15 torthaí
Simultaneous monitoring of ATP synthesis and K+ movements across pea mitochondrial membranes revealed information about the competition of the two processes for mitochondrial energy. In the presence of valinomycin and at low extramitochondrial K+ concentration, ADP could be phosphorylated rapidly.
Germination of nondormant but impotent small cocklebur seeds (Xanthium pennsylvanicum Wallr.) was promoted profoundly with thiourea or benzyladenine, and slightly with gibberellic acid. Gibberellic acid was ineffective in causing the germination of dormant cocklebur seeds, although thiourea and
Methodology was developed for measurement of K+ transport in pea cotyledon mitochondria isolated by zonal centrifugation. The valinomycin-mediated transport process required respiratory energy from Krebs cycle intermediates and was completely reversible in the absence of oxygen. The rate and extent
1. The 25 000-30 000 X g fraction from sugar beet leaf or roots contains, together with (Na+ plus K+)-activated ATPase, also K+-stimulated inorganic pyrophosphatase. 2. This inorganic pyrophosphatase is also stimulated by Rb+ and to a lesser degree by Li+ and Na+. 3. Na+ is at the same time an
An acute outbreak of C. orbiculata L. poisoning in a flock of 16 Angora Goat rams is described. Typical signs of acute bufadienolide cardiac glycoside toxicity were manifested and 6 animals died. In the 2 animals examined histopathologically multiple foci of myocardial degeneration and necrosis were
The perfused human placental cotyledon was examined with respect to its viability, metabolic state, and performance. During the ischemic period before the start of perfusion, tissue adenosine triphosphate concentration and other measures of energy state fell rapidly to about half of the estimated in
The interactions between carbon and nitrogen metabolism in cotyledons of germinating Ricinus communis L. seedlings were investigated. The endosperm was removed for 6-d-old seedlings and their cotyledons were supplied with 50 mM glucose and mM potassium phosphate without a nitrogen source, or
Energy dispersive x-ray analysis was used to study the composition of certain protein body components in Cucurbita maxima cotyledons. The globoid crystal was rich in phosphorus, potassium, and magnesium. This elemental composition provides further evidence that the globoid crystal in squash
In Ricinus cotyledons, evidence for proton extrusion came from observation of direct acidification of the medium in the presence of potassium salts. Increasing K(+) influx with increasing pH suggested a link between K(+) influx and H(+) efflux by an H(+) pump. The kinetics of K(+) influx and H(+)
Dormant seeds of cocklebur (Xanthium pennsylvanicum Wallr.) were characterized by the lack of ability to form chlorophyll. Such an inability of cotyledons of the dormant seeds was improved by the application of various factors and reagents which were capable of breaking the dormancy and of
Decapitation of the shoot apex of seedlings of Helianthus annuus Lin. above the cotyledonary node brought about promotion of growth in the cotyledons. Potassium level in the cotyledons of decapitated plants was higher, and that of sodium lower, than in those of intact plants. IAA applied to the cut
A method is described for the sub-cellular ractionation of cotyledons from non-germinated Phaseolus vulgaris seeds in non-aqueous density gradients of potassium iodide in glycerol. The major organelles (protein bodies, cell walls and starch grains) are well resolved as adjudged by morphology and
Exudate was collected fromRicinus communis L. cotyledons after cutting the hypocotyl. It contained high levels of sucrose and potassium, a low level of calcium, and a pH of approx. 7.5. After application of [(14)C] sucrose to the cotyledons, radioactivity could be recovered from the exudate,
The effects of calcium on chlorophyll accumulation and its stability in the early phase of greening in cucumber cotyledons were investigated. Chlorophyll accumulation was hardly affected by dark preincubation of cotyledons with 10 millimolar calcium solution, but was inhibited almost completely when
The elemental composition of globoids in the protein bodies of Protea compacta cotyledons was studied by means of energy dispersive X-ray analysis. The globoid crystal was rich in phosphorus and calcium with lesser amounts of magnesium and potassium suggesting the presence of phytin in these