Genetic control of surface curvature     

Nath U  Crawford BC  Carpenter R  Coen E 《Science (New York, N.Y.)》2003,299(5611):1404-1407

Although curvature of biological surfaces has been considered from mathematical and biophysical perspectives, its molecular and developmental basis is unclear. We have studied the cin mutant of Antirrhinum, which has crinkly rather than flat leaves. Leaves of cin display excess growth in marginal regions, resulting in a gradual introduction of negative curvature during development. This reflects a change in the shape and the progression of a cell-cycle arrest front moving from the leaf tip toward the base. CIN encodes a TCP protein and is expressed downstream of the arrest front. We propose that CIN promotes zero curvature (flatness) by making cells more sensitive to an arrest signal, particularly in marginal regions.  相似文献   

Shrub biomass estimation in the semiarid Chaco forest: a contribution to the quantification of an underrated carbon stock   总被引：1，自引：0，他引：1  

Georgina Conti  Lucas Enrico  Fernando Casanoves  Sandra Díaz 《Annals of Forest Science》2013,70(5):515-524

Context

The quantification of biomass of woody plants is at the basis of calculations of forest biomass and carbon stocks. Although there are well-developed allometric models for trees, they do not apply well to shrubs, and shrub-specific allometric models are scarce. There is therefore a need for a standardized methodology to quantify biomass and carbon stocks in open forests and woodlands.

Aims

To develop species-specific biomass estimation models for common shrubs, as well as a multispecies shrub model, for the subtropical semiarid Chaco forest of central Argentina.

Methods

Eight shrub species (Acacia aroma, Acacia gilliesii, Aloysia gratissima, Capparis atamisquea, Celtis ehrenbergiana, Larrea divaricata, Mimozyganthus carinatus, and Moya spinosa) were selected, and, on average, 30 individuals per species were harvested. Their total individual dry biomass was related with morphometric variables using regression analysis.

Results

Crown area as well as crown-shaped variables proved to be the variables with the best performance for both species-specific and multispecies shrub models. These allometric variables are thus recommended for standardized shrub biomass assessments.

Conclusion

By accounting for the shrub component of the vegetation, our models provide a way to improve the quantification of biomass and carbon in semiarid open forest and woodlands.  相似文献   

Tree-ring Δ13C reveals the impact of past forest management on water-use efficiency in a Mediterranean oak coppice in Tuscany (Italy)     

Giovanni Di Matteo  Paolo De Angelis  Enrico Brugnoli  Paolo Cherubini  Giuseppe Scarascia-Mugnozza 《Annals of Forest Science》2010,67(5):510-510

? The effects of thinning and heavy stand density reduction was investigated in Turkey oak (Quercus cerris L.) forests of central Italy, to evaluate the physiological responses and the growth status of trees that survived a past coppice cut and thinning to convert the stand to high-forest.

? The working hypothesis was that a strong decrease in stand density would cause a decreasing in canopy-intrinsic water-use efficiency (measured as the ratio of CO₂ assimilation to stomatal conductance, A/g), thus an increase in tree-ring carbon isotopic discrimination (Δ¹³C).

? The tree-ring Δ¹³C of the remaining trees (“survivors”) was found to have significantly (P < 0.05) raised between year two and year seven since the coppice stand was thinned (high-forest conversion thinnings). This effect was mostly caused by a large decrease in tree-rings Δ¹³C at control site which was characterized by high density and competition by trees. An increase in survivors tree-rings Δ¹³C probably indicates an improved water availability, possibly induced by a decrease in competition and in stand density or a decrease in the precipitation intercepted by the canopy (i.e., a stronger increase in g over A since a decrease in A is highly unlikely). A change in foliar nitrogen, foliar Δ¹³C and content in chlorophylls was also recorded seven years after thinning.

? Thinnings carried out to convert old abandoned coppices into high-forest stands induce short-term stimulation of Turkey oak growth by increasing light and water availability. We were able to make a detailed reconstruction of the impact of past silvicultural treatment on the stand using a tree-ring wood Δ¹³C time-series.

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Assessment of the impact of forest harvesting operations on the physical parameters and microbiological components on a Mediterranean sandy soil in an Italian stone pine stand     

Martina Cambi  Donatella Paffetti  Cristina Vettori  Rodolfo Picchio  Rachele Venanzi  Enrico Marchi 《European Journal of Forest Research》2017,136(2):205-215

Forest harvesting operations may have a significant impact on soil physical properties by reducing its porosity and organic functions. Soil variations, in particular bulk density and total porosity, caused by external perturbations as soil becomes compacted due to machinery passes, can lead to changes in biogeochemical cycles that have consequences on soil ecosystems. This study investigated how the impact of forest operations and the elapsed time from harvest can influence: (1) the physical–chemical characteristics of soil and (2) the nitrogen-fixing and nitrifying microbial communities. The study area is located inside the Regional Park of Migliarino, San Rossore, Massaciuccoli (Pisa, Italy). In the study area, the soil has been classified as recent sands with sandy loam texture and slightly calcareous (USDA Soil Taxonomy classification). Soil samples were collected in patchy cut areas (strip cut) of Pinus pinea stand that was harvested in two steps: half area in 2006 and the rest in 2011. Soil samples were collected also in a control area (not harvested) with similar stand and soil characteristics. Statistical analysis was preceded by a test of normality (Kolmogorov–Smirnov test) and a variance homogeneity test (Levene’s test). Considering the dependence of the variables studied (physical and chemical soil characteristics), a MANOVA test and a post hoc Tukey HSD test were applied to determine statistical difference among the three treatments: harvested 2006, harvested 2011 and not harvested. The results did not indicate significant variations to the parameters of shear and penetration resistance, though soil bulk density and total porosity were significantly altered in the short period since forestry operations occurred. These physical changes induced qualitative (presence/absence and number of species) and quantitative (abundance and spatial evenness of the species) variations in the nitrogen-fixing and nitrifying microbial communities.  相似文献   

Anti-nutrient analysis of 30 Bambara groundnut (Vigna subterranea) accessions in South Africa     

Amara Evangeline Unigwe  Enrico Doria  Patrick Adebola  Abe. S Gerrano  Michael Pillay 《Journal of Crop Improvement》2018,32(2):208-224

Bambara groundnut is a leguminous crop that originated in West Africa. It is a drought-tolerant crop and has the potential to provide improved food and nutritional security in the dry areas of Africa. However, the plant contains anti-nutritional factors that affect its food value chain. The objective of this study was to assess the content of four major anti-nutritional factors in 30 bambara groundnut accessions in South Africa. The seeds of the bambara groundnut landraces were ground to make a fine powder and assessed for condensed tannins (CTs), phytic acid phosphate (PAP), polyphenol, and trypsin inhibitor content. Each assay was done in triplicate. The content of the four anti-nutritional compounds varied widely among the bambara groundnut accessions. The mean values for CTs ranged between 0.2 and 6.2 mg/g of prodephinidin equivalent, whereas that of the PAP was between 1.4 and 4.9 mg/g. A low mean polyphenol content of 0.4 mg/g of GA (gallic acid) equivalent was observed among the accessions. The level of trypsin inhibitor ranged from 5.3 to 73.4 TI/mg. With the exception of CTs and trypsin inhibitor, no significant correlation was observed among the four anti-nutritional factors assessed in this study. Generally, higher levels of anti-nutrients were observed in this study compared with certain studies reported earlier.  相似文献   

COMPUTED TOMOGRAPHIC FEATURES OF INCISOR PSEUDO‐ODONTOMAS IN PRAIRIE DOGS (CYNOMYS LUDOVICIANUS)          下载免费PDF全文

Igor Pelizzone  Francesco Di Ianni  Antonella Volta  Giacomo Gnudi  Sabrina Manfredi  Mara Bertocchi  Enrico Parmigiani 《Veterinary radiology & ultrasound》2017,58(3):273-283

Maxillary incisor pseudo‐odontomas are common in pet prairie dogs and can cause progressive respiratory obstruction, while mandibular pseudo‐odontomas are rarely clinically significant. The aim of this retrospective cross‐sectional study was to describe CT features of maxillary and mandibular incisor pseudo‐odontomas vs. normal incisors in a group of pet prairie dogs. All pet prairie dogs with head CT scans acquired during the period of 2013–2015 were included. A veterinary radiologist who was aware of final diagnosis reviewed CT scans and recorded qualitative features of affected and normal incisors. Mean density values for the pulp cavity and palatal and buccal dentin were also recorded. A total of 16 prairie dogs were sampled (12 normal maxillary incisors, 20 confirmed maxillary incisor pseudo‐odontomas, 20 normal mandibular incisors, 12 presumed mandibular incisor pseudo‐odontomas). Maxillary incisors with confirmed pseudo‐odontomas had a significantly hyperattenuating pulp and dentin in the reserve crown and apical zone, when compared to normal maxillary incisors. Pseudo‐odontomas appeared as enlargements of the apical zone with a globular/multilobular hyperattenuating mass formation haphazardly arranged, encroaching on midline and growing caudally and ventrally. Presumed mandibular incisor pseudo‐odontomas had similar CT characteristics. In 60% of prairie dogs with maxillary incisor pseudo‐odontomas, the hard palate was deformed and the mass bulged into the oral cavity causing loss of the palatine bone. The common nasal meatus was partially or totally obliterated in 81.8% of prairie dogs with maxillary pseudo‐odontomas. Findings supported the use of CT for characterizing extent of involvement and surgical planning in prairie dogs with pseudo‐odontomas.  相似文献   

Modelling beluga habitat use and baseline exposure to shipping traffic to design effective protection against prospective industrialization in the Canadian Arctic          下载免费PDF全文

Enrico Pirotta  Leslie New  Marianne Marcoux 《水产资源保护:海洋与淡水生态系统》2018,28(3):713-722

Sulphur Isotopes, Trace Elements and Mineral Stability Diagrams of Waters from the Abandoned Fe–Cu Mines of Libiola and Vigonzano (Northern Apennines, Italy)     

Gianni Cortecci  Tiziano Boschetti  Enrico Dinelli  Roberto Cabella 《Water, air, and soil pollution》2008,192(1-4):85-103

The geochemical characteristics of rills draining pyrite-chalcopyrite tailings impoundments and of bordering streams were investigated at the ophiolite-hosted Libiola and Vigonzano abandoned massive sulphide mines, northern Apennines Italy. Water samples were analysed for major and trace chemical composition, hydrogen and oxygen isotope composition, and sulphur isotope composition of aqueous sulphate. Sulphur isotope composition was determined also for some samples of ore sulphides. At Libiola, the newly acquired chemical results on waters corroborate those from previous investigations, thus providing additional support to existing geochemical models in terms of metal distribution, solid phases precipitation, reaction path modelling and mixing reaction paths, and environmental problems. At Vigonzano, the chemical characteristics of waters are similar to those at Libiola. In both localities, solution-secondary phase equilibria estimated using an updated thermodynamic dataset account for mineralogy in the field, including poorly crystalline phases like jurbanite and hydrowoodwardite. The hydrogen and oxygen isotope composition of waters at Libiola and Vigonzano agrees with their meteoric origin. Acid to neutral mine waters do not show any significant isotope shift with respect to the initial water, in spite of the oxidation of even large amounts of pyrite/chalcopyrite ore. The sulphur isotope composition of aqueous sulphate in mine rills at Libiola (δ ³⁴S?=?5.6 to 8.5‰; mean 6.5‰) matches that of massive sulphide ore (δ ³⁴S?=??0.5 to 6.7‰; mean 5.8‰), in keeping with the supergenic origin of the sulphate and related isotope effects in the sulphide oxidation process. Sulphate in mine waters at Vigonzano displays lower δ ³⁴S values in the range 0.6 to 1.5‰. The δ ³⁴S signature of massive ore specimens is within the range reported for most volcanic-hosted massive sulphide deposits, including Cyprus-type deposits.  相似文献   

Assessment of the nutritional values of genetically modified wheat, corn, and tomato crops     

Venneria E  Fanasca S  Monastra G  Finotti E  Ambra R  Azzini E  Durazzo A  Foddai MS  Maiani G 《Journal of agricultural and food chemistry》2008,56(19):9206-9214

The genetic modification in fruit and vegetables could lead to changes in metabolic pathways and, therefore, to the variation of the molecular pattern, with particular attention to antioxidant compounds not well-described in the literature. The aim of the present study was to compare the quality composition of transgenic wheat ( Triticum durum L.), corn ( Zea mays L.), and tomato ( Lycopersicum esculentum Mill.) to the nontransgenic control with a similar genetic background. In the first experiment, Ofanto wheat cultivar containing the tobacco rab1 gene and nontransgenic Ofanto were used. The second experiment compared two transgenic lines of corn containing Bacillus thuringiensis "Cry toxin" gene (PR33P67 and Pegaso Bt) to their nontransgenic forms. The third experiment was conducted on transgenic tomato ( Lycopersicum esculentum Mill.) containing the Agrobacterium rhizogenes rolD gene and its nontransgenic control (cv. Tondino). Conventional and genetically modified crops were compared in terms of fatty acids content, unsaponifiable fraction of antioxidants, total phenols, polyphenols, carotenoids, vitamin C, total antioxidant activity, and mineral composition. No significant differences were observed for qualitative traits analyzed in wheat and corn samples. In tomato samples, the total antioxidant activity (TAA), measured by FRAP assay, and the naringenin content showed a lower value in genetically modified organism (GMO) samples (0.35 mmol of Fe (2+) 100 g (-1) and 2.82 mg 100 g (-1), respectively), in comparison to its nontransgenic control (0.41 mmol of Fe (2+) 100 g (-1) and 4.17 mg 100 g (-1), respectively). On the basis of the principle of substantial equivalence, as articulated by the World Health Organization, the Organization for Economic Cooperation and Development, and the United Nations Food and Agriculture Organization, these data support the conclusion that GM events are nutritionally similar to conventional varieties of wheat, corn, and tomato on the market today.  相似文献   

Calcium chloride washing of calcareous sediment from a freshwater canal: effect on the removal of potentially toxic elements and water aggregate stability     

Buscaroli  Enrico  Sciubba  Luigi  Falsone  Gloria  Cavani  Luciano  Brecchia  Matteo  Argese  Emanuele  Marzadori  Claudio  Pourrut  Bertrand  Braschi  Ilaria 《Journal of Soils and Sediments》2019,19(7):3098-3107

Journal of Soils and Sediments - Canal dredging and shaping produce considerable amounts of sediments whose reuse on- and off-site depends on their pollution level. This study explores the...  相似文献