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Effect of Temperature on Growth of Microhyla fissipes Tadpole
No full text为揭示温度对饰纹姬蛙(Microhyla fissipes)蝌蚪生长的影响,将同一家系发育至28期的45只蝌蚪随机均分为3组,每组15只,分别置于水温25、28、30 ℃条件下饲养,测定其全长、体宽、眼距、吻长及头体长5项形态指标,分析不同温度下各项形态指标的变化。结果显示,5项形态特征有基本一致的变化趋势,其中全长最易表征蝌蚪的生长状况。从全长看,25 ℃组蝌蚪生长发育缓慢,但在12 d后有加快的趋势;30℃组在饲养第3~12d,生长最迅速(增长率beta = 50.05%),但在12 d后生长明显变缓(beta = 9.42%),而到28 d时,已有较多蝌蚪死亡(5/15); 28 ℃组的蝌蚪生长发育态势最好,且在饲养第28 d均超过30 ℃组,其在3d后加快的生长趋势也强于25 ℃组。其他4项指标与全长有类似的结果。综合结果分析表明,30 ℃下蝌蚪在后期(21d后)的成活率明显降低,而25 ℃下其生长缓慢,提示28 ℃是饰纹姬蛙蝌蚪比较适合的饲养温度
Males increase call frequency, not intensity, in response to noise, revealing no Lombard effect in the little torrent frog
No full textNoise is one of the main factors that can influence the processes of sound communication across a wide range of animal groups. Although the effects of ambient noise on animal communication, including anthropogenic noise, have received increasing attention, few studies have examined changes in the fine structure of acoustic signals produced by vocalizing species in constantly noisy environments. Here, we used natural recordings to determine the associations between stream noise and call parameters in the little torrent frog (Amolops torrentis). We also used playbacks of stream noise recorded in natural habitats and playbacks of white noise to examine how male vocal signals change with increasing noise levels. The results show that noise intensity has a significant effect on male call frequency, but not on call amplitude or other call characteristics. Based on this evidence, we suggest that in streamside species stream noise drives males to alter call frequency and call as loudly as possible in order to improve discriminability. These findings provide insights into the role played by ecological selection in the evolution of noise-dependent anuran vocal plasticity
Distinct effects of N and P addition on soil enzyme activities and C distribution in aggregates in a subalpine spruce plantation
No full textNitrogen (N) and phosphorus (P) have a critical role in soil carbon (C) cycling, but the mechanisms underlying the responses of soil C dynamics to N and P availability remain unclear because both N and P addition have divergent effects on different soil C pools. Here, we studied enzyme activities and C dynamics in bulk soil and three aggregate fractions, i.e. macroaggregates (5000-250m; MaA), microaggregates (250-53m; MiA) and silt and clay (<53m; S&C), following two growing seasons of N addition (0, 5 and 20gNm(-2)y(-1)) fully crossed with P addition (15gPm(-2)y(-1)) in a subalpine spruce plantation. We found increased activities of two oxidases (catalase and polyphenol oxidase) in bulk soil following N and P addition. -glucosidase activity was suppressed by N in MiA (-34%) and S&C (-23%) but increased by P in MaA (+35%). P addition increased catalase activity of S&C (+20%). Bulk soil C content showed no significant response to N or P addition, whereas C distribution in soil aggregates was affected, with increased relative C content of S&C in N-only addition plots (+53%) and increased relative C content of MaA after P addition (+11%). Our results demonstrated divergent sensitivities of both C pools and enzyme activities in different soil aggregates to fertilization, which can enhance our understanding of the responses of bulk soil C pool and enzyme activities to fertilization
Description and initial characterization of metatranscriptomic nidovirus-like genomes from the proposed new family Abyssoviridae, and from a sister group to the Coronavirinae, the proposed genus Alphaletovirus
No full textTranscriptomics has the potential to discover new RNA virus genomes by sequencing total intracellular RNA pools. In this study, we have searched publicly available transcriptomes for sequences similar to viruses of the Nidovirales order. We report two potential nidovirus genomes, a highly divergent 35.9 kb likely complete genome from the California sea hare Aplysia californica, which we assign to a nidovirus named Aplysia abyssovirus 1 (AAbV), and a coronavirus-like 22.3 kb partial genome from the ornamented pygmy frog Microhyla fissipes, which we assign to a nidovirus named Microhyla alphaletovirus 1 (MLeV). AAbV was shown to encode a functional main proteinase, and a translational readthrough signal. Phylogenetic analysis suggested that AAbV represents a new family, proposed here as Abyssoviridae. MLeV represents a sister group to the other known coronaviruses. The importance of MLeV and AAbV for understanding nidovirus evolution, and the origin of terrestrial nidoviruses are discussed
Auditory sensitivity exhibits sexual dimorphism and seasonal plasticity in music frogs
No full textSeasonal changes in the structure and function of the vertebrate brain have been described in many species, particularly in seasonal breeders. However, it remains unclear whether sexual dimorphism varies between breeding seasons for specific brain regions. Auditory event-related potential (ERP) changes were evaluated in the Emei music frog (Babina daunchina) to assess sexual dimorphism and seasonal variations in auditory sensitivity. An acoustic playback experiment using an oddball paradigm design was conducted, in which two conspecific call types were used as deviant stimuli with synthesized white noise as standard stimulus. ERP components were analyzed for the telencephalon and mesencephalon of both sexes in the non-reproductive and reproductive states. Results show that auditory sensitivity is modulated by reproductive status, implying that seasonal plasticity is involved in auditory perception. Moreover, the amplitude of the N1 ERP component (mean amplitudes during the interval occurring 30-130ms after stimulus onset) is higher in females for the telencephalon and higher in males for the mesencephalon, regardless of reproductive status and acoustic stimulus type. These results show that auditory ERP responses for specific brain regions exhibit sexual dimorphism in the absence of exogenous sexual stimulation during both the two reproductive states in the music frog
Genome-wide researches and applications on Dendrobium
No full textMain conclusion This review summarizes current knowledge of chromosome characterization, genetic mapping, genomic sequencing, quality formation, floral transition, propagation, and identification in Dendrobium. The widely distributed Dendrobium has been studied for a long history, due to its important economic values in both medicine and ornamental. In recent years, some species of Dendrobium and other orchids had been reported on genomic sequences, using the next-generation sequencing technology. And the chloroplast genomes of many Dendrobium species were also revealed. The chromosomes of most Dendrobium species belong to mini-chromosomes, and showed 2n = 38. Only a few of genetic studies were reported in Dendrobium. After revealing of genomic sequences, the techniques of transcriptomics, proteomics and metabolomics could be employed on Dendrobium easily. Some other molecular biological techniques, such as gene cloning, gene editing, genetic transformation and molecular marker developing, had also been applied on the basic research of Dendrobium, successively. As medicinal plants, insights into the biosynthesis of some medicinal components were the most important. As ornamental plants, regulation of flower related characteristics was the most important. More, knowledge of growth and development, environmental interaction, evolutionary analysis, breeding of new cultivars, propagation, and identification of species and herbs were also required for commercial usage. All of these studies were improved using genomic sequences and related technologies. To answer some key scientific issues in Dendrobium, quality formation, flowering, self-incompatibility and seed germination would be the focus of future research. And genome related technologies and studies would be helpful
Shrub encroachment alters topsoil C:N:P stoichiometric ratios in a high-altitude forest cutover
No full textThe effect of shrub encroachment on soil carbon (C): nitrogen (N): phosphorus (P) stoichiometric ratios are largely still unknown. We investigated this effect and the effect of shrub size in a high altitude forest cutover among four common shrub species: Cerasus trichostoma, Ribes glaciate, Rosa omeiensis and Salix sphaeronymphe. The difference in topsoil C:N ratio between meadows and shrub islands was greatly influenced by shrub species and plant sizes. Topsoil N:P and C:P ratios were always higher in shrub islands than in meadows, irrespective of shrub species and plant size. The expansion of shrubs merely increased the topsoil C:N ratio beneath Cerasus and Rosa, and increased the topsoil N:P and C:P ratios beneath the four shrub species. The increase in stoichiometric ratio followed an identical pattern among the four shrub species as shrub size increased. There were always higher topsoil C:P and N:P ratios beneath Ribes than under the other shrub species with the same plant size. This study clearly suggests that the effect of shrub islands on soil C:N:P stoichiometric ratios was dependent on shrub species and size. Our results are conducive to clarifying the currently confusion in secondary successional trends of soil C:N:P stoichiometry
Balancing straw returning and chemical fertilizers in China: Role of straw nutrient resources
No full textCurrently, large-scale farmland degradation resulted from the overuse of chemical fertilizers has become a major issue in China. Meanwhile, a large sum of straw nutrient resources have been lost from the farmland due to the straw removal from fields, which in return aggravated the degradation in farmland quality and long-term productive capacity of soil resources. Whether current straw management practices represent rational utilization and how straw can be used more efficiently have become the most important but least studied problems for China's green agricultural development. Based on the China's Official Statistics, we first collected a large number of data on the annual crop yields, crop sown areas and chemical fertilizer consumption of different crop types in 31 China's mainland provinces from 1998 to 2014. Straw yields and straw nutrient resources were calculated to assess the potential contribution of straw resources to chemical fertilizers. Our estimation demonstrates that straw returning to farmlands could counterbalance all of the K2O, the majority of the P2O5, and a portion of the N in chemical fertilizers. Promoting the return of straw to field has a great potential to reduce the use of chemical fertilizer, air pollutant emission and environmental burden. Thus, we propose that the Chinese government should adjust the policies to take promoting straws returned to field as priority, instead of greatly encouraging straw removal from field. Innovative straw decomposing technologies and returning practices are also needed to assure China's green agricultural development and reduce environmental pollution in the future
四川省国家Ⅱ级保护植物新记录——半枫荷
No full text报道了四川省金缕梅科植物新纪录种半枫荷,该植物为国家Ⅱ级重点保护野生植物,同时半枫荷属也是四川省新纪录属。这一新发现,进一步丰富了四川省的生物多样性资料,也为华西雨屏带与云贵高原的植物区系联系提供了新资料
Pedobacter chitinilyticus sp. nov., a chitin-degrading bacterium isolated from wheat leaf tissue
No full textA bacterium, designated strain CM134L-2(T), was isolated from a chitin-enriched wheat leaf microbiome in Chengdu, Sichuan province, China. It was Gram-stain-negative, strictly aerobic, non-spore-forming, motile, rod-shaped, and bright yellow in colour. Strain CM134L-2(T) grew at 4-35 degrees C, at pH 6.0-9.0 and could use chitin as the only carbon resource. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain CM134L-2(T) was most closely related to Pedobacter nanyangensis Q-4(T) (97.7 %) and Pedobacter zeaxanthinifaciens TDMA-5(T) (97.4 %). Digital DNA-DNA hybridization (dDDH) values between strain CM134L-2(T) with these two type strains were 26.8 and 20.8 %, respectively, and average nucleotide identity (ANI) values were 83.2 and 76.2 %; these values are lower than the proposed and generally accepted species boundaries of 70 % for dDDH and 95-96 % for ANI, which suggests strain CM134L-2(T) represents a novel species. The genomic DNA G+C content of strain CM134L-2(T) was 39.3 mol%, menaquinone-7 was the major respiratory quinone, phosphatidylethanolamine was the major polar lipid and the major components of the cellular fatty acids were iso-C-15:0, and C-16 :1 omega 7c/C-16:1 omega 6C (summed feature 3); these features supported the affiliation of strain CM134L-2(T) to the genus Pedobacter. Overall, strain CM134L-2(T) belongs to the genus Pedobacter, but can be classified as a novel species, for which the name Pedobacter chitinilyticus sp. nov. is proposed. The type strain is CM134L-2(T) (=CGMCC 1.16520(T)=KCTC 62643(T))