Local Ecotypes Research Articles

A reassessment of the prevalent organic solutes constitutively accumulated and potentially involved in osmotic adjustment in pear leaves

In higher plants, osmotic adjustment at the various levels of plant organization is partly achieved through accumulation of a range of osmolytes especially LMW organic solutes often termed as osmotic solutes. A metabolite profiling of crude extracts of mature pear leaves of a range of 8 Pyrus genotypes was performed using current HPLC, UPLC and 1H NMR spectroscopy techniques in order to identify such putative compounds. Using as variables the concentrations of 45 identified substances and those of a restricted number of unknowns, all belonging to LMW carbohydrates, polyols, organic acids, amino acids and phenolics on the one hand, and the varieties investigated as individuals on the other, we generated a set of data analyzed further by PCA. Those varieties were discriminated into three clusters respectively comprised of the four Asian varieties, the European variety Williams grafted onto 4 different rootstocks, and the two other European varieties Conference and Angelys. These metabolic phenotypes were shown to rely more on scion genotypes than on rootstocks. High to very high amounts of sorbitol (average content of 363 μmol g −1 DW) associated with low amounts of mannitol and myo-inositol were found in all genotypes as well as in a local ecotype of P. communis where the hexitol accounted for 7.3% DW. Sorbitol actually represented up to 30-40% of the total osmotically active organic solutes accumulated in the set of pear leaves investigated, and it was shown to be significantly more abundant in the variety Williams than in Asian ones ( p < 0.01). In contrast, the other well-known compatible solute glycine betaine, barely detectable using 1H NMR spectroscopy or HPLC, occurred in leaves of all pear varieties at weak levels lower than 2 μmol g −1 DW which suggested a minor role in osmotic adjustment. Its amount does not seem to be altered in response to an osmotic upshift applied to detached leaves or to depend on exogenously supplied ABA. For non-sustantiated reasons, these results are in contrast with those showing elsewhere very high accumulation of GB in the Asian genotype Su li. In this study mature leaves of this genotype collected from the same tree in July 2007 and July 2006 were shown to contain respectively 0.59 ± 0.04 and 0.85 ± 0.04 μmol g −1 DW. Other abundant organic substances like arbutine, quinic acid, malic acid, sucrose as well as chlorogenic acid and other quinic acid adducts, might also behave as osmotically active substances. In addition to arbutine, its derivative hydroquinone, chlorogenic acid and structurally related substances might be involved in protective functions against secondary oxidative stresses induced by abiotic and biotic stresses encountered during the growing season.

PLANT WINNERS AND LOSERS DURING GRASSLAND N-EUTROPHICATION DIFFER IN BIOMASS ALLOCATION AND MYCORRHIZAS

Human activities release tremendous amounts of nitrogenous compounds into the atmosphere. Wet and dry deposition distributes this airborne nitrogen (N) on otherwise pristine ecosystems. This eutrophication process significantly alters the species composition of native grasslands; generally a few nitrophilic plant species become dominant while many other species disappear. The functional equilibrium model predicts that, compared to species that decline in response to N enrichment, nitrophilic grass species should respond to N enrichment with greater biomass allocation aboveground and reduced allocation to roots and mycorrhizas. The mycorrhizal feedback hypothesis states that the composition of mycorrhizal fungal communities may influence the composition of plant communities, and it predicts that N enrichment may generate reciprocal shifts in the species composition of mycorrhizal fungi and plants. We tested these hypotheses with experiments that compared biomass allocation and mycorrhizal function of four grass ecotypes (three species), two that gained and two that lost biomass and cover in response to long-term N enrichment experiments at Cedar Creek and Konza Long-Term Ecological Research grasslands. Local grass ecotypes were grown in soil from their respective sites and inoculated with whole-soil inoculum collected from either fertilized (FERT) or unfertilized (UNFERT) plots. Our results strongly support the functional equilibrium model. In both grassland systems the nitrophilic grass species grew taller, allocated more biomass to shoots than to roots, and formed fewer mycorrhizas compared to the grass species that it replaced. Our results did not fully support the hypothesis that N-induced changes in the mycorrhizal fungal community were drivers of the plant community shifts that accompany N eutrophication. The FERT and UNFERT soil inoculum influenced the growth of the grasses differently, but this varied with site and grass ecotype in both expected and unexpected ways suggesting that ambient soil fertility or other factors may be interacting with mycorrhizal feedbacks.

Biochemical, sensorial and genomic profiling of traditional Italian tomato varieties

Fruit flavour of traditional tomato ecotypes differs from that of modern varieties, the latter being often blamed for lack of flavour. To respond to consumer complaints breeders should know the range of genetic variability available in tomato resources, including local ecotypes, for improving flavour. For this purpose, multitrait characterization, including biochemical, sensorial and molecular analyses, was performed on 12 Italian tomato ecotypes that belong to different types (San Marzano, Sorrento, and Vesuvio). The ecotypes showed a significant variation both in glucose and citric acid content. As for amino acid determination, lysine, aspartic acid and serine showed significant variation among the three types analyzed. Sensory analysis clearly evidenced differences among genotypes: the San Marzano ecotypes revealed sensory profiles that differ from the control processing variety in perception of sweetness and sourness, whereas the Sorrento and Vesuvio ecotype profiles were similar to the fresh market control. In particular, Vesuvio genotypes exhibited a good intensity of tomato aroma and sweetness and an intermediate level of acidity. Finally, molecular characterization performed through AFLP markers provided evidence for a very high level of polymorphism: an ecotype-specific AFLP pattern was identified for at least 11 genotypes, thus defining their molecular fingerprints.

Compatible host/mycorrhizal fungus combinations for micropropagated sea oats: II. Field evaluation

Sea oats (Uniola paniculata L.) are the dominant plant in the pioneer coastal dunes of Florida and are widely used for dune restoration. DNA analysis has revealed significant ecotypic variation among Atlantic and Gulf coast populations of sea oats, but little is known about the diversity of the arbuscular mycorrhizal (AM) communities present in the dune systems. In a prior greenhouse study, we evaluated the functional diversity that exists among the AM fungal communities from divergent Florida dunes and selected effective host/AM fungus combinations for further study. The objective of this study was to evaluate the effect of these compatible combinations on the growth of sea oats planted at Anastasia State Recreation Area (AN) on the Atlantic coast and St. George Island State Park (SG) on the Gulf coast. Micropropagated sea oats from each site were inoculated with AM fungal communities also from AN and SG or a microbial filtrate control. The complete factorial of treatment combinations were grown in the greenhouse for 8 weeks and outplanted to the AN and SG field sites. After 1 year, root colonization was evaluated, and after 2 years, root colonization, shoot and root dry masses, and shoot- and root-P contents were determined. Overall, sea oats planted at AN had greater percent root colonization, shoot dry mass, and shoot-P content than those planted at SG. At AN, the local sea oat ecotype responded more to the fungal community from the same site relative to shoot dry mass and shoot-P content. At SG, the local fungal community produced larger plants with greater P content regardless of the origin of the host. We conclude that sea oat productivity is responsive to AM fungal ecotype as well as host ecotype, and fungal origin should therefore be taken into account when planning sea oat plantings on coastal dunes.

Interactions between mountain birch seedlings from differentiated populations in contrasting environments of subarctic Russia

So far very few experiments have accounted for the combined effect of two phenomena co-occurring in stress gradients: local adaptation to stress and the increase in facilitation with increasing stress (predicted by the stress-gradient hypothesis, SGH). Mountain birch (Betula pubescens subsp. czerepanovii) facilitates conspecific seedlings in subarctic high stress sites and is capable of rapid evolutionary adaptation, being therefore a good model species for a study combining local ecotypes and SGH. A within-species experiment was conducted to test SGH in three stress gradients, detect potential local adaptations between low and high stress populations, and assess their effects on seedling-seedling interactions. Although no evidence for local adaptation was detected, high and low stress populations showed some differentiation, possibly explained by decreasing phenotypic plasticity in high stress conditions and/or neutral evolutionary mechanisms. Weak support for SGH was detected. While facilitation was unaffected by seedling origin, low stress populations showed better competitive ability.

Variability of needle structure in Siberian stone pine in provenance plantations

Siberian stone pine (Pinus sibirica Du Tour) is one of the most common trees in Siberia. Its natural range is from the Ural Mountains to the Aldan river and from the Arctic Circle to northern Mongolia. The climate in natural Siberian stone pine sites influences the whole plant organism, particularly its needle structure, and the response to this occurs at specific morphological and anatomical levels. The genotypical and environmental effects on needle structure in different Siberian stone pine ecotypes are very little known. One effective way to examine and to separate genotypical effects from environmental ones is by using a common garden experiment. The purpose is to analyze morphological and anatomical needle variability in Siberian stone pine marginal populations that have been grown in provenance plantations in southern West Siberia, Russia. The needle samples were collected in the provenance plantation located 30 km south of Tomsk (the southeastern West Siberian Plain, southern limit of the taiga zone, optimum site conditions for Siberian stone pine). We investigated the grafts of mother trees taken from natural sites. Four ecotypes were selected for the study. Three ecotypes originated from northern (Urengoy), western (Neviyansk), and eastern (Severobaikalsk) marginal populations. The fourth, the Tomsk ecotype, was a local control. The local Tomsk ecotype grows on a site where natural conditions are worse due to reduction of mean annual temperature and increase of the humid factor northward, humidity reduction eastward and its rise westward. Variability of 10 needle morphological and anatomical characteristics was studied. The northern ecotype had smaller needle length (28%), leaf cross-section area (21%), mesophyll area (29%), mesophyll cell size (27%), and conducting bundle area (16%) but the number of stomata per unit leaf area increased by 16% over the local Tomsk ecotype. The resin canal area, epidermal and hypodermal cell thickness, and stomata size were equal to both the northern and local ecotypes. The leaf cross-section and mesophyll area in the western ecotypes decreased by 20% and 23%, respectively, but stomata size increased by 12%. The needle length, mesophyll cell size, conducting bundle area, resin canal area, the number of stomata per unit leaf area, and epidermal and hypodermal cell thickness did not differ significantly from the same characteristics in the Tomsk ecotype. The leaf cross-section area, mesophyll area, and mesophyll cell size in the eastern ecotype decreased by 22%, 37% and 20% respectively, as compared with the local ecotype. All other studied needle characteristics did not differ from the local ecotype. The common morphological and anatomical parameters did not change from south to north and from west to east (resin canal area and hypodermal cell thickness) and parameters varied in each ecotype. For example, needle length, conducting bundle area, and the number of stomata per unit leaf area changed along latitude but did not change along longitude. Conversely, stomata size and epidermal cell thickness changed along longitude but did not change along latitude. Thus the morphological and anatomical characteristics were specific for each ecotype. The parameter variability of the needle structure is hypothesized to relate to graft geographical provenance that depends on genotype and adaptation properties of mother trees.

Variability of photosynthetic parameters of Pinus sibirica Du Tour needles under changing climatic factors

The air temperature and relative humidity and the intensity of photosynthetically active radiation are the basic ecological factors determining geographical distribution of a species. Wood plant adaptation depends on the intensity of physiological and biochemical processes of plants as a response to changing environmental factors. Investigations to reveal (detect) the variability of modification and genetic components of the photosynthetic parameters in needles of the Siberian cedar (Pinus sibirica Du Tour) mountain ecotypes, distributed in central part of the Altai Mountains, were carried out. Also, the survey was extended to some experiments with these ecotypes introduced to mild climate and flat regions from south-western of Siberia. The length and thickness of needles, the size of chloroplasts, content of the photosynthetic pigments, and the functional activity of chloroplasts at the level of photo system II were the evaluated traits. Growing under mountainous conditions (at about 2000m elevation), the two-year-old needles were shorter and thicker and contained very large in size chloroplasts while the content of chlorophylls and carotinoids was twice lower than that in the local ecotype growing in the lowlands. On the other hand, more green and yellow pigments were found in needles of mountain ecotypes planted in the lowlands compared to the local lowland ectype trees. A decrease in pool of the photosynthetic pigments in the highlands ecotypes is probably due to decreased biosynthesis and increased photo-destruction caused by severe light and temperature conditions. These parameters are likely to be associated with modifications due to intense insolation, low temperature, ozone concentration, UV radiation, and other negative factors that are more pronounced at high elevation. Despite the large pool of accumulated photosynthetic pigments, the functional activity of chloroplasts in the mountain ecotype at the level of photosystem II was lower than that in the local ecotype. Thus, the increased photosynthetic intensity under favorable conditions follows the path of formation of both a larger number of reaction centers and light-harvesting pigments.

Fungitoxicity of lyophilized and spray-dried garlic extracts

Among the compounds discussed for anti-microbial and anti-fungal use allicin (allylthiosulfinate, diallyl disulfide-S-monoxide), an active ingredient of garlic, has attracted considerable attention. The objective of this study is to determine the antifungal activity of a local garlic ecotype (Voghiera) extracts against different pathogens. Primary screening was carried out by the agar plates technique using ethanol garlic extract at four final concentrations against the following organisms: Alternaria alternata, Aspergillus spp., Colletotrichum acutatum, Didymella bryoniae, Fusarium culmorum, Fusarium avenaceum, Fusarium gramineareum, Gliocladium roseum 47, Pythium splendens, Rhizoctonia solani, Sclerotium rolfsii, Stemphylium vesicarium, Trichoderma longibranchiatum, and Botrytis cinerea. Secondary screening was carried out using a lyophilized and a spray-dried preparation at different concentrations against the organisms selected for the high inhibition garlic effect in the primary screening and compared with the commercial fungicides mancozeb and iprodione. The best results were observed for the spray-dried garlic compound that showed a good fungicidal activity at the concentration of 1.5 g/10 mL while lyophilized garlic at the same concentration exhibithed less inhibition activity against the four fungi analyzed in the second screening.

Genetic Diversity in Restoration Materials and the Impacts of Seed Collection in Colorado’s Restoration Plant Production Industry

Abstract The ever increasing demand for native plants and seed for use in restoration and revegetation has created a sizable industry. The large‐scale production and planting of native plants have given rise to a suite of ecological concerns including collection impacts, genetic diversity, and provenance. This study examines the practices and beliefs of 12 restoration plant production companies in Colorado with regard to arising ecological issues and identifies where further research is needed. We found that native seed collection in Colorado was largely unregulated and unmonitored and impacts were unknown. Maintaining genetic diversity in restoration materials is costly and does not have universal support. The use of provenance material (or local ecotypes) was hotly contested with strong and sound arguments on both sides of the issue. Procurement of pure ecotypes was difficult because of the variety of institutions involved in production and complications such as artificial selection and cross‐pollination.

Changes in antioxidants and taste-related compounds content during cold storage of fresh-cut red sweet peppers

Changes in antioxidants (ascorbic acid, phenolic compounds and carotenoids) and in taste-related compounds (sugars and organic acids) content were monitored in fresh-cut red sweet peppers (Capsicum annuum L., local ecotype “Peperone Cornetto di Pontecorvo”) during 9 days of cold storage. Pepper slices were placed in polystyrene trays, wrapped with a polyvinyl chloride film, and stored at 4 °C or at 8 °C; besides, to evaluate the effect of a prestorage hot water treatment, half of the slices were subjected to a dipping treatment in water at 53 °C for 4 min, before packaging and storage. During storage limited changes in O2 and CO2 concentrations were observed within all packages. Storage temperature strongly affected weight loss: at the end of the storage time it was 10% in fruits stored at 4 and 8 °C, respectively. Sugars (glucose and fructose) content showed a significant increase (+11%) only in fruits stored at 8 °C; this change was due to a concentration effect associated to water loss. A higher increase (+23 and +17% in fruits stored at 8 and 4 °C) was observed in organic acids (citric and malic) content. Minimal processing and storage produced only a quite limited degradation of ascorbic acid. Both hydroxycinnamic acid derivatives and flavonoids accumulated in fruits stored at 8 °C (and not heat treated), whereas at 4 °C phenolics accumulation appeared to be partially inhibited. All the main carotenoids (capsanthin, cucurbitaxanthin A, zeaxanthin, β-carotene and β-cryptoxanthin) markedly accumulated in fruits stored at 8 °C (not heat treated), and showed a general decrease at 4 °C. Hot water treatment did seem to affect organic acids metabolism, though it did not promote ascorbic acid degradation. In addition, it inhibited both phenolics and carotenoid accumulation in fruits stored at 8 °C.

Parallel evolution of dwarf ecotypes in the forest tree Eucalyptus globulus

Three small populations of a dwarf ecotype of the forest tree Eucalyptus globulus are found on exposed granite headlands in south-eastern Australia. These populations are separated by at least 100 km. Here, we used 12 nuclear microsatellites and a chloroplast DNA marker to investigate the genetic affinities of the dwarf populations to one another and to their nearest populations of tall E. globulus. Cape Tourville was studied in greater detail to assess the processes enabling the maintenance of distinct ecotypes in close geographical proximity. The three dwarf populations were not related to one another and were more closely related to adjacent tall trees than to one another. At Cape Tourville the dwarf and tall ecotypes were significantly differentiated in microsatellites and in chloroplast DNA. The dwarf and tall populations differed in flowering time and no evidence of pollen dispersal from the more extensive tall to the dwarf population was found. The three dwarf populations have evolved in parallel from the local tall ecotypes. This study shows that small marginal populations of eucalypts are capable of developing reproductive isolation from nearby larger populations through differences in flowering time and/or minor spatial separation, making parapatric speciation possible.

Evidence for Local Ciliate Endemism in an Alpine Anoxic Lake

Despite its long history, biogeography has received relatively little attention within the field of microbial ecology. Consequently, a fierce debate rages whether protists inhabit restricted geographic areas (endemism hypothesis) or are globally dispersed (ubiquitous dispersal hypothesis). The data presented in this article support the endemism hypothesis. We succeeded in isolating an oligohymenophorean ciliate from a microbial mat in a meromictic anoxic alpine lake (Alatsee) in Germany. The ciliary pattern and the morphometry of this isolate are remarkably similar to Urocentrum turbo (Mueller, 1786) Nitzsch, 1827. However, the organism does not possess trichocysts, a conspicuous and characteristic feature of U. turbo. Instead, the U. turbo-like isolate from lake Alatsee displays merely trichocyst anlagen ("ghosts") in the cytoplasm that are only visible after protargol impregnation and which become never attached to the cell's cortex. Despite the distinctness of this difference, such a morphospecies has not been described from any other environment. Thus, we suggest that the U. turbo-like isolate from lake Alatsee is a local endemic ecotype, although the sequences of the 18S rRNA, ITS1, 5.8S rRNA, and ITS2 genes are nearly identical to those of U. turbo (Mueller, 1786) Nitzsch, 1827. This indicates that neither 18S rDNA nor ITS1, ITS2, and 5.8S rDNA sequences are reliable means to conclusively resolve different morphospecies or ecotypes of ciliates. As a consequence, we argue that protist species richness can only be reliably accounted for by considering both molecular and morphological data.

Towards Greener Stormwater Management

Abstract In the past decade, the focus of stormwater management has moved from a more traditional paradigm to a variety of more ecologically sensitive, “green” stormwater solutions. Because of an increased ecological focus, stormwater management techniques are no longer selected from a one-size-fits-all toolkit, making adjustments only for storage and transport volumes to account for local differences in rainfall and contributing area. Instead, the current generation of stormwater managers has a wealth of options from which to choose, leading to solutions that need to be specifically formulated for or adapted to local soils, ecotypes, topography, and meteorology. Furthermore, there has also been a move away from the more traditional engineered systems toward an increased multi-disciplinary approach. As a result, stormwater can no longer be managed as an afterthought to development. Instead, stormwater managers and developers need to be communicating throughout the design process. This combination of an ev...

Effets d’un stress hydrique sur les rendements de deux écotypes locaux de mil (Pennisetum glaucum (L.) R. Br.)

Deficit or regulated deficit irrigation is one way of saving water in regions with limited water resources, without negatively affecting crop yields. The effectiveness of this approach can be assessed using coefficients of yield responses to water supply. For the purpose of this study, this parameter was monitored using 1g of salt/L of irrigation water, under 3 levels of water supply (40, 70 and 100% ETM) applied to 2 local ecotypes of millet available in Tunisia (Djerba, DJ; and Kairouan, KN). The results showed that the maximum crop water consumptions (ETM) were 497mm and 562mm for ecotypes DJ and KN, respectively. Under the 70% ETM and 40% ETM irrigation regime, crop water consumption was significantly reduced, by 25 and 58% respectively for ecotype DJ, and by 29 and 57% respectively for ecotype KN. The yield reduction obtained was slightly less than that observed under unrestricted water conditions, and with no significant difference between the 2 ecotypes. As a consequence, a yield response factor (Ky) close to 1 was adjusted. This shows the capability of the two millet ecotypes to cope with water scarcity and confirms the importance of pear millet in regions with limited water resources.

Differences in resistance to Salmonella enterica serovar Gallinarum infection among indigenous local chicken ecotypes in Tanzania

A study was conducted to evaluate the disease resistance potential in 105 chickens of six indigenous local chicken ecotypes in Tanzania by orally challenging 1-week-old chicks with 2.5 x 10(8) colony-forming units of virulent S. Gallinarum. For 14 days post infection, clinical signs, necropsy findings, antibody titres, packed cell volume, leukocyte population count, and viable bacterial cell counts in the liver and spleen were recorded. Clinical signs were recorded daily but other parameters were recorded on the day of infection, then on days 3, 6, 10 and 14 after infection. Clinical signs of fowl typhoid were evident in chickens from day 3 post infection and disappeared by day 9 post infection. Pathological lesions on sacrificed birds included enlargement of the liver and spleen with foci of necrosis on the liver, spleen and myocardium. The mean viable bacterial cell counts in the liver and spleen varied between ecotypes, although the differences were not statistically significant. There were significant differences in the leukocyte population in the peripheral blood, with one ecotype (Morogoro-medium) showing a consistent and significantly higher heterophil count compared with other ecotypes. It was concluded that there is a selectable resistance potential to S. Gallinarum among the local chicken ecotypes in Tanzania that may be attributable to non-specific host immune responses. Further studies are suggested.

The ‘Design’ of Mediterranean Landscapes: A Millennial Story of Humans and Ecological Systems during the Historic Period

What makes the structure and dynamics of coupled natural and human systems difficult to interpret in the Mediterranean is the extreme diversity in space and time of both environments and human societies. The succession of civilizations that waxed and waned in the Mediterranean Basin over several millennia has had great impacts on biota and ecosystems everywhere in the basin. A complex ‘coevolution’ has been claimed to shape the interactions between ecosystem components and human societies. Two opposing schools of thought traditionally have considered the consequences of human pressures on Mediterranean ecosystems. The ‘Ruined Landscape’ or ‘Lost Eden theory’ argues that human action resulted in a cumulative degradation and desertification of Mediterranean landscapes. The second school argues that humans actually contributed to keeping Mediterranean landscapes diverse since the last glacial episode. With this debate in mind, I show the following: (1) One cannot understand the components and dynamics of current biodiversity in the Mediterranean without taking into account the history of human-induced changes; (2) The various systems of land use and resource management that provided a framework for the blossoming of Mediterranean civilizations also had profound consequences on the distribution and dynamics of species, communities, and landscapes; (3) The processes of domestication of plant and animal species, which first occurred in the eastern Mediterranean area some 10,000 years ago, contributed to the increase of certain components of biodiversity at several spatial scales. Positive and negative feedback cycles between cultural practices and natural systems at the local and regional levels have kept ecosystems robust and resilient; (4) Assuming that human action can, to a certain extent, be considered a large-scale surrogate for natural sources of ecosystem disturbance, such patterns give support to the diversity-disturbance hypothesis—specifically, intermediate levels of disturbance have promoted biological diversity; (5) Intraspecific adaptive variation increased as a result of human-induced habitat changes over millennia, resulting in bursts of differentiation during the later Holocene of local ecotypes and gene pools of domesticated and wild plant and animal species, with region-specific characters fitting them to local climate and environmental conditions. High intraspecific adaptive variation also arose from earlier natural processes of the Pleistocene, mainly from a combination of periodic refugia formation and climate dynamics. During the Holocene, the main sources of disturbance came increasingly from humans, specifically from the coupled cultural and natural modifications of community and landscape structure. It is concluded that a high degree of resilience of Mediterranean ecosystems resulted in a dynamic coexistence of human and natural living systems, which in some cases provided stability, while fostering diversity and productivity (Blondel and Aronson, 1999). The word “design” used in the title and elsewhere in this paper metaphorically indicates that the long-lasting influence of human impacts resulted in an unintentional shaping of individual components of landscapes.

Abiotic ecotypes in south-central Spanish rivers: Reference conditions and pollution

Physico-chemical water quality in five of Spain's main rivers was assessed during the years 2001–2003. A previous physiographical river typology was carried out by applying System B of the Water Framework Directive (2000/60/CE) which distinguished four main river ecotypes: calcareous headwaters, siliceous rivers, plain rivers, and large rivers. The physiographical classification into river ecotypes also corresponded to distinct hydrochemical types. Reference values of ammonium, nitrate and phosphate fitted for local river ecotypes surpassed only slightly the natural and background levels established by the European Environmental Agency (EEA, 2003). Half of the sampled sites were above the limits established as reference conditions. Additionally, concentrations of ammonium, nitrite, nitrate, and phosphate increased when more percentage of land was dedicated to agriculture and less to forest land.

White clover cultivars developed for temperate regions of South America

White clover is an important forage legume in temperate areas of South America but the common cultivars used are winter-active, profuse flowering types and only persist for 2-3 years due to frequent moisture stress and hot summer conditions. A breeding programme was initiated to develop new types for intensive dairy and extensive cattle grazed pastures. Wide scale screening and crossing of germplasm from international and local sources revealed the potential of Ladino and ladino x local cultivar material for use in intensive pastures with good soils and grazing management. Improved persistence was a major objective for the extensive pastures and ecotype material collected from local farms together with crosses involving ladino and SE USA ecotypes were the best combinations. Experimental selections were developed for the two target environments and evaluated in 'scope' trials at three contrasting sites to determine herbage production and persistence potential. A ladino x local cultivar selection with large leaves, high herbage yields, extended winter to summer growth and ability to persist for at least 3 years was released as the cultivar 'Goliath' for intensive dairy-type pastures. A local ecotype selection with medium leaf size, slower establishment but high stolon density aiding persistence, and high seed yields was released as the cultivar 'Aquiles' for use in extensive pastures

Internal quality of fresh and cold stored celery petioles described by sensory profile, chemical and instrumental measurements

Internal quality of fresh and cold stored celery petioles of four different accessions (two green cultivars, one yellow cultivar and one yellow local ecotype) was characterised by descriptive analysis of sensory properties of aspect, flavour and texture, chemical determinations (organic acids, sugars, dietary fibre, flavonoids, carotenoids) and instrumental measurements of texture (stiffness, fracture toughness, maximum shear force). In the growing conditions as adopted in the experiment, different genotypes produced petioles with quite similar and low levels of dry matter, but with significant differences in some texture (flexibility, fracturability, hardness, crunchiness and fibrousness), flavour (odour and total flavour) and taste (saltiness and bitterness) attributes. After fortnight of cold storage (2 °C, 75–85% RH) differences between genotypes were still perceived in some texture attributes, particularly flexibility, fracturability and hardness. On the other hand, significant differences were no longer observed in total flavour, whereas lowered differences were still perceived in odour. Green type cultivars distinguished for higher fibrousness, bitter taste and harsh after effect. Sweetness was not linearly correlated to total and individual sugar contents, whereas organic acids content was probably too low to cause perceivable sourness; moreover, the sensory perception of fibrousness during chewing seemed to be related to other constituents in addition to fibre. Finally the low contents of flavones (apigenin 0.76–3.11 mg/kg and luteolin 0.50–1.74 mg/kg) and carotenoids (lutein 0.60–1.58 mg/kg and β-carotene 0.20–0.71 mg/kg) in all genotypes suggested a poor relevance of celery petioles devoid of leaves as dietary sources of these bioactive compounds.

Onions in West Africa: state of research and future prospects

AbstractThe evaluation of local ecotypes has promoted their exploitation in breeding schemes and the creation of lines resistant to thrips and to pink root rot. Promotion of the cultivar Violet de Galmi from Niger has helped to improve onion yields throughout the region. Three distinct groups of ecotypes of onions can be characterized by their yield, their earliness and their storage performance. Improved local varieties have been brought into commercial use. Several onion lines are being used for breeding varieties resistant to bolting and with good storage capability. Copyright © 2005 John Wiley &amp; Sons, Ltd