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101.
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Low salinity increases survival,body weight and development in tadpoles of the Chinese edible frog Hoplobatrachus rugulosus 下载免费PDF全文
La‐iad Nakkrasae Sukpaporn Phummisutthigoon Narattaphol Charoenphandhu 《Aquaculture Research》2016,47(10):3109-3118
Water salinity affects survival, growth and metamorphosis of anuran tadpoles. Hoplobatrachus rugulosus is considered not only as a freshwater amphibian but is also found in brackish wetlands. However, whether salinity change interferes with hatching, survival, body mass and development of H. rugulosus tadpoles is unknown. We found that salinity levels of <4‰ did not affect of survival or hatching of H. rugulosus eggs. At an early larval stage, tadpoles could tolerate up to 9‰ salinity for 96 h; however, body water content decreased when salinity was >5‰. After a 3‐week experiment, body weights of tadpoles exposed to 2‰ and 4‰ salinities were higher but that of the 6‰ group was lower compared with the 0‰ group. More than 90% of tadpoles exposed to 2‰ and 4‰ salinity showed complete metamorphosis. Salinity levels <4‰ promoted survival of tadpoles better than 0‰, whereas none of tadpoles in the 6‰ group became juvenile frogs in 50 days. Time taken to reach metamorphosis was shorter for 2‰ and 4‰ (47.22 ± 0.28 and 47.26 ± 0.33 days, respectively) than for 0‰ (49.31 ± 0.35 days). Juvenile frogs in the 2‰ group had greater body weight than the control. It could be concluded that salinity of <4‰ increased survival and body weight of H. rugulosus tadpoles, and shortened the time taken to reach metamorphosis. 相似文献
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杂交相思组织培养研究初报 总被引:1,自引:0,他引:1
【目的】筛选杂交相思组织培养不同培养阶段的培养基配方,为实现杂交相思工厂化育苗提供技术参考。【方法】用杂交相思嫩茎为外植体,探究生长调节剂6-BA、NAA、IBA对其诱导出芽、继代增殖和诱导生根的效果。【结果】在不添加6-BA的情况下,添加0.2mg/LNAA时芽诱导率为60.0%,当添加0.2mg/L的6-BA后,诱导率为42.0%。当NAA为0~0.5mg/L时,随着6-BA的增加,增殖系数随之增加,6-BA为0.8mg/L时,增殖系数为4.2;当6-BA为1.0mg/L以上时,继代苗的增殖系数为1.0。以改良MS为基本培养基,在NAA1.0mg/L的条件下添加0.5、1.0mg/L的IBA生根诱导率分别为17.5%、24.0%;以改良1/2MS为基本培养基,在NAA1.0mg/L的条件下,添加0.5mg/L的IBA生根率为91.7%,当添加IBA为1.0mg/L时,生根率降到50.0%;生根苗移栽基质以黄心土与河沙或蛭石混合较好,移栽成活率在85.0%以上。【结论】改良MS+NAA0.2mg/L培养基是较适宜芽诱导的培养基;改良MS+6-BA0.8mg/L+NAA0.5mg/L培养基较利于继代苗的生长;改良1/2MS+NAA1.0mg/L+IBA0.5mg/L培养基较改良MS培养基有利于诱导生根。 相似文献
105.
N. La Porta M. Zacchini S. Bartolini R. Viti G. Roselli 《The Journal of Horticultural Science and Biotechnology》2013,88(3):433-435
SummaryFrost hardiness of four olive clones (Olea europaea L.) belonging to cv. Leccino was studied and compared with that of a susceptible clone of cv. Moraiolo by ionic leakage. Variability of the trait was found within the clones of ‘Leccino’, some of which were statistically different from a the ‘Moraiolo’ clone at one or both temperatures tested. Only one clone showed a significant difference between ?15° and ?20°C. The ionic leakage technique is appropriate for studying changes in physical properties of membranes and its use in the screening of frost tolerant olive clones is discussed. 相似文献
106.
This work investigated the effects of land cover and land-use change (LUC) on the ability of a soil to store carbon (C) and reduce carbon dioxide (CO2) emissions, in a Mediterranean area. Using a paired-site approach, we estimated the effect of land-cover change on the C stock from 1972 to 2008 in a natural reserve (Grotta di Santa Ninfa) in western Sicily. We selected 15 paired sites representative of five LUCs. We studied the effect of land use on soil organic C (SOC) content in bulk soil and in different particle-size fractions (2000-1000 μm, 1000-500 μm, 500-250 μm, 250-63 μm, 63-25 μm, and < 25 μm). Laboratory incubation of the soil samples was conducted to measure CO2 evolution in bulk soil collected at two different depths from each paired site. We found that the conversion of natural vegetation to orchards (vineyards and olive groves) resulted in SOC decreases ranging from 27% to 50%. The conversion from vineyards to arable land led to a 9% decrease in SOC, whereas the opposite caused a 105% gain. When arable land was replaced by Eucalyptus afforestation, a 40% increase in SOC was observed. SOC decline occurred mainly in coarser soil fractions, whereas the finest fractions were not influenced by land use. We calculated an overall SOC reduction of 63% in the study area, corresponding to a 58 Mg ha− 1 SOC loss in less than 30 years. Our results indicate that land-use conversion, vegetation type, and management practices that control the biogeochemical and physical properties of soil could help reduce CO2 emissions and sequester SOC. 相似文献
107.
F. Scarciglia V. Zumpano R. Sulpizio F. Terribile I. Pulice M. F. La Russa 《European Journal of Soil Science》2014,65(4):406-419
In this paper the role of time and late Pleistocene to middle Holocene climate changes in the Somma‐Vesuvius volcano foothill (southern Italy) is investigated with a multidisciplinary approach. Four volcanic soils inter‐layered between five well‐known and well‐dated primary tephra layers were characterized. Chronological constraints were provided by the pyroclastic layers identified in the field (Pomici di Base, Pomici Verdoline, Agnano Pomici Principali, Mercato and Avellino), ranging between 22 and 3.8 thousand years (ka) before present (BP). These represent products of explosive eruptions of Somma‐Vesuvius and the Phlegrean Fields. Another pyroclastic layer (Agnano Monte Spina) from the Phlegrean Fields was also identified, and other ash layers previously unknown in the Somma‐Vesuvius stratigraphy. These were characterized with SEM‐EDS analyses, and correlated with other eruptions from the Phlegrean Fields (Soccavo 4‐5 and Tufi Biancastri) around 12 and 21 ka BP, respectively, thus resulting in further time constraints for phases of soil development. A detailed characterization of the four pedons integrated morphological, physical, chemical, mineralogical and micromorphological analyses. Soil features were interpreted in terms of dominant genetic processes and environmental conditions. The extent of soil development, assessed with pedogenetic indices and the degree of weathering of primary pumices, was only in part consistent with time‐spans of soil formation, suggesting a more important role of climate than soil age. The different extents of expression of andic properties, pumice weathering and varying clay mineralogy allowed us to relate changes to the main climatic phases that occurred during the late Pleistocene to the mid Holocene. 相似文献
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La T Phillips ND Wanchanthuek P Bellgard MI O'Hara AJ Hampson DJ 《Veterinary microbiology》2011,153(1-2):150-155
Swine dysentery (SD) results from infection of the porcine large intestine with the anaerobic intestinal spirochaete Brachyspira hyodysenteriae. Recently the genome of virulent Australian B. hyodysenteriae strain WA1 was sequenced, and a 36 kilobase (kb) circular plasmid was identified. The plasmid contained 31 genes including six rfb genes that were predicted to be involved with rhamnose biosynthesis, and others associated with glycosylation. In the current study a set of PCRs was developed to amplify portions of nine of the plasmid genes. When used with DNA extracted from virulent strain B204, PCR products were generated, but no products were generated with DNA from avirulent strain A1. Analysis of the DNA using pulsed field gel electrophoresis (PFGE) identified a plasmid band in strains WA1 and B204, but not in strain A1. These results demonstrate that strain A1 does not contain the plasmid, and suggests that lack of the plasmid may explain why this strain is avirulent. To determine how commonly strains lacking plasmids occur, DNA was extracted from 264 Australian field isolates of B. hyodysenteriae and subjected to PCRs for three of the plasmid genes. Only one isolate (WA400) that lacked the plasmid was identified, and this absence was confirmed by PFGE analysis of DNA from the isolate and further PCR testing. To assess its virulence, 24 pigs were experimentally challenged with cultures of WA400, and 12 control pigs were challenged with virulent strain WA1 under the same conditions. Significantly fewer (P=0.03) of the pigs challenged with WA400 became colonised and developed SD (13/24; 54%) compared to the pigs infected with WA1 (11/12; 92%). Gross lesions in the pigs colonised with WA400 tended to be less extensive than those in pigs colonised with WA1, although there were no obvious differences at the microscopic level. The results support the likelihood that plasmid-encoded genes of B. hyodysenteriae are involved in colonisation and/or disease expression. 相似文献
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