Long-term biological effectiveness of Pochonia chlamydosporia var. catenulata against Meloidogyne incognita infection in a crop rotation systemi

The aim of this study was to determine the effectiveness of Pochonia chlamydosporia var. catenulata and the bacteria Tsukamurella paurometabola strain C-924 (HeberNem?), to control Meloidogyne incognita infection in a crop rotation system (cucumber, tomato and pepper) under greenhouse production during six crop cycles. We determined gall index, prevalence, intensity of disease, and number of juvenile nematodes in soil. At the end of the sixth cycle, plants protected with P. chlamydosporia showed a reduction in gall index (≤2), prevalence, and median (42%) intensity of disease similar or more pronounced than those observed in plants protected with T. paurometabola (80%). Both treatments were more efficient at reducing galling than at reducing prevalence and therefore reduction of intensity of disease was mainly due to the reduction in galling. The hydrolytic activity of P. chlamydosporia and its resistant spores make this fungus one of the best options for the long-term control of RKNs by decreasing egg masses or galls. Pochonia chlamydosporia var. catenulata is an important part of a potential biological control strategy in rotation systems of vegetable crop and can be used for long-time IPM strategies in Cuba and the Caribbean.     

Mineralogy and factors controlling charge development of three Oxisols developed from different parent materials

Three Oxisols, developed from serpentinite (Sungai Mas Series), basalt (Kuantan Series) and andesite (Segamat Series), selected to represent the most common Oxisols in Malaysia were sampled and studied. The objectives of this study were: (i) to determine mineralogical composition and factors responsible for changes in point of zero charge (pH₀) of the variable charge component of three Oxisols; (ii) to use pH₀ values to assess degree of chemical weathering; and (iii) to determine the magnitude of variable charge using corrected back-titration technique. The mineralogical composition was determined by X-ray diffraction analysis (XRD). The pH₀ was determined by potentiometric titration in different electrolyte strengths. The magnitude of variable charge generation as a function of soil pH was measured using corrected back-titration to allow elimination of charge overestimation caused by solid dissolution and hydrolysis reactions. The results showed that the mineralogical composition were similar (kaolinite, goethite, hematite and gibbsite) between profiles but different in proportion, except for gibbsite which was absent in the andesite-derived soil. The sequential removal of soil organic matter (SOM), iron oxides and SOM together with iron oxides resulted in the changes of pH₀ from 3.9–5.7 to 5.3–6.7, 2.6–3.7 and 3.3–4.5, respectively. These pH₀ changes indicate SOM and sesquioxides are masking mineral surfaces and are factors responsible for lowering and increasing pH₀ values, respectively. Regression correlation (R² = 0.87^??) showed that for every 1% organic C may decrease 1.0 unit of pH₀ value. The pH₀ values, after SOM removal, are in the order of Sungai Mas ～ Segamat > Kuantan Series. This suggests that the serpentinite and andesite-derived soils have achieved a relatively similar degree of chemical weathering and they are more weathered than the basalt-derived soil. The charge measured by corrected back-titration is 1.5–3.8 cmol_c kg^? 1 at pH 4.5 and increases to 4.2–10.8 cmol_c kg^? 1 at pH 6.5, indicating that the three Oxisols mainly bear variable charge. Charge overestimation resulted from dissolution and hydrolysis reactions during potentiometric titration ranges from 36 to 160%, depending on pH values (the lower the pH the higher is the overestimation). Hence, back-titration is a reliable technique to correct charge overestimation when using the traditional potentiometric titration for highly weathered tropical soils.     

Neoechinorhynchus (Neoechinorhynchus) zabensis sp. n. (Acanthocephala: Neoechinorhynchidae) from freshwater fish in northern Iraq

Neoechinorhynchus (Neoechinorhynchus) zabensis sp. n. (Acanthocephala: Neoechinorhynchidae) is described from Capoeta damascina (Valenciennes, 1842) (type host) and Capoeta trutta (Heckel, 1843) in the Greater and Lesser Zab Rivers, northern Iraq. The new species is unique among all other species of the genus by its characteristic paired para-vaginal muscular appendage and fragmented giant nuclei in the lemnisci. Eleven of the other 88 valid species of Neoechinorhynchus and N. zabensis have middle and posterior hooks of equal length. However, N. zabensis is distinguished from the others by size of trunk, proboscis, proboscis hooks and lemnisci, number of giant nuclei, position of female gonopore, and geographical and host distribution. It is also distinguished from six other species of Neoechinorhynchus previously reported from Iraq. Other distinguishing features are also included.     

Efficacy of VP2 protein expressed in E. coli for protection against highly virulent infectious bursal disease virus

The ability of a heat-inactivated whole virus from a highly virulent infectious bursal disease virus (hvIBDV) and VP2 protein from hvIBDV expressed in E. coli provided protection against a hvIBDV challenge in specific-pathogen-free (SPF) chickens. Six out of seven chickens that were injected three times with crude VP2 protein developed significant antibody titer against IBDV. However, only four out of the seven chickens survived the hvIBDV challenge. Despite showing low antibody titer profiles, all chickens immunized with the heat-inactivated whole virus also survived the challenged with hvIBDV. However, all of these chickens had bursal atrophy and mild to moderate depletion of lymphocytes. Thus, antibodies raised against IBDV VP2 protein expressed in E. coli and denatured IBDV proteins induced some degree of protection against mortality but not against bursal damage following challenge with hvIBDV.     

Ability of plant-based surface technology to improve urban water cycle and mesoclimate

The presented study proposes a technology that could be used in developing a stormwater management strategy. The research was conducted under the hypothesis that a plant-based surface system (PBSS) can increase the capacity of sealed urban surfaces, for example, along railway tracks, to reduce runoff volume, to increase evaporation and consequently to improve the mesoclimate. To test this statement, water retention capacity, runoff–precipitation ratio, runoff delay and evapotranspiration performance were determined for different time periods (rainwater events, daily, monthly, seasonally, yearly, and throughout the entire measuring period of 18 months) by means of a measurement strategy implemented in selected urban traffic areas of Berlin, Germany, that contained railway tracks. Additionally, a computation of the air humidity improvement of an urban test location based in measurements is presented. The main elements of the tested PBSS were a 2 cm thick vegetation mat and a 20 cm thick drainage layer. The measurement strategy for the hydrological characterization included the installation and use of weighable lysimeters, rain gauges and runoff volume counters. The runoff volume determined in some summer months for the PBSS technology amounted to 9% of precipitation. The evaporation performance in these months amounted to 100% of precipitation. These results were compared with the corresponding calculated values for an asphalt surface: runoff 70–80% of precipitation and evaporation performance of 20–30% of precipitation. The study provides evidence of the positive effect of this technology on the local water balance of the treated sealed areas.     

Flood tolerance of four tropical tree species

Many seasonally flooded habitats in the tropics are dominated by one or a few tree species. We tested the hypothesis that the inability to tolerate flooding restricts most species from becoming established in flood-prone habitats. We compared morphological and physiological responses to flooding in seedlings of Prioria copaifera Griseb., a species that forms monodominant stands in seasonally flooded habitats, and in three species confined to flood-free sites; namely, Calophyllum longifolium Willd., Virola surinamensis Aubl. and Gustavia superba (H.B.K.) Berg. Flooding reduced photosynthesis at Day 45 in all species by 10-30%. By Day 90, photosynthesis returned to the control rate in Prioria, but not in the other species. Flooding reduced stomatal conductance by 25-35% in all species except Calophyllum, and it reduced leaf area growth by 44% in Virola, but not in the other species. All species survived 90 days of flooding without mortality, leaf chlorosis, leaf necrosis, or leaf abscission. Flooding reduced root:shoot ratio significantly in Gustavia and Calophyllum, but not in the other species, and it reduced maximum root depth by 29% in Prioria, but by 61% or more in the species from flood-free habitats.     

Interspecific variation in xylem vulnerability to cavitation among tropical tree and shrub species

In tropical moist forests, seasonal drought limits plant survival, productivity and diversity. Drought-tolerance mechanisms of tropical species should reflect the maximum seasonal water deficits experienced in a particular habitat. We investigated stem xylem vulnerability to cavitation in nine tropical species with different life histories and habitat associations. Stem xylem vulnerability was scored as the xylem water potential causing 50 and 75% loss of hydraulic conductivity (P50 and P75, respectively). Four shade-tolerant shrubs ranged from moderately resistant (P50=-1.9 MPa for Ouratea lucens Kunth. Engl.) to highly resistant to cavitation (P50=-4.1 MPa for Psychotria horizontalis Sw.), with shallow-rooted species being the most resistant. Among the tree species, those characteristic of waterlogged soils, Carapa guianensis Aubl., Prioria copaifera Griseb. and Ficus citrifolia Mill., were the most vulnerable to cavitation (P50=-0.8 to -1.6 MPa). The wet-season, deciduous tree, Cordia alliodora (Ruiz and Pav.) Oken., had resistant xylem (P50=-3.2 MPa), whereas the dry-season, deciduous tree, Bursera simaruba (L.) Sarg. was among the most vulnerable to cavitation (P50=-0.8 MPa) of the species studied. For eight out of the nine study species, previously reported minimum seasonal leaf water potentials measured in the field during periods of drought correlated with our P50 and P75 values. Rooting depth, deciduousness, soil type and growth habit might also contribute to desiccation tolerance. Our results support the functional dependence of drought tolerance on xylem resistance to cavitation.     

A new ent-kaurane diterpenoid from Rabdosia pseudo-irrorata

A new kaurenoid, ent-3β,7α,14β-trihydroxykaur-16-ene-12,15-dione (1), named pseurata G, was isolated from the ethanol extract of the whole plant of Rabdosia pseudo-irrorata.     

Diversity,conservation status and threats to native oysters (Ostreidae) around the Atlantic and Caribbean coasts of South America

• 1. Despite the extensive literature on the ecology, systematics and culture of oysters worldwide, an assessment of their diversity, distribution and conservation status for the Atlantic and Caribbean coasts (i.e. depth <50 m) of South America is lacking. Such information is crucial because of the increasing coastal development that threatens most nearshore habitats throughout the region.
• 2. The available information on oysters on Atlantic and Caribbean coasts is reviewed with a focus on identifying regional conservation priorities based on ecological and socio‐economic importance, as well as the magnitude of current or potential threats faced by oyster populations. The current status of α‐ taxonomy within the Ostreidae was also examined.
• 3. Ten species of native Ostreidae (plus three introduced species) inhabit the coastal waters of the Atlantic and Caribbean coasts of South America.
• 4. Oyster species were ranked according to their biological/ecological and socio‐economic value and conservation status within 10 distinct ecoregions. Crassostrea gasar in the Eastern Brazil ecoregion, C. rhizophorae in the Central Caribbean ecoregion and Ostrea puelchana in the North Patagonian Gulfs ecoregion should receive the highest priority for immediate conservation action due to extensive loss of mangrove habitat in the two former regions and evidence of decline of one of the most important populations for the latter. The need for a standardized methodology to assess the status of oyster populations throughout the ecoregions is identified.
• 5. On a local scale, the allocation of territorial use rights for fisheries under a collaborative/voluntary community framework is strongly advocated to fulfil management, conservation and poverty alleviation goals in these developing countries.

Copyright © 2008 John Wiley & Sons, Ltd.     

Underutilized agroforestry food products in Amazonas (Venezuela): a market chain analysis

The worlds’ current food production system is focused on a limited number of crops. However, international food demand is increasingly looking for more diversified supplies. In the Venezuelan State Amazonas, the Piaroa indigenous people collect and cultivate several indigenous species with local, regional, national and even international potential. A participatory approach was used to select, in cooperation with these Piaroa people, a list of products for in-depth economic analysis and for introduction in agroforestry trials in a later phase. Seven agroforestry food products of this list were identified as underutilized. Primary data collected through consumer and trader surveys on the local markets and participatory exercises in selected Piaroa communities revealed that the main causes of underutilization are the general lack of transport, processing and market infrastructure in Amazonas; the lack of demand, due to a lack of product information; the lack of market information and cooperation between the different market chain actors; and the low productivity of the traditional slash and burn plots. Solutions to overcome the infrastructural constraints are sought by looking at the example set by a local NGO.