Planta

Jones, Russell

doi: 10.1007/BF00387360pmid: 24481517

Aleurone cells of barley (Hordeum vulgare L.) contain microbodies as determined by histochemical localization with diaminobenzidine. These microbodies can be isolated from both water and gibberellic acid (GA3) treated cells and identified on sucrose density gradients as glyoxysomes on the basis of their buoyant densities (1.25 g cm-3) and their enzyme complement. Fractionation of aleurone layer homogenates by differential centrifugation after varying times of exposure to GA3, however, does not indicate the presence of a discrete secretory vesicle containing either α-amylase or β-1,3-glucanase. Cytological evidence also suggests that at least β-1,3-glucanase is not released from these cells by means of a discrete secretory vesicle.

Cheng, K.; Miller, A.; Colman, Brian

doi: 10.1007/BF00387361pmid: 24481518

The amount of 14C-glycolate excreted by Oscillatoria sp. and Anabaena flos-aquae is less than 1% of the 14C fixed by the algae during photosynthesis. Transfer of cells grown on 5% CO2 in air to a medium of low bicarbonate concentration or treatment of the cells with isonicotinyl hydrazide (INH) during photosynthesis, caused little increase in glycolate excretion. α-Hydroxysulfonates failed to stimulate massive excretion of glycolate. Although these blue-green algae excreted little glycolate, a significant proportion of the photosynthetically fixed carbon was excreted in the form of basic, neutral and acidic compounds, and such excretion was greater in 5% CO2-grown cells than in air-grown cells.

Fuchs, Yoram; Mayak, Shimon; Fuchs, Sara

doi: 10.1007/BF00387362pmid: 24481519

Antibodies with specificity towards abscisic acid (ABA) were produced in rabbits. These antibodies were used for assaying ABA by the inhibition of inactivation of modified bacteriophage. For this assay conjugates of ABA with bacteriophage T4 were prepared and characterized. Such chemically modified bacteriophages were completely inactivated by the specific anti-ABA serum and this inactivation was inhibited by free ABA. The identification and quantitative determination of ABA in plant extracts by this method are demonstrated and the method is compared with a common bioassay.

Blake, Jennet

doi: 10.1007/BF00387363pmid: 24481520

A bioassay for the inhibition of flowering involving the in vitro culture of excised, partially-induced, apices of Viscaria candida is described. This bioassay has been used to detect flowering inhibition in extracts from Kalanchoe blossfeldiana.

Brown, D.; Haslett, B.

doi: 10.1007/BF00387364pmid: 24481521

Changes in NADH- and NADPH-linked glutamic dehydrogenase (GDH) activity have been measured following illumination of etiolated barley leaves. Both activities initially increase, then decrease to below the etiolated value. The latter change is dependent upon prior illumination but independent of the presence of roots or added ammonium sulphate. Subsequently a sustained increase of both activities occurs. Possible reasons for these changes and alterations in the ratio of the two GDH activities are discussed.

Jones, M.; Mansfield, T.

doi: 10.1007/BF00387365pmid: 24481522

Detached shoots of Bryophyllum fedtschenkoi maintained in a closed system in the light exhibited an endogenous circadian rhythm in CO2 compensation. The rhythm was sensitive to changes in light intensity and temperature. At 15° C it damped rapidly in light of 78 J m-2 s-1, but at 10° C a rhythm of considerable amplitude was evident at this same light intensity. During the transient (i.e. the temporary state of the rhythm before it acquired its steady state) low compensation values between 0 and 5 ppm CO2 were achieved. When the plants were maintained at a higher light intensity prior to the measurements, the period of low compensation during the transient was extended, and zero values were obtained under some conditions.

Nordhorn, Gisela; Willenbrink, Johannes

doi: 10.1007/BF00387366pmid: 24481523

1. Of the buffer substances introduced by Good, only N-2-hydroxy-ethylpiperazine-N-2-ethanesulfonic acid (HEPES) and N-tris(hydroxymethyl)-methyl-2-aminoethanesulfonic acid (TES) were found suitable for the isolation of mitochondria by means of density gradient centrifugation in a silica sol. Addition of 1% polyvinylpyrrolidone remarkably reduced the respiration rate and diminished the respiratory control, whereas 2% dextran improved the rates. 2. Fifty mM malonate inhibited succinate oxidation by 55–72% compared with the controls; in addition an uncoupling effect was observed. Similar results were obtained with 2.5 mM amytal. 3. Antimycin A, in contrast, did not affect the respiratory control, while the respiration rate was depressed to 55% of that in the control. 4. Azide (20 mM) had only a slight effect on the two parameters of leaf mitochondria. 5. It can be concluded that mitochondria of leaf cells are provided with the same respiratory enzymes as those of other plant materials.

Ziegler, Irmgard

doi: 10.1007/BF00387367pmid: 24481524

SO 3 -- inhibits the activity of ribulose-1,5-diphosphate carboxylase in isolated spinach chloroplasts. It shows a non-competitive inhibition pattern with respect to ribulose-1,5-diphosphate and Mg++ but a competitive one with respect to HCO 3 - . The K i -values are 14 mM SO 3 -- and 9.5 mM SO 3 - respectively for the non-competitive inhibition but only 3.0 mM SO 3 -- in the case of competitive inhibition with HCO 3 -- as a substrate. Thus it is concluded that the competitive inhibition type will predominate at low SO 3 -- and low internal CO2 concentrations.

Jeschke, Wolf

doi: 10.1007/BF00387368pmid: 24481525

The light-dependent influxes of K+ and Cl- in detached leaves of Elodea densa were measured using 36Cl- and 42K+ or 86Rb+ as tracers.

Wild, Aloysius; Conrad, Gisela; Zickler, Hans-Otto

doi: 10.1007/BF00387369pmid: 24481526

The concentration of lipophilic plastid quinones (plastoquinone, plastoquinol, α-tocopherol, α-tocoquinone) in the C4-plants Zea mays and Atriplex rosea is lower than in the already studied C3-plants.