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101.
Raphael De Leão Serafini Evoy Zaniboni‐Filho Bernardo Baldisserotto 《Journal of the World Aquaculture Society》2009,40(5):695-701
The aim of this study was to assess the mean lethal concentration (LC50) of dissolved oxygen in high ammonia concentration and also the LC50 of ammonia under hypoxic conditions for juveniles of dourado, Salminus brasiliensis. In the first experiment, the non‐ionized ammonia (NH3) concentrations were: 0.026, 0.447, 0.612, 0.909, and 1.334 mg/L, and the dissolved oxygen concentration was maintained at approximately 1.65 mg/L. In the second experiment, the dissolved oxygen concentrations were: 1.64, 1.99, 3.33, 5.10, and 7.77 mg/L, and the non‐ionized ammonia concentration was kept at approximately 0.927 mg/L. The mean lethal concentrations of non‐ionized ammonia varied from 0.584 to 0.577 mg/L, indicating that LC50 values were almost unaffected by exposure time. The estimated LC50 of dissolved oxygen varied from 4.02 to 5.02 mg/L, indicating a slight increase in the mean lethal concentrations as the exposure time increased. Results from this study indicate that interaction between these two parameters increases mortality and also suggest that dourado is susceptible to the combination of high ammonia with low dissolved oxygen concentrations. 相似文献
102.
Doron Schneider Martin Goldway Nitzan Rotman Itzhak Adato Raphael A. Stern 《Scientia Horticulturae》2009,122(3):380-384
‘Orri’, a selection of ‘Orha’ mandarin [Temple (Citrus temple hort. ex Y. Tanaka) × Dancy (Citrus tangerina hort. ex Tanaka)], is a new high-quality Israeli mandarin which, in the last decade, has become one of the leading varieties in Israel. ‘Orri’ has an excellent taste, the rind is deep orange in color and easily removed, and it contains few or no seeds. However, ‘Orri’ grown in Israel suffers from inadequate yield and no published studies have yet addressed this problem. In the present study we determined that ‘Orri’ productivity depended on conditions being favorable to cross-pollination. Under cross-pollination conditions a positive correlation (R2 = 0.97) was found between yield per tree and number of fruits per tree, and more than 90% of the fruits exceeded 60 mm: the most profitable size range. These data suggest that the number of fruits per tree, and not fruit size, is the limiting factor for yield improvement in ‘Orri’ orchards. Studying seed set showed that ‘Michal’ mandarin (Citrus reticulata Blanco) is a compatible pollenizer for ‘Orri’ flowers: the number of seeds per ‘Orri’ fruit increased as the distance from ‘Michal’ trees decreased. The present study demonstrated that cross-pollination of ‘Orri’ resulted in yield improvement, yet at the price of increased seed set. 相似文献
103.
Raphael A. Stern Amir Raz Steve Applebaum Ami Meiri Martin Goldway 《Scientia Horticulturae》2009,122(3):417-420
Small fruit size is one of the limiting factors in marketing cherries (Prunus avium L.). Several techniques have been used to improve fruit size; among them, blossom and fruit thinning in order to reduce crop load have proved effective. Unfortunately, hand thinning is very costly, and chemical thinning has proved ineffective. In the present study, carried out in two consecutive years (2006–2007), application of uniconazole (E-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl-1-penten-3-ol)) at 100–125 mg l−1, in the form of 0.2–0.25% Magic™, at 30% full bloom, reduced the fruit set of ‘Bing’ cherry fruit. As a result time spent in hand thinning was reduced by about 50% and the crop load by about 40%, and there was a considerable shift to larger fruit size (>26 mm), provided the crop load was not too low. No negative effects were observed on the return bloom and yield in the following year. 相似文献
104.
Yuanyuan YANG Yin ZHOU Zhou SHI Raphael A. VISCARRA ROSSEL Zongzheng LIANG Haizhen WANG Lianqing ZHOU Wu YU 《土壤圈》2020,30(6):817-831
The Tibetan Plateau of China is uniquely vulnerable to the global climate change and anthropogenic disturbances. As soil bacteria exert a considerable influence on the ecosystem function, understanding their response to different climates and land-use types is important. Here, we characterized the bacterial community composition and diversity across three major ecosystems (cropland, forest, and grassland) in the Sygera Mountains of Tibet, along a typical elevational gradient (3 300-4 600 m). The abundance of taxa that preferentially inhabit neutral or weak alkaline soil environments (such as Actinobacteria, Thermoleophilia, and some non-acidophilus Acidobacteria) was significantly greater in the cropland than in the forest and grassland. Furthermore, the diversity of soil bacterial communities was also significantly greater in the cropland than in the forest and grassland. We observed a unimodal distribution of bacterial species diversity along the elevation gradient. The dominant phyla Acidobacteria and Proteobacteria exhibited consistent elevational distribution patterns that mirrored the abundance of their most abundant classes, while different patterns were observed for Acidobacteria and Proteobacteria at the class level. Soil pH was the primary edaphic property that regulated bacterial community composition across the different land-use types. Additionally, soil pH was the main factor distinguishing bacterial communities in managed soils (i.e., cropland) from the communities in the natural environments (i.e., forest and grassland). In conclusion, land use (particularly anthropogenic disturbances such as cropping) largely controlled soil environment, played a major role in driving bacterial community composition and distribution, and also surpassed climate in affecting bacterial community distribution. 相似文献
105.
Raphael Oliveira de Melo Aymbiré Angeletti da Fonseca Nairam Félix de Barros Raphael Bragan?a Alves Fernandes Rafael da Silva Teixeira Iago Nery Melo Ricardo Previdente Martins 《林业研究》2022,(2):643-651
Eucalyptus harvesting,forwarding and soil tillage operations are among the main causes for compaction of forest soils,with potential impacts on productivity.This concern is especially important in areas with soils that are naturally compacted(fragipans and duripans).In these soils,tillage operations include the use of subsoilers that can reach depths of more than one meter and require heavy tractors that exert high pressure on the soil.One of the ways to try to minimize the effect of this compac... 相似文献
106.
107.
Robert M. Ewers Valerie Kapos David A. Coomes Raphael K. Didham 《Biological conservation》2009,142(12):2872-2880
Habitat loss is not randomly distributed across modified landscapes, yet spatial patterns of habitat cover are not routinely combined with biodiversity data when assessing or predicting the biodiversity impacts of land use change. Here, we convert point observations of more than 28,000 beetles from 851 species into a continuous biodiversity surface representing the similarity of ecological communities relative to that of pristine forest, effectively integrating on-the-ground biodiversity data with remotely sensed land cover data to predict the magnitude of community change in a modified landscape. We generated biodiversity surfaces for both present-day and pre-human landscapes to map spatial patterns of change in a diverse ecological community to calculate the combined biodiversity impacts of habitat loss and fragmentation that accounts for the exact spatial pattern of deforestation. Our spatially-explicit, landscape-scale index of community change shows how the fine-scale configuration of habitat loss sums across a landscape to determine changes in biodiversity at a larger spatial scale. After accounting for naturally occurring within-forest heterogeneity, we estimate that the conversion of 43% of forest to grassland in a 1300 km2 landscape in New Zealand resulted in a 47% change to the beetle community. 相似文献
108.
Gomes DI Véras RM Alves KS Detmann E Oliveira LR Mezzomo R Dos Santos RB de Sousa Barcelos S 《Tropical animal health and production》2012,44(7):1751-1757
This trial was conducted to assess the efficacy of a?ai seeds in the diet of sheep, specifically, to evaluate the intake, digestibility, and weight gain in sheep that are fed with diets containing four different mixtures of a?ai seeds and coastcross hay. Sixteen noncastrated male sheep with an average initial body weight of 22?kg were randomly assigned to one of four diet treatments using initial body weight as a covariate. The diets used coastcross hay as the basal roughage in a 60:40 roughage/concentrate ratio. The concentrate was the same in all the treatments. The a?ai seed was added to the diet as a partial substitute for the coastcross hay to make up four diet treatments: 0 (control), 5, 10, and 15?% a?aí added to the diet on a dry matter basis. The daily weight gain, final body weight, and feed intake were found to linearly increase with the increase in added dietary a?ai seed meal (P?0.05). Moreover, increasing the proportions of a?ai seed meal did not significantly alter the nutrient tract digestibility, except that the crude protein level declined in a linear manner. The inclusion of a?ai seed as a substitute for coastcross hay increases the intake and the daily weight gain in sheep that are fed with diets using coastcross hay as the basal roughage in a 60:40 roughage/concentrate ratio. 相似文献
109.
Elton Luís Ritir Oliveira Keylla H. N. Pacifico Pereira Daniel Angelo Felippi Paolla Nicole Franco Fabrício Singaretti de Oliveira Raphael A. Baldissera Gonçalves Luna Scarpari Rolim Bruno Cesar Schimming 《Anatomia, histologia, embryologia》2020,49(6):805-813
The aim of this study was to compare the arterial vascularization of the pelvic limb between southern caracara (Caracara plancus) and great egret (Ardea alba) by dissection and radiographic examinations. Five specimens of caracaras (three males and two females), and seven great egrets (five males and two females) were used. Barium sulphate and latex suspension were injected into the left ventricle of the birds. The radiographs were taken with the pelvic limbs in the ventrodorsal, dorsoplantar, mediolateral and lateromedial recumbency. Thereafter, the material was fixed in a 10% solution of formaldehyde and dissected. The pelvic limb received its arterial supply from two main vessels, the ischiatic and external iliac arteries. The ischiatic artery presented to be the principal artery of pelvic limb in the caracara and great egret. Several branches arised from the ischiatic and external iliac arteries were described. No gender differences were observed in both species. The caracara and great egret showed arteries similar to those reported for the ostrich and domestic fowl. According to the results of this study, it is suggested that the caracara has a pelvic limb with more arterial branches and larger arterial diameter than the great egret, which is probably related to the specific behaviour of these birds, since the caracara is a bird that exercise more their pelvic limbs to capture its prey when compared with the great egret. 相似文献
110.