Anatomical and ultrastructural examination of adventitious root formation in stem slices of apple

Adventitious root formation in vitro in 1-mm stem slices cut from microshoots of apple cv. Jork 9 was studied using light and electron microscopy. When indole-3-butyric acid (IBA) had been added to the medium, starch grains accumulated during the first 24 h of culture in cells of the cambial region and in cells in the vicinity of vascular tissue and in the primary rays. This accumulation occurred only in the basal part of explants. After that, the nuclei in these cells were activated, and the density of the cytoplasm and the number of cell organelles increased, whereas starch was broken down. Cambium cells started to divide transversely and at 96 h, after several divisions, a continuous ring of isodiametric cytoplasmic cells had appeared around the xylem near the basal cutting surface. The cells in this ring were rich in cell structures, and did not contain large starch grains and a central vacuole. Root meristemoids regenerated from the portions of the ring that were localized in the primary rays. From the other cells in the ring, callus developed. The meristemoids did not grow into the direction of the epidermis as in shoots, but along the vascular bundles. After emergence from the cutting surface, the meristemoids were transformed into small, dome-like primordia. They developed a typical root apex with root cap, root ground meristem and tracheid connection with shoot vascular tissue. This revised version was published online in July 2006 with corrections to the Cover Date.     

Cytokinin biosynthesis in plant tumour tissues

A range of endogenous cytokinins have been identified inDatura crown-gall tissue by GC-MS. Incorporation of [³H]adenine into zeatin riboside, zeatin and its nucleotide(s) is also shown. Metabolism studies usingcis- andtrans-isomers of zeatin riboside indicate that interconversion of the two isomers does not occur in this tissue. Data on the identity of major endogenous cytokinins in a genetic tumour line of tobacco is also provided.     

Respiratory control determines respiration and nitrogenase activity of Rhizobium leguminosarum bacteroids.

The relationship between the O2 input rate into a suspension of Rhizobium leguminosarum bacteroids, the cellular ATP and ADP pools, and the whole-cell nitrogenase activity during L-malate oxidation has been studied. It was observed that inhibition of nitrogenase by excess O2 coincided with an increase of the cellular ATP/ADP ratio. When under this condition the protonophore carbonyl cyanide m-chlorophenylhydrazone (CCCP) was added, the cellular ATP/ADP ratio was lowered while nitrogenase regained activity. To explain these observations, the effects of nitrogenase activity and CCCP on the O2 consumption rate of R. leguminosarum bacteroids were determined. From 100 to 5 microM O2, a decline in the O2 consumption rate was observed to 50 to 70% of the maximal O2 consumption rate. A determination of the redox state of the cytochromes during an O2 consumption experiment indicated that at O2 concentrations above 5 microM, electron transport to the cytochromes was rate-limiting oxidation and not the reaction of reduced cytochromes with oxygen. The kinetic properties of the respiratory chain were determined from the deoxygenation of oxyglobins. In intact cells the maximal deoxygenation activity was stimulated by nitrogenase activity or CCCP. In isolated cytoplasmic membranes NADH oxidation was inhibited by respiratory control. The dehydrogenase activities of the respiratory chain were rate-limiting oxidation at O2 concentrations (if >300 nM. Below 300 nM the terminal oxidase system followed Michaelis-Menten kinetics (Km of 45 +/- 8 nM). We conclude that (i) respiration in R. leguminosarum bacteroids takes place via a respiratory chain terminating at a high-affinity oxidase system, (ii) the activity of the respiratory chain is inhibited by the proton motive force, and (iii) ATP hydrolysis by nitrogenase can partly relieve the inhibition of respiration by the proton motive force and thus stimulate respiration at nanomolar concentrations of O2.     

A preliminary assessment of congruence between biodiversity patterns in Afrotropical forest birds and forest mammals

Burgess, N., de Klerk, H., Fjeldsá, J., Crowe, T. & Rahbek, R. 2000. A preliminary assessment of congruence between biodiversity patterns in Afrotropical forest birds and forest mammals. Ostrich 71 (1 & 2): 286–291.

Databases compiled for forest birds and forest mammals in the Afrotropics were tested for congruence of overall patterns and hotspots of species richness and endemism. We also looked at how well a near-minimum set of priority areas for one taxon catered for the second taxon. Overall species richness and richness hotspots of forest birds were significantly correlated with those of forest mammals, as was the case for overall endemism. Endemism hotspots for forest birds and mammals were not significantly correlated. The near-minimum set for forest birds represented 136 (76.5%) forest mammal species. The near-minimum set for forest mammals represented 350 (93.62%) forest bird species. However, to represent all forest mammals three times each, 51 grids were needed in addition to the 78 chosen as a near-minimum set for forest birds, and to represent all forest birds three times each, 43 more grids were needed in addition to the 80 selected for forest mammals. There is some congruence between the patterns of richness, endemism and near-minimum sets for forest birds and mammals in the Afrotropics, but the one taxon does not provide the ideal conservation solution for the other. Further refinement of the databases used in this paper would allow for more rigorous testing of congruence between these two groups.     

The Distress Thermometer and Its Validity: A First Psychometric Study in Indonesian Women with Breast Cancer

Purpose

This study aims to translate the Distress Thermometer (DT) into Indonesian, test its validity in Indonesian women with breast cancer and determine norm scores of the Indonesian DT for clinically relevant distress.

Methods

First, the original version of the DT was translated using a forward and backward translation procedure according to the guidelines. Next, a group of 120 breast cancer patients who were treated at the Outpatient Surgical Oncology Clinic in Hasan Sadikin Hospital in Indonesia completed a standard socio-demographic form, the DT and the Problem List, the Hospital Anxiety and Depression Scale (HADS) and the WHO Quality of Life (WHOQOL-BREF).

Results

Receiver operating characteristic (ROC) curve analyses identified an area under the curve = 0.81 when compared to the HADS cutoff score of 15. A cutoff score of 5 on the DT had the best sensitivity (0.81) and specificity (0.64). Patients who scored above this cutoff reported more problems in the practical, family, emotional, spiritual/religious and physical domains (30 out of 36 problems, p-value<0.05) than patients below the cutoff score. Patients at advanced stages of cancer experienced more emotional and physical problems. Patient''s distress level was negatively correlated with overall quality of life, general health and all quality of life domains.

Conclusions

The DT was found to be a valid tool for screening distress in Indonesian breast cancer patients. We recommend using a cutoff score of 5 in this population.     

Effects of light and regulators on senescence-related changes in soluble proteins in detached oat (Avena sativa L.) leaves

The rate of senescence and the two-dimensional pattern of soluble proteins from detached oat leaves senescing in either darkness or light were analyzed, and compared to those of leaves in which senescence was delayed by application of the cytokinin benzyladenine or enhanced through the action of abscisic acid.Senescence of detached leaves in light did not differ significantly from senescence in attached leaves on intact plants. In darkness, protein was lost at a higher rate than in light, but several individual proteins showed relative increases. Notably, proteins previously characterized as high-molecular-weight proteins and senescence-associated proteins (Klerk et al., 1992) increased. Changes observed during incubation in light or darkness appeared to be related to this condition rather than the rate or progress of senescence. Cytokinins delayed and abscisic acid accelerated the changes in protein pattern compared to water. Beside changes previously identified in leaves senescing on the plant, detached leaves show alterations that reflect their condition of incubation rather than their developmental progress.Abbreviations 2D-PAG two-dimensional polyacrylamide gel electrophoresis - ABA abscisic acid - BA N⁶-benzyladenine - BSA bovine serum albumin - EDTA ethylenediamine tetraacetic acid - IEF isoelectric focusing - Rubisco ribulosebisphosphate carboxylase/oxygenase - SDS sodium dodecyl sulfate - Tris tris (hydroxymethyl) aminomethane     

7. SHORT NOTES

Randall, R. and Ross, G. J. B. 1979. Increasing population of Cape Gannets on Bird Island, Algoa Bay, and observations on breeding success. Ostrich 50:168-175.

The South African Gannet Sula capensis on Bird Island has doubled in numbers between 1956 and 1974 and the process is continuing. The increase is similar to that of the two closely related species S. serrator and S. bassana. We estimated from the colony surface area and nest density that the number of birds with nests in 1974/5 was approximately 77 000. Making allowance for non-breeders, there were about 100 000 adults in 1974/5. Guano harvests from 1938–75 show considerable annual fluctuations with an overall downward trend. Poor agreement was found when relating guano harvests to population estimates, when the latter are gauged by colony surface area. We suggest that guano harvests are not good indicators of gannet population trends on Bird Island, primarily because of harvesting methods and environmental conditions. The number of chicks which fledged in the 1976/7 season in a section of the colony was far fewer than expected, even when allowances were made for egg-loss and chick mortality. A combination of heavier-than-usual rainfall and poor management techniques have resulted in high egg-loss and low chick numbers.