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161.
马尾松受害诱导的化学物质滞后变化 总被引:14,自引:3,他引:11
通过接种马尾松毛虫Dendrolimus punctatus和人工剪叶,分析比较了不同受害方式对马尾松针叶内化学物质的影响。结果表明,害虫取食松针诱导的次生代谢物质(单宁、酚类物质)比人工剪叶处理略有增加,而营养物质-可溶性糖变化不大。对马尾松进行害虫取食为害、人工剪叶受害、未受害三种处理后,连续3年跟踪测定了松针叶内化学物质含量的变化。结果发现,无论是害虫取食为害,还是人工剪叶受害,针叶内次生代谢物质含量都减少,可溶性糖含量降低,直至一年后才恢复到原有的水平;蛋白质变化的趋势则始终是受害处理的含量比未受害处理的含量高,表明马尾松受害后诱导的化学物质变化具有滞后特性。 相似文献
162.
163.
Artificial selection of individuals has been determinant in the elaboration of the Darwinian theory of natural selection. Nowadays, artificial selection of ecosystems has proven its efficiency and could contribute to a theory of natural selection at several organisation levels. Here, we were not interested in identifying mechanisms of adaptation to selection, but in establishing the proof of principle that a specific structure of interaction network emerges under ecosystem artificial selection. We also investigated the limits in ecosystem artificial selection to evaluate its potential in terms of managing ecosystem function. By artificially selecting microbial communities for low CO2 emissions over 21 generations (n = 7560), we found a very high heritability of community phenotype (52%). Artificial selection was responsible for simpler interaction networks with lower interaction richness. Phenotype variance and heritability both decreased across generations, suggesting that selection was more likely limited by sampling effects than by stochastic ecosystem dynamics. 相似文献
164.
165.
目的: 观察研究年轻健康正常人的静息桡动脉脉搏波特征及单次个体化运动后脉搏波的变化情况。方法: 选取阜外医院年轻健康、无任何疾病诊断的正常人16例,首先完成症状限制性极限心肺运动试验(CPET),根据CPET计算Δ50%功率为个体化精准运动强度,完成持续30 min的单次运动。于运动前和运动后10 min、20 min、30 min分别测量50 s桡动脉脉搏波,先用软件自动定点再人工复检得到每个脉搏波特征点:起始点(B)、主波波峰点(P1)、重搏波波谷点(PL)、重搏波波峰点(P2)、结束点(E),从仪器中导出各点对应的横坐标(时间T)和纵坐标(幅值Y)的原始数据,将上一个脉搏波的结束点E视为下一个波的起始点B,TB归零,得到主要观察指标:YB、YP1、YPL、YP2及TP1、TPL、TP2、TE,并计算出ΔYP1(YP1-YB)、ΔYPL(YPL-YB)、ΔYP2(YP2-YB),TE-TPL、(TE-TPL)/TPL、脉率,S1(主波升支斜率)、S2(重搏波升支斜率),ΔYP2-ΔYPL、TP2-TPL作为次要观察指标;定义波峰明显的重搏波为YP2>YPL,计算波峰明显的重搏波出现率(50 s内YP2>YPL的波形个数/波形总个数×100%);对每位患者运动前后的50 s脉搏波数据个体化分析,再将所有数据求均值进行整体分析。结果: ①16例年轻健康受试者(男10女6),年龄(30.6±6.4,24~48)岁;身高(170.4±8.2, 160~188)cm;体质量(63.9±12.8, 43~87)kg。②静息时YB(87.2±5.8,78.1~95.9)、YP1(223.5±15.8,192.7~242.3)、YPL(122.8±7.8,110.0~133.8)、YP2(131.4±4.9,116.7~137.5)、TP1(126.2±42.2,94.2~280.0)、TPL(360.2±44.8,311.5~507.3)、TP2(432.4±50.8,376.2~589.0)、TE(899.7±86.9,728.3~1042.0);ΔYP1(136.3±19.9,96.8~158.6)、ΔYPL(35.7±10.7,16.0~55.7)、ΔYP2(44.3±8.1,22.5~56.5)、TE-TPL(539.5±79.3,405.9~691.3)、(TE-TPL)/TPL(1.5±0.3,0.8~2.0)、脉率(67.3±6.6,57.6~82.4)、S1(1.1±0.2,0.6~1.4)、S2(0.1±0.1,0.0~0.2)、ΔYP2-ΔYPL(8.6±6.1,0.9 ~19.8)、TP2-TPL(72.3±19.9,38.3~108.4)。③运动后10 min, YPL(97.0±13.2比122.8±7.8)、YP2(109.6±12.8比131.4±4.9)、ΔYPL(6.6±9.8比35.7±10.7)、ΔYP2(19.3±11.2比44.3±8.1)显著减小,TE(667.8±123.1比899.7±86.9)、TE-TPL(330.2±128.4比539.5±79.3)、(TE-TPL)/TPL(1.0±0.4比1.5±0.3)显著减小,而脉率(92.2±14.0比67.3±6.6)、ΔYP2-ΔYPL(12.7±9.7比8.6±6.1)、 TP2-TPL(98.0±38.1比72.3±19.9)显著增大(P均<0.05)。运动后20 min和30 min的脉搏波变化趋势与运动后10 min保持一致,但从20 min开始大部分指标逐渐向运动前静息水平恢复。④静息时16例正常人波峰明显的重搏波出现率为94.5%,运动后10 min(96.3%)、20 min(98.5%)、30 min(99.8%)的出现率升高(P均<0.01)。其中10例运动前后波峰明显的重搏波出现率均维持在100%左右;2例运动前出现率已达100%,但运动后10 min有所降低,后又继续升高,30 min时恢复到100%;3例静息出现率偏低,运动后升高近100%;还有1例仅运动后20 min出现率偏低,考虑人为因素影响。结论: 运动对正常人脉搏波的影响主要体现在重搏波上;整体上看,单次精准功率运动后,重搏波位置降低、幅度加深,波峰明显的重搏波出现率普遍提高,且这种改变至少能维持30 min;从个体上看,每位受试者的反应又有所不同。 相似文献
166.
Fabiola NietoRabiela Oscar RicoChvez Gerardo Suzn Christopher R. Stephens 《Ecology and evolution》2021,11(11):6305
Understanding the assembly processes of symbiont communities, including viromes and microbiomes, is important for improving predictions on symbionts’ biogeography and disease ecology. Here, we use phylogenetic, functional, and geographic filters to predict the similarity between symbiont communities, using as a test case the assembly process in viral communities of Mexican bats. We construct generalized linear models to predict viral community similarity, as measured by the Jaccard index, as a function of differences in host phylogeny, host functionality, and spatial co‐occurrence, evaluating the models using the Akaike information criterion. Two model classes are constructed: a “known” model, where virus–host relationships are based only on data reported in Mexico, and a “potential” model, where viral reports of all the Americas are used, but then applied only to bat species that are distributed in Mexico. Although the “known” model shows only weak dependence on any of the filters, the “potential” model highlights the importance of all three filter types—phylogeny, functional traits, and co‐occurrence—in the assemblage of viral communities. The differences between the “known” and “potential” models highlight the utility of modeling at different “scales” so as to compare and contrast known information at one scale to another one, where, for example, virus information associated with bats is much scarcer. 相似文献
167.
168.
Andrey Pshenichnov Oleg Balanovsky Olga Utevska Ene Metspalu Valery Zaporozhchenko Anastasia Agdzhoyan Mikhail Churnosov Lyubov Atramentova Elena Balanovska 《American journal of physical anthropology》2013,152(4):543-550
The area of what is now the Ukraine has been the arena of large‐scale demographic processes that may have left their traces in the contemporary gene pool of Ukrainians. In this study, we present new mitochondrial DNA data for 607 Ukrainians (hypervariable segment I sequences and coding region polymorphisms). To study the maternal affinities of Ukrainians at the level of separate mitochondrial haplotypes, we apply an original technique, the haplotype co‐occurrence analysis. About 20% of the Ukrainian maternal gene pool is represented by lineages highly specific to Ukrainians, but is scarcely found in other populations. About 9% of Ukrainian mtDNA lineages are typical for peoples of the Volga region. We also identified minor gene pool strata (1.6–3.3%), each of which is common in Lithuanians, Estonians, Saami, Nenets, Cornish, and the populations of the North Caucasus. Am J Phys Anthropol 152:543–550, 2013. © 2013 Wiley Periodicals, Inc. 相似文献
169.
Ibtissem Ben Fekih Sonia Boukhris-Bouhachem Mohamed Bechir Allagui Annette Bruun Jensen Jørgen Eilenberg 《法国昆虫学会纪事》2013,49(2):140-144
Summary. The natural occurrence of fungal pathogens of aphids and their ecological host range was investigated in Tunisia from 2009 to 2012. The survey focused on aphid infesting different crops and weeds and included 10 different aphid species. Samples were collected from eight agricultural crops sites belonging to three different bioclimatic zones. Four pathogens from the phylum Entomophthoromycota were found to occur naturally in Tunisian ecosystems: Pandora neoaphidis (Entomophthorales: Entomophthoraceae), Entomophthora planchoniana (Entomophthorales: Entomophthoraceae), Conidiobolus obscurus (Entomophthorales: Ancylistaceae) and Neozygites fresenii (Neozygitales: Neozygitaceae). The occurrence of entomophthoralean fungi depended on the sampling area, the bioclimatic zone, and aphid species. P. neoaphidis and E. planchoniana were the predominant pathogens infecting a wide range of aphid species whereas C. obscurus and N. fresenii were sporadically present on a limited number of aphid species. This study is the first survey on ecological host range of entomophthoralean fungi in Tunisia, and the first documentation of C. obscurus and N. fresenii to occur in Tunisia and Maghreb Region. 相似文献
170.
Milad Aeini Hossein Mirzaee Seyed Mohsen Taghavi Gholam Reza Khodakaramian Mehdi Amiri Mazhar 《Archives Of Phytopathology And Plant Protection》2013,46(18):2257-2262
Ficus benjamina, commonly known as weeping fig, Benjamin’s fig or Ficus tree is a species of flowering plant in the family of Moraceae. It is native to south and south-east Asia and Australia. Crown gall tumours were collected from branches of one-year-old weeping fig (F. benjamina L.) trees. A total of 50 strains of Agrobacterium tumefaciens were isolated from diseased Ficus plants and their morphological, molecular and biochemical characteristics were studied; pathogenicity tests on tomato, F. benjamina and Bryophyllum daigremontianum were also conducted. Based on the biochemical characteristics, pathogenicity test and PCR amplification of 730?bp fragment using VCR\VCF primers, the tested bacterial strains were identified as A. tumefaciens. This is the first report of crown gall on F. benjamina in Isfahan and Fars provinces of Iran. 相似文献