Level of trace elements in Pteridophytes growing on serpentine and metalliferous soils     

Laura Cornara  Enrica Roccotiello  Vincenzo Minganti  Giuliana Drava  Rodolfo De Pellegrini  Mauro Giorgio Mariotti 《植物养料与土壤学杂志》2007,170(6):781-787

A screening of Pteridophytes growing on serpentine and metalliferous soils in Northern Italy was carried out to assess the ability of these plants to tolerate or accumulate trace elements of toxicological interest. Few data are available on metal tolerance/accumulation of terrestrial ferns growing in the Mediterranean region, and several species presented here have never been investigated for this purpose. The trace‐element composition (As, Cd, Cr, Cu, Fe, Ni, Pb, Zn) and P content of aerial parts of plants (12 fern and 2 horsetail species) and of their associated soils were measured. An analysis of the relationship between element concentrations in soil and in shoot revealed a significant correlation only for Zn (p < 0.05). Hierarchical cluster analysis based on element concentrations in plant aerial parts showed two outliers, viz. Equisetum ramosissimum Desf., showing the highest levels of Cr, Fe, Cu, Ni, and As, and Nephrolepis cordifolia C. Presl., showing the highest Pb value. The bioaccumulation factor exceeded 1 only for Cd in two species, Athyrium filix‐femina and Dryopteris filix‐mas. However, also in these cases the corresponding values of the metal in the shoots were below the thresholds for hyperaccumulators. The examined Pteridophytes seem to have developed their adaptation prevalently through mechanisms of tolerance based on metal exclusion. None of these plant species seem suitable for phytoextraction, but N. cordifolia, Pteridium aquilinum ssp. aquilinum, and E. ramosissimum have potential to be used for stabilization and restoration of soils rich in heavy metals.  相似文献   

Biased seed rain in forest edges: Evidence from the Brazilian Atlantic forest     

Felipe Pimentel Lopes de Melo  Rodolfo Dirzo 《Biological conservation》2006,132(1):50-60

In this paper, we test the hypothesis that seed rain in forest edges differs from that in forest interior in terms of seed abundance, species richness, seed size, dispersal mode, and manipulation by vertebrates. The study was carried out in the Coimbra forest (3500 ha), the largest fragment currently found in the Atlantic forest of northeast Brazil. We assessed seed rain during a 1-year period by using a 1500-m long transect (with 100 sampling units) for each habitat. Seeds were categorized according to size, dispersal mode, and vertebrate manipulation. A total of 76,207 seeds belonging to 146 species were collected during the whole study and in average edge received more seeds and species per unit of area during particular periods of time. However, the analysis of all seeds and species recorded in both habitats during the 1-year period revealed that forest interior received a significant higher percentage of medium, large and very large seeds (21.8%) and species (82.6%) in comparison to edge (13.5% of seeds and 57.5% of species). The contribution of large and very large seed species dispersed by vertebrates was also lower in the edge forest as it represented 13.04% of all vertebrate-dispersed species recorded in this habitat vs. 31.5 % in the forest interior. Finally, seeds handled by vertebrates accounted for 5.9% of all seeds in forest edge, and reached 11% in the forest interior. The biased seed rain documented in the Coimbra forest raises the possibility that the creation of forest edges may alter some attributes of seed rain, particularly its content of large-seeded plants and of those dispersed by vertebrates.  相似文献   

Blue-light-activated histidine kinases: two-component sensors in bacteria     

Swartz TE  Tseng TS  Frederickson MA  Paris G  Comerci DJ  Rajashekara G  Kim JG  Mudgett MB  Splitter GA  Ugalde RA  Goldbaum FA  Briggs WR  Bogomolni RA 《Science (New York, N.Y.)》2007,317(5841):1090-1093

Histidine kinases, used for environmental sensing by bacterial two-component systems, are involved in regulation of bacterial gene expression, chemotaxis, phototaxis, and virulence. Flavin-containing domains function as light-sensory modules in plant and algal phototropins and in fungal blue-light receptors. We have discovered that the prokaryotes Brucella melitensis, Brucella abortus, Erythrobacter litoralis, and Pseudomonas syringae contain light-activated histidine kinases that bind a flavin chromophore and undergo photochemistry indicative of cysteinyl-flavin adduct formation. Infection of macrophages by B. abortus was stimulated by light in the wild type but was limited in photochemically inactive and null mutants, indicating that the flavin-containing histidine kinase functions as a photoreceptor regulating B. abortus virulence.  相似文献   

Membrane-assisted processing of xylooligosaccharide-containing liquors     

Vegas R  Luque S  Alvarez JR  Alonso JL  Domínguez H  Parajó JC 《Journal of agricultural and food chemistry》2006,54(15):5430-5436

Liquors from rice husk autohydrolyis, containing xylooligosaccharides, other saccharides, and nonsaccharide compounds, were subjected to two selected processing schemes to increase the proportion of substituted xylooligosaccharides in refined liquors. Nanofiltration through a ceramic membrane with a molecular mass cutoff of 1000 Da allowed simultaneous concentration and purification; this latter derived from the preferential removal of monosaccharides and nonsaccharide compounds. When liquors were nanofiltered to achieve a volume reduction factor of 5 operating at a transmembrane pressure of 14 bar, 58.6% of the nonsaccharide components and 20.9-46.9% of monosaccharides were kept in retentate, in comparison with 92% of xylooligosaccharides and glucooligosaccharides. When nanofiltered liquors were subjected to double ion-exchange processing, a final product with a nonsaccharide content near 9 kg/100 kg of nonvolatile components was obtained at a yield of 10.90 kg/100 kg oven dry rice husks. Alternatively, when nanofiltered liquors were subjected to ethyl acetate extraction and further double ion-exchange processing, a purified product with a nonsaccharide content of 5.66 kg/100 kg of nonvolatile components was obtained at a yield of 9.94 kg/100 kg oven dry rice husks. The nonsaccharide components remaining in the final concentrate were mainly made up of phenolic and nitrogen-containing compounds.  相似文献   

Healing ability and diameter growth of lime-trees (<Emphasis Type="Italic">Tilia begonifolia</Emphasis> Stev.) following logging wounds     

Farzam Tavankar  Angela Lo Monaco  Rodolfo Picchio  Rachele Venanzi  Mehrdad Nikooy 《European Journal of Forest Research》2018,137(1):45-55

Lime-trees (Tilia begonifolia Stev.) have countless ecological and economical values in the northern forests of Iran. Bole wounds on residual trees are commonly caused by logging. The healing ability of bole wounds and the effect of bole wounds on diameter growth in lime-trees were assessed in a natural mixed uneven-age stand. The susceptibility to decay in relation to the wound severity was also evaluated. Condition and location of lime-trees before and after selective logging were determined through systematic plot sampling. The position of each lime-tree was identified on a topographical map using the global positioning system. After 10 years from wound occurrence, tree and wound characteristics were also re-measured. Overall, 68 stems (9.7 stem ha^?1) of lime-trees were found in the sampled area, 25 stems (36.8%) were damaged in the form of bole wound, and 43 stems (63.2%) were undamaged. Statistical differences between wounded or non-wounded lime-trees in terms of diameter and height were not found. Most of the wounds occurred at the height of < 1 m; the average wound size was 370.5 cm². Wound severity was related to wound size and wound position. Wound width healing rate was 6.2 mm year^?1. The wound shape was found to be a healing factor as the healing rate by width was higher than that by length. Healed wounds were only 12, 60% of bole wounds resulted in decay. Diameter growth of wounded trees was 43.5% lower than undamaged trees. The average annual diameter growth decreased by increasing wound severity. The results indicated the lime-tree is a very sensitive species to damage caused by logging (bole wound). Single-tree selection cutting needs more careful logging operations to reduce damage on residual lime-trees in order to safeguard this species, valuable in ecologic and economic terms.  相似文献   

First evidence of resistance to pyrethroid insecticides in Italian Aedes albopictus populations 26 years after invasion          下载免费PDF全文

Verena Pichler  Romeo Bellini  Rodolfo Veronesi  Daniele Arnoldi  Annapaola Rizzoli  Riccardo Paolo Lia  Domenico Otranto  Fabrizio Montarsi  Sara Carlin  Marco Ballardini  Elisa Antognini  Marco Salvemini  Emanuele Brianti  Gabriella Gaglio  Mattia Manica  Pietro Cobre  Paola Serini  Enkelejda Velo  John Vontas  Ilias Kioulos  Joao Pinto  Alessandra della Torre  Beniamino Caputo 《Pest management science》2018,74(6):1319-1327

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Effects of Leucaena biomass application in conjunction with fertilizers on cassava and taro yields in the Philippines     

Rodolfo G. Escalada  Berta C. Ratilla 《Agroforestry Systems》1998,41(3):251-266

With the soaring cost and scarcity at times of inorganic fertilizers in the country, there is a need to find alternatives to inorganic fertilizers by making use of indigenous materials such as leaves of leguminous plants, mudpress, and so enhance growth and development of crops. Application of ‘ipil-ipil’ (Leucaena leucocephala) green manure supplemented with inorganic P and K caused vigorous growth of cassava (Manihot esculenta). Application of ipil-ipil biomass at the rate of 7.23 t ha−1 resulted in high yield and better values of yield components of cassava. However, due to high expenses incurred in hauling, transport and cost of the green manure materials, their use is likely to be more economical and feasible only if ipil-ipil is readily available in the farm. With taro (Colocasia esculenta), combined application of ipil-ipil green manure and inorganic P and K promoted vigorous stand and higher yield of the crop. Significantly larger corms were formed resulting in higher total corm yields and marketability than the control (untreated) and those treated only with 60–39.6–74.7 kg ha−1 N, P, and K from inorganic fertilizer. Increasing the rate of inorganic N applied to plants (90–36.9–74.7 kg ha−1 N, P, K) during a third cropping, gave comparable yield to treatment involving 7.23 t ha−1 ipil-ipil supplemented with inorganic P and K. Despite the relatively higher gross income obtained from organic and inorganic treatment combinations, slightly lower net income was obtained compared with inorganic fertilizer-applied plants due to higher production expenses incurred with the former treatments. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

Reproductive cycle of the sea cucumber <Emphasis Type="Italic">Holothuria floridana</Emphasis> in the littorals of Campeche,Mexico     

Julia Ramos-Miranda  Rodolfo del Río-Rodríguez  Domingo Flores-Hernández  Ramón Isaac Rojas-González  Mónica Gómez-Solano  Ana Delia Cu-Escamilla  Francisco Gómez-Criollo  Atahualpa Sosa-López  Yassir Eden Torres-Rojas  Paloma Juárez-Camargo 《Fisheries Science》2017,83(5):699-714

The reproduction of Holothuria floridana in Campeche bay, southern Gulf of Mexico, was investigated over a period of 12 months by macroscopic and histological examination of the gonad and gametogenesis. A total of 1938 specimens were collected. Their body gutted weight and body gutted length ranged from 15 to 225 g and 5 to 21 cm, respectively. Percentage of the gonad weight to the gutted body weight (gonad index, GI) increased steadily from December to April, rapidly declined in May, and remained low during the following months. GI displayed a negative correlation with temperature of the habitat and no correlation with salinity. The gonad maturity scale with five stages was developed from macroscopic and microscopic observations; I, recovery; II, growing; III, early mature; IV, mature and V, spent. Stages III to V were observed all around the year, suggesting that this species displays continuous reproduction with two peaks of spawning events; from March to April and in September. The presence of viscera regurgitated individuals caused high variability in GI. The sex-ratio varied from 1:1 (December 2013 to June 2014), to 1.37:1 (November 2013); we suggest that this may be the consequence of unintentional selective fishing. The body length and body weight at the first maturity were calculated to be 13.4 cm and 87.0 g, respectively. For resource management it will be necessary to address some reference points like harvest season and avoidance of catches shorter than length at first maturity.  相似文献   

Heritability estimates and predictive ability for pig meat quality traits using identity-by-state and identity-by-descent relationships in an F2 population     

Belcy Karine Angarita Barajas  Rodolfo J. C. Cantet  Juan P. Steibel  Matias F. Schrauf  Natalia S. Forneris 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2023,140(1):13-27

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