espèn n'a pas été affectée par des concentrations de glyphosate allant jusquà 10−3m, maïs l'élongation des plantules a été inhibée chez le soja á 10−4m et chez le maïs à 10−3m. Lorsque le 14C-glyphosate a été appliqué sur la première feuille trifoliée de soja pleinement dévdoppé (en état d'exporter des métabolites).une diminution du mouvemem des métabolites vers les jeunes pousses et vers les racines s'est manifestée. Eaviron 7% du 14C-glyphosate total appliqué a été absorbé et a migré dans d'autres parties de la plume en 48 heures. Près de 50% du 14C total accumulé dans les racines et le méristème apical y était présent en 12 heures. Une faible toxicité a réulté de b présence de 10 nmoles de glyphosate dans la plante. 14 C-glyphosat-Aufnahme und -Translokation bei keimenden Samen von Mais (Zea mays) und Sojabohnen (Glycine max) und bei SojabohnenpflanzenDie Aufnahme von 14C-Glyphosat (N-(Phosphonomethyl)glycin) aus sterilem Quarszsand durch keimende Samen von Mais (Zea mays L.‘PAG SX56′) und Sojabohnen (glycine max (L.) Merr.‘Williams’) war, bezogen auf das Pflanzengewicht, bis zur Funktionsaufnahme der Keimwurzel, gering. Die Aufnahme war bei den Sojabohnenkeimlingen zehnmal grösser (Gewichts-basis) als bei Mais. Die Keimung wurde bei beiden Arten durch Glyphosat bis zu 10−3m nicht beeinflusst. Das Streckungswachstum des Stengels wurde aber bei der Sojabohne bei 10−4m und beim Mais bei 10−3m gehemmt. Wenn 14C-Glyphosat auf das erste vollstándig entwickelte dreibláttrige Sojabohnenblatt (Assimilate exportierend) appliziert wurde, konnte ein Transport in die Assimilatesinks der Wurzel und des Sprosses beobachtet werden. Nach 48 h waren etwa 7% des applizierten 14C-Glyphosats aufgenommen und in andere Teile der Pflanze transloziert. Vom gesamten nach 48 h in den Wurzeln und im apikalen Meristem akkumulierten 14C waren fast 50% bereits nach 12 h vorhanden. 10 nmol Glyphosat in den Pflanzen waren nur geringfügig phytntoxisch.

Notes: The formation and subsequent conversions of 14C-labelled compounds were followed in fruits of Malus domestica cvs. Golden Delicious and Cox's Orange Pippin after labelling proximate leaves with 14CO2 at different times during the growing season. A few hours after labelling of the leaves, the larger share of fruit 14C was detected in sorbitol. This share descreased rapidly except in the late autumn. When labelling about 1 July (c. 1 month after bloom), 40–60% of the fruit 14C was permanently fixed in the methanol and water insoluble fraction. 25% or more was primarily found in organic acids, but this declined during the season to a few per cent. When labelling at the end of July, the dominating feature was the establishment of a peak of temporarily insoluble 14C, returning back to the soluble form through October and November. This was particularly pronounced in‘Cox's Organe Pippin'. Labelling with 14C at the end of August and at the end of September yielded increasing amounts of 14C in sugars. The labelling of fructose predominated, but as the autumn progressed the amount of label in sucrose increased. This was due to a conversion from 14C-compounds of older origin as well as to a larger share of the imported assimilates turning into sucrose at this time of the year. During prolonged storage of harvested fruits at 3°C, 14C in fructose increased at the expense of 14C in sucrose.

Notes: The Compartmentation of 14CO2 fixation and concomitant metabolism of l4C-iabelled products in a recombined system, composed of isolated intact spinach (Spinacia oleracea) chloroplasls and a ‘cytoplasm’ fraction, has been studied. Addition of ‘cytoplasm’ to chloroplasts fixing 14CO2 increased the label in hexoae monophosphates outside the chloroplasts at the expense of excreted dihydroxyacetone phosphate. The label in ammo acids was increased both inside and outside the chloroplasts. The results support the view that chloroplasls are not able to make 2-oxoacids for amino acid synthesis directly from fixed CO2, but have to co-operate with the cytoplasm and other organelles. The results also show that recombined systems can be useful for studies on the compartmen tation of carbon metabolism in pholosynthesizing plant tissues.