Optimum utilization of sewage sludge of low and high metal content for grain production on arid lands

Summary Two municipal sludges, one from a highly industrialized city, Chicago, Il, and another from a little industrialized, highly agricultural area, Tucson, AZ are compared for winter barley production on Pima c 1 (Typic torrifluvent). Both sludges were responsible for highly significant additions of Zn, Cu, Ni, Cd and P to the soil each year when applied at the rates of 100 mt/ha singly and 20 mt/ha each year for 4 years. Nitrogen responses for barley straw and grain were observed from both sludges. Tucson sludge appears to be attractive as a potential fertilizer, not only as an NPK source, but also for its organic matter and minimal amounts of heavy metals. The Chicago sludge with relatively high levels of heavy metals, particularly Cd, appears poorly suited as a fertilizer, if used for an extended period of time, because of the plant's tendency to take up elevated levels of certain heavy metals. Some parts of barley plants proved to be a better indicator of heavy metal uptake and concentration than others. The diagnostic-tissue test promises to be a useful tool to warn against undesirable accumulation of heavy metals. Fortunately, when compared with other plant parts, the heavy metal in grain was the least altered as a result of continued sewage sludge use on arid land. The soil's neutral to slightly alkaline pH and the presence of lime throughout the soil profile appeared to be critical factors in keeping plant uptake of heavy metals relatively low as compared with soils of other climates.     

Some aspects of the natural history and food selection ofAvahi laniger

Two groups ofAvahi laniger were studied in the Forêt de Analamozoatra near Perinet in the eastern rainforest of Madagascar from August to October 1984. Overlap between the home ranges of neighbouring groups ofA. laniger was minimal. Group size ranged from one to four individuals with a median group size of two. In four out of ten groups a baby was born between August and September.A. laniger were most active after dusk and before dawn. They had an extended resting period around midnight. Their diet consisted mostly of leaves from at least 17 different plant species. They also ate flowers. Fruit eating was recorded twice. Leaves eaten had high contents of protein and sugar but did not contain alkaloids. The concentration of condensed tannins did not differ between food items and non-food items. There was no indication of competition with other prosimians that might explain their nocturnality.     

Regeneration of peach plants from callus derived from immature embryos

Summary Peach plants were repeatedly regenerated from immature embryos but not from callus derived from mature embryos. A white, nodular, highly regenerative callus was obtained when friable, primary callus from immature embryos was transferred from medium containing 4.5 M 2,4-dichlorophenoxyacetic acid and 0.44 M benzyladenine (BA) to media containing 0.27 M -naphthaleneacetic acid (NAA) and 2.2 M BA. This callus retained its morphogenetic potential for a minimum of three subcultures. Green nodular callus, that lacked regenerative capacity, was produced from primary callus derived from mature embryos. Maximum regeneration of shoots occurred when highly regenerative callus was transferred to a medium in which the NAA concentration was reduced five times and the BA concentration was increased two times. Regenerated shoots were rooted in the dark on a medium containing 28.5 M indoleacetic acid. Cytogenetic analysis of regenerated plants indicated that all plants were diploid, 2n = 2x = 16. Phenotypic evaluation of regenerated plants, grown under field conditions, is now in progress.     

Non-oncogenic plant vectors for use in the agrobacterium binary system

Summary Agrobacterium strains harbouring the T-region and the virulence-region of the Ti plasmid on separate replicons still display efficient T-DNA transfer to plants. Based on this binary vector strategy we have constructed T-region derived gene vectors for the introduction of foreign DNA into plants. The vectors constructed can replicate in E. coli, thus the genetic manipulations with them can be performed with E. coli as a host. They can be transferred to Agrobacterium as a cointegrate with the wide host range plasmid R772. Their T-regions are transferred to plant cells from Agrobacterium strains conferring virulence functions.The plasmid pRAL 3940 reported here is 11.5 kb large, contains a marker to identify transformed plant cells and unique restriction sites for direct cloning of passenger DNA, flanked by the left- and right-hand border fragments of the T-region (including the 25 bp border repeats). The plasmid is free of onc-genes. Therefore, is does not confer tumorigenic traits on the transformed plant cells and mature, fertile plants can thus be regenerated from them.     

Positioning of protein-coding genes on the soybean chloroplast genome

Seven major plastid protein encoding genes were positioned on the soybean chloroplast DNA by heterologous hybridization. These include the genes for the alpha, beta and epsilon subunits of the CF₁ component of ATP synthase (atpA, atpB and atpE respectively), for subunit III of the CF₀ component of ATP synthase (atpH), for the cytochrome f (cytF), for the ‘32 Kd’ thylakoid protein (psbA), and for the large subunit of ribulose-1,5-bisphosphate carboxylase-oxygenase (rbcL), all of which map in the large single copy region. The atpB, atpE and rbcL genes are located in the region adjacent to one of the segments of the inverted repeat. The genetic organization of the soybean chloroplast DNA is compared to that of other plastid genomes.     

Similarities in the genomic sequence and coat protein structure of plant virsuses

The genomic sequences of several RNA plant viruses including cucumber mosaic virus, brome mosaic virus, alfalfa mosaic virus and tobacco mosaic virus have become available recently. The former two viruses are icosahedral while the latter two are bullet and rod shaped, respectively in particle morphology. The non-structural 3a proteins of cucumber mosaic virus and brome mosaic virus have an amino acid sequence homology of 35% and hence are evolutionarily related. In contrast, the coat proteins exhibit little homology, although the circular dichroism spectrum of these viruses are similar. The non-coding regions of the genome also exhibit variable but extensive homology. Comparison of the brome mosaic virus and alfalfa mosaic virus sequences reveals that they are probably related although with a much larger evolutionary distance. The polypeptide folds of the coat protein of three biologically distinct isometric plant viruses, tomato Bushy stunt virus, southern bean mosaic virus and satellite tobacco necrosis virus have been shown to display a striking resemblance. All of them consist of a topologically similar 8-standard β-Barrel. The implications of these studies to the understanding of the evolution of plant viruses will be discussed.     

Search for promoter sites of prokaryotic DNA using learning techniques

Using learning techniques previously described in this journal, we have built an expert system able to point to the start DNA point of a sequence and therefore to recognize a promoter. However, to build this system, we have focused on the TATA box and its environment. We have used this expert system to look for new promoters and also to construct new promoters. The results obtained are discussed.     

The morphology and anatomy ofHydrastis (Ranunculales): Systematic reevaluation of the genus

Evidence from morphology and anatomy (including embryology), as well as from palynology, chemistry and cytology, indicates thatHydrastis is quite divergent from Ranunculaceae (in which the genus has been most often included) as well as from both Glaucidiaceae and Berberidaceae. Distinctive features ofHydrastis, which demarcate it from Ranunculaceae but which are sometimes shared by Berberidaceae, are: the unique mode of origin of the vascular supply to stamens and carpels; the micropyle being formed by both integuments; the xylem not V-shaped in cross section; scalariform vessel perforations present; haploid chromosome number 13; pollen tectum consisting of a compound layer of striae; leaf mesophyll not differentiated; the unique course of stem medullary bundles; D-galactose present. Its distinctive higher haploid chromosome number, as well as its many less-specialized character states (in floral structure, leaf anatomy, and xylem and vessel morphology), suggest thatHydrastis is a relictual primitive group which diverged early from a common ancestral stock of Ranunculaceae, Berberidaceae and probably of Circaeasteraceae; at least some of the features shared byHydrastis and one or another of the families concerned seem to be a heritage from their common ancestor. We propose a reestablishment of a monotypic family, Hydrastidaceae.     

Genetic variation and divergence of the sibling pair of cyprinid fishes, Notropis cornutus and N. chrysocephalus

Horizontal starch gel electrophoresis was used to estimate the amount of genetic divergence between Notropis cornutus and N. chrysocephalus. Measures of genetic identity (1) and distance (D) were 0.881 and 0.127 ± 0.055 (s.e.), respectively. These estimates correspond more closely to the sibling species status of these taxa than other previously reported estimates. Notropis cornutus was found to be significantly more variable than N. chrysocephalus electrophoretically and morphologically. Assuming the existence of an electrophoretic clock, the time of divergence was calculated to be roughly 1.9–2.5 million years. This estimate corresponds very closely to a previously hypothesized late Pliocene divergence.     

Climate and plant distribution at global and local scales

This paper investigates, with predictive models, the utility of ecophysiological responses to climate as predictors of plant distribution. At the global scale responses to extreme minimum temperatures and to the hydrological budget effectively predict the distribution limits of the major vegetation types of the World. A minimum temperature of -15°C, for example, appears critical in controlling the poleward spread of vegetation that is dominated by evergreen broadleaved species; however, the presence or absence of more frost resistant species, such as those that are deciduous broadleaved, is not obviously explained in terms of extremes of climate. In such cases, predicting the competitive relationships between species is necessary and dependent on the climatic sensitivity of population dynamics.We are grateful to Hans de Kroon for discussions on the application of matrices to ecology.