Planta

Shone, M.; Clarkson, D.; Sanderson, J.

doi: 10.1007/BF00388956pmid: 24515855

The absorption and subsequent distribution of sodium and potassium has been examined in maize seedlings in short-term experiments using sodium-22 and potassium-42. The absorption and translocation of sodium by different segments of intact seedlings was also investigated. Although absorption of potassium exceeded that of sodium by a factor of about 50, there was no evidence that the entry of sodium was confined to a small region of the root. Determinations of the relative quantities of sodium and potassium in the xylem exudate of detached roots showed that the ratio of sodium to potassium decreased with increasing length of the root. These results suggested that upward movement of sodium in the xylem vessels was progressively reduced towards the basal part of the root. This conclusion was supported by microautoradiographs, which showed that although the concentration of sodium within the endodermis was greater than that in the cortex, there was an apparent decrease in the sodium content of the major xylem vessels at the basal end of the root.

Phillips, I.

doi: 10.1007/BF00388957pmid: 24515856

Seedlings of dwarf and tall varieties of pea and bean, growing in John Innes Compost No. 2, were studied in relation to the effects of decapitation, indole-3-acetic acid (IAA), and gibberellic acid (GA3) on axillary bud growth. In all varieties, GA3 antagonized the inhibitory influence of IAA on bud growth when both hormones were applied to the upper cut end of the stem. Thus, GA3 caused a reduction in IAA-induced correlative bud inhibition in tall, as well as in dwarf, plants. These results agree with those obtained by several workers, but contrast with some recent reports of increased apical dominance in a tall pea variety when seedlings were treated with GA3 in addition to IAA. An attempt was made to identify the cause of opposite results being obtained by different workers, and it is considered that possibly the most important factor is mineral nutrition.

Grotha, Rüdiger; Stange, Luise

doi: 10.1007/BF00388958pmid: 24515857

The synthesis of DNA in cells of tissue fragments from the wing of Riella is blocked specifically by treatment with 5-fluorodeoxyuridine. As a consequence of this blockage the nucleoli increase in size to about the 3-fold value of the control and show a higher intensity of staining specific for nucleic acids. Whereas in the control the increase in nucleolar size is restricted to a polar zone of the fragment, it spreads out over the fragment under the influence of FUDR.

Steiner, A.

doi: 10.1007/BF00388959pmid: 24515858

The dose response behaviour for polarotropism of the unicellular germ tube of Sphaerocarpos was studied in blue and near UV. At constant intensities the response is proportional to the logarithm of the exposure duration, and at constant exposure durations the response is proportional to the logarithm of intensity. Neither a polarotropic response to wavelengths > 550 nm, nor a significant influence on response to blue of a pre-, post-, or simultaneous-irradiation with red or far-red could be observed. Also a dark period was without any effect on the polarotropic response to blue. Growth responses under linearly polarized light are described.

Steiner, A.

doi: 10.1007/BF00388960pmid: 24515859

A series of dose response curves was worked out in the polarotropically active blue and UV spectral region. These dose response curves show changes in slope as a function of wavelength. In blue the slope values are higher than in UV. As a consequence, both the relative height of the peaks in blue and UV and the fine characteristics in blue of the action spectrum calculated on the basis of these dose response curves change decisively with different response levels taken for calculation. Therefore no decision can be made as to what photoreceptor(s) might be involved. Though at medium response levels the action spectra show similarity with action spectra of other blue-UV-mediated photoresponses, which generally are believed as being indicative of some flavin.

Reznik, H.; Lichtenthaler, H.; Peveling, E.

doi: 10.1007/BF00388961pmid: 24515860

1. The plastids of the saprophytic orchid Neottia nidus-avis contain, besides chlorophyll a, all plastidquinones and carotenoids of normal chloroplasts from higher plants. The relative concentrations of plastidquinones and carotenoids are, however, quite different from those in photosynthetically active plant tissue. 2. The plastids of the inflorescences and leaves possess osmiophilic plastoglobuli between the coiled thylakoids. The plastids of the Neottia rhizom have prolamellar body-like structures and also contain plastoglobuli. 3. Thus several observations — coiled thylakoids, lack of chlorophyll b, anormal plastidquinone and carotenoid concentrations — indicate that the thylakoids of Neottia plastids are not fully functional.

Oesch, Franz

doi: 10.1007/BF00388962pmid: 24515861

The low molecular-weight carbohydrates sucrose, d-glucose, d-fructose, myoinositol, O-α-d-galactopyranosyl-(1→1)-myoinositol, raffinose, d,l-inositol, stachyose, α,α-trehalose and d-galactose (in decreasing order of percentage by weight) were isolated from the cambial sap of the beech (Fagus silvatica L.). The acidic compounds glucose-6-phosphate, glucose-1-phosphate, fructose-1,6-diphosphate, malic acid and oxalic acid were also tentatively identified.