Somatic embryogenesis and plantlet regeneration in mango (Mangifera indica L.)

Summary The ‘Carabao’ or ‘Manila Super’ mango (Mangifera indica L.), a virtually neglected fruit before the advent of KNO₃ flower induction in the early 1970s, is now the third leading Philippine export fruit after banana and pineapple. To apply biotechnology for improvement, a reliable embryogenesis and regeneration protocol is required. We have developed a protocol for somatic embryogenesis and plantlet regeneration in mango: eight strains of ‘Carabao’ and two unidentified varieties, PHL 12384 and PHL 12378. Over 40 batches of nucellar explants from immature fruis (0.75–5.0 cm long) were cultured in vitro from April 1999 to April 2000. Two media were used, MMSE. Mango Medium for Somatic Embryo Induction, Proliferation and Germination and MMPR, Mango Medium for Plantlet Regeneration. These are now routinely used. The protocol is reproducible in 14 other varieties of mango. Shifting the base medium from Gamborg's B5 medium to our own formulation. BP medium (Barba and Pate?a's formulation) effectively controlled browning. Browning has limited the successful in vitro culture of many woody species including the mango. Crop Science Society of the Philippines (CSSP) 2001 Best Paper Award, Asian Agriculture Congress, Westin Philippine Plaza, Manila, Philippines, April 24–27, 2001 and Philippine Fruit Association 2000 Best Poster Award, 8th National Symposium. PCARRD, Los Ba?os, Laguna, Philippines, November 14–16, 2000.     

Effects of different methods of acid hydrolysis on the nitrogen distribution in two soils

Summary An inorganic (Bainsville) and an organic (Farnham) soil were hydrolyzed by continuous and stepwise hydrolysis with hot 3N HCl for 1, 2, 3, 4, 11, 15, 18 and 24 h and continuously with hot 6N HCl for 24 h. The following nitrogen forms were determined: total N, hydrolyzable-N, amino acid-N, amino sugar-N and ammonia-N. Proportions of ‘unknown’ N were computed from these data. Continuous hydrolysis with 3N HCl yielded more amino acid-N and less ‘unknown’ N than did stepwise hydrolysis with the same acid strength. But continuous hydrolysis for 24 h with 6N HCl produced more amino acid-N and less ‘unknown’ N than did hydrolysis with 3N HCl by either method. It was estimated that 33 and 54% of the total N in the inorganic and organic soil, respectively, was protein-N. The ‘unknown’ N in the inorganic and organic soil constituted 51 and 37% of the total N, respectively. From our work it appears that the ‘unknown’ N is not proteinaceous. It can be readily degraded chemically and microbiologically to NH₃ and N-gases. More attention needs to be given to identifying the ‘unknown’ N which constitutes a large portion of the total soil-N. A more adequate knowledge of the chemical constitution of the ‘unknown’ soil N may lead to the development of technologies that will make more efficient use of the N in soils.     

Carbohydrates in water-stable aggregates and particle size fractions of forested and cultivated soils in two contrasting tropical ecosystems

Information on changes in storage and loss of soil organic carbon (SOC) when tropical forests are converted to cropland is needed for evaluating soil structural degradation and for selecting appropriate sustainable soil management practices. We evaluated changes in SOC storage of organic carbon and acid-hydrolyzable carbohydrates content of aggregated classes and particle size fractions of adjacent forested and cultivated soils in eight agroecosystems from Ethiopian highlands and Nigerian lowlands. In all agroecosystems, SOC content was two to four times higher in the forested than the cultivated soils. Higher SOC content was found in Ethiopian (20.2–47.3 g.kg^–1) than Nigerian (12.0–24.0 g.kg^–1) forested soils. The magnitude of reduction in SOC and total carbohydrates with cultivation was soil-specific, being generally higher in the sandy than the clayey soils. The smaller aggregate classes (< 1.00 mm) and the sand-sized particles (2000–63 µm) of the forested soils were preferentially enriched in carbohydrates relative to larger aggregates (4.75–1.00 mm). Carbohydrates were more concentrated in the clay-size fraction of the forested than in that of the cultivated soils. Cultivation reduced aggregate stability, increased the proportions of the smaller size aggregates and their associated carbohydrates relative to the forested soils. The susceptibility of the cultivated soils to loss in structural stability reflected this initial aggregation which was greater in the more stable clayey than the fragile sandy soils. The aggregate stability of either the forested or the cultivated soil could not be accounted for by the levels of OC or total carbohydrates in the soil.     

Response of Rhizobium leguminosarum bv phaseoli to acidity

Soil acidity constraints grain legume production in tropical soils, both limiting Rhizobium survival and reducing nodulation. Strains of rhizobia with greater tolerance to hydrogen-ion concentration have been identified, but the basis for strain differences in pH tolerance has yet to be determined. In this study, strains of Rhizobium leguminosarum by phaseoli which differed in their tolerance to acidity were exposed to acid pH, then cell levels of potassium and calcium determined, and specific ‘acid-shock’ proteins identified. Lowering the external pH to 4.6–4.7 resulted in an immediate efflux of calcium from the cell of both acid tolerant and sensitive bean strains. Change in cell potassium levels on exposure to acidity varied with the strain. Strain UMR 1899 and an acid-sensitive mutant derived from it maintained high cytoplasmic potassium at acid pH, whereas an acid-sensitive strain UMR 1632 underwent a marked decline in cell potassium at pH 4.6. Exposure of these strains to pH 4.5 in the presence of [³⁵S]-labeled methionine enhanced production of a number of proteins, while synthesis of other proteins at this pH was significantly reduced. Differences in banding pattern were also evident between UMR1899 and the Tn5-induced pH-sensitive mutant UMR5005 derived from it, and between cells grown in the presence and absence of calcium and phosphorus.     

Morphology of the nervous system of Polychaeta (Annelida)

The article summarizes our up to date knowledge about the morphology of the annelid, especially the polychaete, central and peripheral nervous system. Since the cephalic nervous system was in the focus of controversial discussions for decades, the structure of its neuropile, associated ganglia and nerves is reviewed in detail. The enormous variation of the ventral nerve cord and peripheral nerves is presented as well as a theory how this might have evolved. A ground pattern of the polychaete nervous system is suggested, based on developmental and regeneration studies.     

Report on the Polycystididae (Rhabdocoela, Kalyptorhynchia) from Australia, with the Description of Twelve New Species and Six New Genera

Twelve new species of Polycystididae Graff, 1905 are described from the Australian east coast. Nine of them could not be placed in any of the existing genera, and therefore six new genera are erected. Alchoides n. gen. differs from all other polycystidid genera by the presence of a bundle of glands that opens into the distal part of the male atrium (accessory vesicle type V). Two species are included in the genus, A. alchoides n. sp. and A. dittmannae n. sp., which differ from each other in the shape of the stylet. Ametochus gehrkei n. gen n. sp. can be distinguished from other polycystidids by the presence of a prostate vesicle type III associated with a prostate stylet type III, combined with the presence of an accessory stylet type III, while a prostate stylet type II is lacking. Typical for Arrawarria inexpectata n. gen n. sp. is the combined presence of an armed cirrus with a prostate vesicle type II connected to a prostate stylet type II. Two species are assigned to the new genus Duplexostylus n. gen.: D. rowei n. sp. and D. winsori n. sp. These two species have two unique features: a prostate vesicle type IV directly connected to a prostate stylet type III and an asymmetrical septum that surrounds the proximal part of the male atrium. They can be distinguished from each other by differences in the detailed construction of their stylets. Two new species are placed in the new genus Stradorhynchus n. gen.: S. caecus n. sp. and S. terminalis n. sp. They have unpaired gonads and a prostate vesicle type IV connected to a prostate stylet type IV, which combination of characters makes them unique within the Polycystididae. The two species differ from each other in the shape and size of the stylet. Triaustrorhynchus armatus n. gen., n. sp. is the first species of the Polycystididae to have three types of stylet in the male atrium: a prostate stylet type II, a prostate stylet type III and an accessory stylet type III. Three new species could be placed in existing genera: Cincturorhynchus monaculeus n. sp., Paraustrorhynchus caligatus n. sp. and Polycystis australis n. sp. All three differ from their congeners in the form and dimensions of their stylets. All newly described species are discussed, giving their similarities and differences with resembling species. Austrorhynchus hawaiiensis Karling, 1977 is reported for the first time in Australia, and the Australian population is compared with populations from other regions. The presence of Gyratrix hermaphroditus Ehrenberg, 1831, one new species of Paulodora Marcus, 1948 and a new genus of Typhlopolycystidinae Evdonin, 1977 is mentioned.     

Direct extraction of curvature-based metric shape from stereo by view-modulated receptive fields

Any computation of metric surface structure from horizontal disparities depends on the viewing geometry, and analysing this dependence allows us to narrow down the choice of viable schemes. For example, all depth-based or slant-based schemes (i.e. nearly all existing models) are found to be unrealistically sensitive to natural errors in vergence. Curvature-based schemes avoid these problems and require only moderate, more robust view-dependent corrections to yield local object shape, without any depth coding. This fits the fact that humans are strikingly insensitive to global depth but accurate in discriminating surface curvature. The latter also excludes coding only affine structure. In view of new adaptation results, our goal becomes to directly extract retinotopic fields of metric surface curvatures (i.e. avoiding intermediate disparity curvature).To find a robust neural realisation, we combine new exact analysis with basic neural and psychophysical constraints. Systematic, step-by-step ‘design’ leads to neural operators which employ a novel family of ‘dynamic’ receptive fields (RFs), tuned to specific (bi-)local disparity structure. The required RF family is dictated by the non-Euclidean geometry that we identify as inherent in cyclopean vision. The dynamic RF-subfield patterns are controlled via gain modulation by binocular vergence and version, and parameterised by a cell-specific tuning to slant. Our full characterisation of the neural operators invites a range of new neurophysiological tests. Regarding shape perception, the model inverts widely accepted interpretations: It predicts the various types of errors that have often been mistaken for evidence against metric shape extraction.     

Dormant forms of <Emphasis Type="Italic">Micrococcus luteus</Emphasis> and <Emphasis Type="Italic">Arthrobacter globiformis</Emphasis> not platable on standard media

The colony-forming ability of long (3–9 months) incubated cystlike resting cells (CRC) of the nonspore-forming gram-positive bacteria Micrococcus luteus and Arthrobacter globiformis was studied in this work. The preservation of the CRC proliferative potential as assayed by plating on standard LB agar was shown to depend on the conditions of the formation of the dormant cells. In aged post-stationary cultures of micrococci and arthrobacters grown under carbon and phosphorus limitation the number of colony-forming units (CFU/ml) of CRC decreased in the course of 3–9 month incubation to the level of 10⁶–10⁷ CFU/ml. However, M. luteus CRC obtained under carbon and nitrogen limitation and A. globiformis CRC obtained under nitrogen limitation and starvation completely lost their ability to form colonies on standard solid medium after 4–6 months of incubation and turned into a ‘non-culturable’ (non-platable) state. In this case, the ratio of live cells in the population of M. luteus and A. globiformis ‘non-culturable’ CRCs (determined by the Live/Dead staining test) was 10–44% of the total cell number. To study the possible preservation of proliferative potential in non-platable CRCs, various methods of their reactivation were applied. Although preincubation of CRC suspensions in a buffer solution of 0.1 M K₂HPO₄ (pH 7.4) or in the presence of lysozyme (1 or 10 μg/ml) resulted in increased numbers of live cells (determined by the Live/Dead test) or in disruption of the cell conglomerates, it did not increase considerably the CFU titer on LB medium. Variations in the medium composition, such as addition of sodium pyruvate as an antioxidant or dilution of the medium, promoted the formation of macrocolonies by a small portion of nonplateable CRC of M. luteus (50?80 CFU/ml), whereas the number of the cells capable of microcolony formation (mCFU) was 1.8–6.8 × 10⁵ mCFU/ml, exceeding the CFU titers by four orders of magnitude. The application of semisolid agar and the most probable number (MPN) method was the most efficient for determination of the mCFU titer, and an almost complete reversion of ‘non-culturable’ micrococcal CRCs to microcolony formation was observed (up to 2.3 × 10⁷ mCFU/ml). The usefulness of diluted complete media for the restoration of the colony-forming ability of the dormant forms was confirmed in experiments with ‘nonculturable’ CRCs of A. globiformis. The development of special procedures and methods for determining actively proliferating cells not detected by ordinary methods is of great importance for advanced monitoring studies.     

Insertion of foreign epitopes in HBcAg: how to make the chimeric particle assemble

Summary. Hepatitis B core antigen is one of the most promising protein carriers of foreign epitopes of various human and animal pathogens. Chimeric HBcAg particles can be used as effective artificial immunogenes. Unfortunately, not all chimeric proteins are able to be particulated. The dependence of correct or incorrect folding of chimeric proteins on physical and chemical properties of inserts was studied with the help of ProAnalyst, SALIX and QSARPro computer programs. We have found that insertion of amino acids with high hydrophobicity, large volume, and high β-strand index prevent self-assembling chimeric proteins. These factors are most important for the C-termini of inserts. Recommendations for obtaining correct folding of chimeric HBcAg particles have been given. Received August 8, 1999, Accepted September 26, 1999     

Bio-available amino acids and mineral nitrogen forms in soil of moderately mown and abandoned mountain meadows

Summary. The abandonment of traditional mowing methods of mountain meadows in the Czech Republic at the end of the last century has resulted in secondary re-colonization of these areas. Altered accumulation of plant biomass resulted in a deceleration of N turnover. A mountain meadow may be regarded as a N-limited ecosystem in which plant nutrition is dependent on direct uptake of soil amino acids. The composition and distribution of ammonium ions, nitrate ions and the 16 bio-available proteinaceuous amino acids were investigated in the top 7 cm of the Ah horizon of a Gleyic Luvisol in a long-term moderately mown meadow and an eleven year old, abandoned or uncut meadow. Ammonium N has a dominant role in both ecosystems. The moderately mown meadow showed accelerated N-turnover and higher net ammonization. The plant community showed a dependence on this form. Plant utilization of nitrates and amino acids appeared to be negligible. The uncut or abandoned meadow showed net ammonization from May (start of the experiment) through August, after which plant N-uptake consisted only of amino acids due to microbial immobilization. The release of bio-available nitrogen from spring until the beginning of summer in the Ah horizon was too low to explain total plant N-uptake. Glutamic acid, arginine and aspartic acids had the highest concentrations of any of the amino acids analyzed. Authors’ address: Pavel Formánek, Department of Geology and Pedology, Mendel University of Agriculture and Forestry, Zemedelska 3, 613 00 Brno, Czech Republic     

The Rumor of Globalization: Globalism,Counterworks and the Location of Commodity

This article seeks to document the vernacular perceptions of ‘globalization’ in rural Bengal (India) and, in that connection, seeks to rethink some long-held western notions concerning commodity, consumption, representation, the nature of sociality and the politics of democratic empowerment in the third-world. In the subaltern imaginary, images seem to play a crucial role conductive to empowerment. Also, far from resisting globalization and consumption, the rural poor seems to have assimilated these into their vernacular cosmology. In memoriam: Gourkishore Ghosh (1923–2001) Vernacular intellectual, publicist, crusader for free speech and democracy     

O/N-alkyl and alkyl C are stabilised in fine particle size fractions of forest soils

Carbon stocks and organic matter composition in bulk soils and particle size fractions of Ah horizons from Luvisols, Leptosols and Phaeozems under European beech (Fagus silvatica L.) forest were investigated by elemental analysis, solid state ¹³C nuclear magnetic resonance (¹³C CPMAS NMR) spectroscopy and lignin analysis (CuO-oxidation). Radiocarbon age was used as an indicator for C turnover. The SOM of bulk soils and particle size fractions is dominated by O/N-alkyl C and alkyl C. Compared to sand and silt fractions, clay fractions had lower C/N ratios and ¹⁴C abundances. Aryl C and more specifically phenolic components (O-aryl C) decreased from sand to clay fractions. The concomitant decrease of lignin, determined by CuO oxidation, suggests that a major proportion of O-aryl C can be attributed to lignin. Positive nonlinear relations between the O-aryl C and the C/N ratio reveal the trend of decreasing O-aryl C proportions with increasing decomposition. Although lignin is believed to be highly recalcitrant, only low amounts of lignin are found in the stable clay fractions. In contrast to O-aryl C, the O/N-alkyl C contribution decreased from sand to silt fractions, but increased again in the clay fractions, whereas alkyl C contents exhibited lowest values in the sand fractions. These results are indicative of stabilisation processes operating specifically on polysaccharides and alkyl C, but not on aryl C, through association with the clay fraction.     

Comparative investigations of growth and solvent formation in ‘Clostridium saccharoperbutylacetonicum’ DSM 2152 and Clostridium acetobutylicum DSM 792

The butanol and acetone-producing strain DSM 2152, invalidly described as ‘Clostridium saccharoperbutylacetonicum’ is compared with the type strain C. acetobutylicum, DSM 792, with respect to solvent and acid formation at varying pH values and growth rates. Batch cultures, product-limited chemostat and pH-auxostat cultures were used for characterization. Under all conditions strain DSM 2152 produced much lower amounts of butyric and acetic acids than the type strain. The pH optimum for solvent formation was higher, ie 5.5 instead of 4.5. Solvent formation occurred at higher dilution rates, but below 0.1 h⁻¹ a lower solvent concentration was obtained, indicating that acid production was too low to provide a sufficient amount for acetone formation. The results are discussed in the light of recent publications on the taxonomy of butanol-acetone producing clostridia using 16S rRNA sequence analysis and other nucleic acid data. The presently suggested ‘phylogenetic’ classification of the collective species, C. acetobutylicum, is also reflected in the fermentation characteristics. Received 21 December 1998/ Accepted in revised form 22 January 1999     

Net nitrogen mineralization and net nitrification rates in soils following deforestation for pasture across the southwestern Brazilian Amazon Basin landscape

Previous studies of the effect of tropical forest conversion to cattle pasture on soil N dynamics showed that rates of net N mineralization and net nitrification were lower in pastures compared with the original forest. In this study, we sought to determine the generality of these patterns by examining soil inorganic N concentrations, net mineralization and nitrification rates in 6 forests and 11 pastures 3 years old or older on ultisols and oxisols that encompassed a wide variety of soil textures and spanned a 700-km geographical range in the southwestern Brazilian Amazon Basin state of Rondônia. We sampled each site during October-November and April-May. Forest soils had higher extractable NO₃ ^?-N and total inorganic N concentrations than pasture soils, but substantial NO₃ ^?-N occurred in both forest and pasture soils. Rates of net N mineralization and net nitrification were higher in forest soils. Greater concentrations of soil organic matter in finer textured soils were associated with greater rates of net N mineralization and net nitrification, but this relationship was true only under native forest vegetation; rates were uniformly low in pastures, regardless of soil type or texture. Net N mineralization and net nitrification rates per unit of total soil organic matter showed no pattern across the different forest sites, suggesting that controls of net N mineralization may be broadly similar across a wide range of soil types. Similar reductions in rates of net N transformations in pastures 3 years old or older across a range of textures on these soils suggest that changes to soil N cycling caused by deforestation for pasture may be Basin-wide in extent. Lower net N mineralization and net nitrification rates in established pastures suggest that annual N losses from largely deforested landscapes may be lower than losses from the original forest. Total ecosystem N losses since deforestation are likely to depend on the balance between lower N loss rates from established pastures and the magnitude and duration of N losses that occur in the years immediately following forest clearing.     

Incubation capacity and clutch size determination in two calidrine sandpipers: a test of the four-egg threshold

Several groups of vertebrate taxa, including shorebirds, are unusual in that they produce a fixed number of offspring. The aim of this study was to examine whether the incubation capacity of western sandpipers (Calidris mauri) and semipalmated sandpipers (C. pusilla) limits their maximum clutch size to four eggs. Experimental enlargement of clutch size had no effect on rates of nest abandonment, nest attendance or loss of body mass by incubating sandpipers. The duration of incubation was significantly longer for enlarged five-egg nests, and there were trends towards increased partial clutch loss and asynchrony at hatch, but overall hatching success was unaffected by experimental egg number. I conclude that small, calidrine sandpipers with biparental care are able to compensate for an additional egg in an enlarged nestbowl, despite the constraints of conically shaped eggs and two brood patches. Possibly, shorebirds do not lay more than a fixed clutch size of four eggs because selection on factors acting during egg production or brood-rearing is more important in regulating offspring number. Received: 20 June 1996 / Accepted: 30 September 1996     

Adventitious plant regeneration on leaf explants from adult male kiwifruit and AFLP analysis of genetic variation

The present work reports on a study of plant regeneration carried out with callus from the leaf blades and petioles of field-grown male adult kiwifruit plants (Actinidia deliciosa (Chev.) Liang and Ferguson). The cultivars used were ‘Tomuri’ and clone A, a selected male plant grown in north western Spain. The best shoot induction conditions were obtained in ‘Tomuri’ leaf blades cultured in K(h) medium in the presence of 23 μM Zeatin and 0.1 μM NAA. Under these conditions, more than 80% of organogenic callus induction was observed, with an average of 14 new shoots in the second subculture. The initial length of the shoots affected shoot elongation, which was accomplished by culturing isolated shoots in K(h) medium with half-strength salts, supplemented with 0.4 μM Zeatin and 0.1 μM NAA. A possible detrimental long-term effect of cytokinins on shoot elongation can account for the results, since elongation was not observed until 1 month of culture in elongation medium. For rooting, shoots (1 cm in length) were basally immersed in a 5 mM IBA solution for 15 s, and transferred to half-strength K(h) basal medium. Regenerated plants were acclimated in a sterile peat:perlite substrate for 10 days, and then transferred to soil. AFLP analysis was accomplished with 15 primer combinations from which 13 showed reproducible and well-resolved bands, producing a total of 1321 fragments from which 1281 were polymorphic (97%). A dendrogram was constructed using both monomorphic and polymorphic bands, showing genetic variation among field-grown plants and tissue culture-derived regenerants.     

Difficulties in coupling to conformationally constrained aromatic amino acids

Summary Coupling of amino acids to 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid (Tic) and 1,2,3,4-tetrahydro-7-hydroxyisoquinoline-3-carboxylic acid (HOTic) is difficult. In model experiments, use of 1-hydroxy-7-azabenzotriazole (HOAt) in combination with eitherN,N-diisopropylcarbodiimide (DIC) orO-(7-azabenzotriazol-1-yl)-1,1,3,3-tetramethyluronium (HATU) for activation was effective in solving coupling difficulties. Based on this finding, HOTic was then incorporated into the 20–31 fragment of human epidermal growth factor (hEGF). [Abu^{20, 31},HOTic²²]hEGF(20–31)-NH₂ was shown to be a ‘difficult sequence’, but replacement of the Tyr at position 29 with HOTic facilitates the complete dodecapeptide synthesis.     

Conservation and documentation of the medicinal plant resources of India

In India, activities in the field of medicinal plants, including conservation of germplasm, have been enhanced significantly during the past couple of decades and a huge volume of data is being generated out of these works. For maintaining the records in a consolidated form, documentation is required to store and manage all information on the related studies. In accordance with the implementation of various plans and programmes, some pioneer organisations started developing databases on medicinal plants. Based on the knowledge on contemporary works, as collected from published literature and websites, this article presents information on current activities in India in two important aspects of the field, namely, (1) conservation of medicinal plants; and (2) management of data generated from such studies. Another important aspect of the article is the announcement of a plant conservation related software, ‘PlantCon’. This digitised database contains data of 40 selected nationally prioritised medicinal plants (list enclosed). The notable difference of ‘PlantCon’ from other databases lies in its conservation-related information which is up-to-date and covers a wide area of Indian geographical sites. The database provides information in a user-friendly manner.     

Soil Patches of Inorganic Nitrogen in Subtropical Brazilian Plant Communities with Araucaria angustifolia

One-year old tubers of two hybrid calla lily (calla) cultivars (Zantedeschia ‘Pot of Gold’ and ‘Majestic Red’) were inoculated with the arbuscular mycorrhizal fungus (AMF), Glomus intraradices, or not, and grown at three different rates of phosphorus (P) supply to asses the effects of AMF-inoculation on plant development (time of shoot emergence and flowering), flowering (number, length and rate of flowering), and tuber biomass and composition over two growing cycles (2002, 2003). Tubers and flowers of calla responded differently to AMF inoculation. Differences in mycorrhizal responsiveness between cultivars was related to differences in P requirements for flower and tuber production, and the influence of P supply on resource allocation to different reproductive strategies. Inoculation increased shoot production and promoted early flowering, particularly in 2003. Inoculated plants also produced larger tubers than non-inoculated plants, but only increased the number of flowers per plant in 2003. High P supply also increased tuber biomass, but decreased the number of flowers per plant in 2002. Plants grown at a moderate P-rate, produced the most flowers in 2003. For ‘Majestic Red’, benefits from AMF were primarily in terms of tuber yield and composition, and AMF effects on marketable flower production could potentially have negative impact on production strategies for growers. Inoculation of ‘Pot of Gold’ primarily influenced flower production and aspects of tuber quality that caused detectable enhancement of tuber yield and flowering in the second growing cycle following inoculation (2003). The results of this study show that the responses of calla to AMF are partially a function of how nutrient supply alters resource allocation to sexual and vegetative reproduction. Whether AMF-induced changes in resource allocation to flowering and tubers significantly alters commercial productivity and quality of calla depends on the crop production goals (e.g. tubers, cut flowers or potted plants). The U.S. Government’s right to retain a non-exclusive, royalty free licence in and to any copyright is acknowledged.     

Utilisation of Ulva rigida biomass in the Venice Lagoon (Italy): biotransformation in compost

In the Venice Lagoon (Italy), about 10⁶ t (wet weight) of Ulva rigida biomass are produced annually as one of the major results of eutrophication. Harvests have been initiated to reduce negative impacts of this biomass, however, due to the high costs of such effort, only 40 000 t yr^-1 are currently being collected. At the moment, biotransformation into compost seems to be the only feasible technology for utilising large quantities of Ulva biomass. We describe and discuss here a successful composting strategy together with the chemico-physical and microbiological characteristics of the resultant composts. Our composting experiments were conducted at a scale of 20 t. The composting technology utilises large proportions (70–90%) of Ulva biomass and results in a valuable, high-quality end product (compost and compost-based products). This process and the resulting products represents a relatively simple way of utilising the Ulva biomass produced annually in the Venice Lagoon.