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21.
Reconstructing the phylogeny of the sexually deceptive orchid genus Ophrys is crucial to our understanding of the evolution of its complex floral morphology. Molecular phylogenetic analyses showed that section Pseudophrys forms a well supported clade with Ophrys bombyliflora, O. tenthredinifera and O. speculum, but were unable to elucidate the relationships between these four groups of taxa. Here we conduct a morphological phylogenetic analysis of this unresolved clade of Ophrys based on a data matrix of 45 macro‐ and micromorphological and anatomical floral characters, using maximum parsimony and Bayesian inference. Our cladistic analysis yielded a single most parsimonious tree and a Bayesian 50% majority‐rule consensus tree which differed in their overall topology but agreed that O. tenthredinifera and O. bombyliflora are not sister groups. The phylogenetic placement of O. tenthredinifera was ambiguous since it shares six valid synapomorphies each with the cluster of O. speculumO. bombyliflora and with section Pseudophrys. In contrast, O. bombyliflora is most likely the sister group to O. speculum, a finding that rejects an earlier morphological phylogenetic hypothesis and favours the existing molecular trees based on nuclear ITS rather than plastid data. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 179 , 454–476.  相似文献   
22.
【目的】测定黄粉虫Tenebrio molitor Linnaeus幼虫抗菌肽提取液的浓度、抑菌活性及其部分生化特性和凝血效应。【方法】本实验用浓度为1×108 CFU/m L大肠杆菌Escherichia coli诱导5龄黄粉虫幼虫,分别在诱导12、24、36、48、60和72 h后提取其中的抗菌肽,并用考马斯亮兰法测定抗菌肽粗提液蛋白的浓度,并用滤纸片法测定其抑菌活性,同时对其热稳定性、反复冻融稳定性、蛋白酶稳定性及不同p H对其活性的影响等生化特性及凝血效应进行了探究。【结果】经大肠杆菌诱导的黄粉虫抗菌肽粗提液的蛋白浓度均显著高于未诱导的黄粉虫组(P<0.01),且在诱导48 h时产生的抗菌肽提取液蛋白的浓度最高,产生的抑菌圈直径也显著高于未诱导的黄粉虫组(P<0.05),生化特性的测定结果显示,黄粉虫抗菌肽有较好的热稳定性、酶稳定性及酸碱稳定性,反复冻溶后对其抑菌活性影响不大,并且无凝血效应。【结论】大肠杆菌可以刺激黄粉虫的免疫系统,增加抗菌肽的表达量,使其产生浓度高、活性强的抗菌肽,且生化特性较稳定。本研究对黄粉虫抗菌肽作为绿色抗生素用于畜牧养殖业的进一步开发与利用提供了科学的理论依据。  相似文献   
23.
Population response to selection depends on the presence of additive genetic variance for traits under selection. When a population enters an alien environment, environment-induced changes in the expression of genetic variance may occur. These could have large effects on the response to selection. To investigate the environment-dependence of genetic variance, we conducted a reciprocal transplant experiment between two ecotypically differentiated populations of Impatiens pallida using the progeny of a standard mating design. The floodplain site was characterized by high water availability, moderate temperatures, and continuous dense stands of Impatiens. The hillside site was drier, with larger temperature extremes and supported only scattered patches of Impatiens with significantly lower seed production and earlier mortality. Estimates of heritability were low for each of the 13 traits measured in each population and site (range from 0–28%). Additive genetic variance for life-history traits tended to be larger than for morphological traits, but genetic variance in fitness was estimated to be not significantly different from zero in all cases. Significant heritability was detected in both populations for one trait (date of first cleistogamous flower) known to be closely related to fitness on the hillside. In general, heritability was reduced for populations when grown in the hillside site relative to the floodplain site, suggesting that stress acts to reduce the expression of genetic variance and the potential to respond to selection there. Consistent reductions in heritability associated with more stressful environments suggest that populations invading such sites may undergo little adaptive differentiation and be more prone to local extinction.  相似文献   
24.
Ophiocordyceps pulvinata, a pathogen of ants, is formally described as a new species. Genus level designation of this species is difficult due to several apparently conflicting morphological and ecological characters. Affinity with Ophiocordyceps is suggested by the dark color stroma and ascospore morphology. However, the species was included in a book of entomopathogenic fungi of Japan as Torrubiella sp. due to the production of perithecia on an astipitate stroma. Phylogenetic analyses of molecular data support a close relationship with O. unilateralis, a finding consistent with morphological characteristics of the color, asci and ascospores and ecological traits of host affiliation. Thus, O. pulvinata represents another example of the loss of stipe for the hypocrealean arthropod pathogenic fungi and highlights the utility of asci and ascospore morphology as taxonomically informative characters of closely related taxa.  相似文献   
25.
为将20份新收集(引进)、选育的烤烟种质资源入国家种质库进行编目和保存,对各种质进行田间鉴定评价,结果表明,云烟317、云烟201、云烟202、云烟203、PVH09和RGH51等品种抗或中抗黑胫病、根结线虫病、青枯病、TMV等主要病害中的2种以上,产量适中、品质较好,已经全国烟草品种审定委员会审(认)定,其余种质资源在田间生长正常,白花大金元、江川地方种、大有种和人民六队-15黑胫病较重。田间试验获得了各种质的生育期、形态特征、主要农艺性状、经济性状、原烟外观质量、化学成分和主要病害等数据资料,拍摄了各种质的植株、叶片、花序、花冠和蒴果的照片,按规定上交合格种子并入库保存,获得的资料全部上交给中国农业科学院烟草研究所,用于中国烟草种质资源信息系统和共享平台建设,为丰富国家种质库以及今后持续利用种质资源奠定良好基础。  相似文献   
26.
The effects of different coding practices in morphological phylogenetic analysis are well documented. In many cases, we can determine that certain practices can be regarded as undesirable and should be avoided. Certain coding practices do not correctly translate the expected information to the cladistic algorithm. It may go unnoticed that expressions of character information in character lists, which may be entirely logical to any reader, do not necessarily reflect the mathematics employed by a phylogenetic algorithm. Despite a wealth of literature on coding procedures and documentation of these issues, problematic character coding practices are still common. A review is provided of different coding and character formulation practices, particularly relating to multistate character information that may either: (1) lead to a failure to capture grouping information implied in the character list; (2) cause problematic weighting or spuriously high certainty in particular optimizations; and (3) impose congruence artificially, by linking more than one variable character to a particular state. Each of these is reviewed and presented with a hypothetical example. Recommendations for avoiding these pitfalls are described in light of how parsimony algorithms work with character data. Character lists must be drawn up not only to present character variation logically, but also with consideration for how computer algorithms implement cladistic logic. The widespread use of problematic character coding procedures may account for some of the perceived problems with morphological data. Therefore, an exploration of the effects of these methods and standardization of methods should be a goal for the very near future. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 104 , 489–498.  相似文献   
27.
阮祥锋  溪波 《动物学杂志》2011,46(5):146-150
摘要:发冠卷尾(Dicrurus hottentottus)由于被认为是雌雄同态而在野外难以鉴别性别。我们研究了河南董寨国家级自然保护区79只已用分子生物学方法鉴定出性别的发冠卷尾(D.h.brevirostris)在形态量度上的性别差异,并据此构建了判别式方程,用于鉴定其性别。所考察的体征包括体重、喙长、喙粗、头喙长...  相似文献   
28.
In order to find out how small scale topographical factors affect growth and physiological characters of Caragana microphylla, which is a widely distributed shrub species and has an important role in restoring degraded grassland in natural ecosystem, a natural population of C. microphylla was chosen in a typical steppe community in June, 2009. The population was 34 km to the southeast of Xilinhot City, China, and a total of 54 shrubs were selected from different slope aspects and positions. We investigated the photosynthetic and morphological characters of these shrubs and analyzed the relationship between plant traits of C. microphylla and soil nitrogen and phosphorus availability. Moreover, the relationship between plant traits of C. microphylla and herbaceous aboveground biomass was studied. (1) The maximum net photosynthetic rate (Pnmax) was significantly lower on shady slopes than that on sunny slopes and higher on upper slopes than that on lower slopes. Stomatal conductance (Gs), net photosynthetic rate/intercellular CO2 concentration (Pn/Ci) and intercellular CO2 concentration (Ci) under saturated irradiance showed similar trends with slope aspect and position. Likewise, the maximum photochemical efficiency of PSII (Fv/Fm), PSII potential activity (Fv/Fo) and the first-year shoot morphological characters of C. microphylla were also correlated with slope aspect and position. (2) Soil nitrogen availability showed no significant effect on photosynthetic or morphological traits of C. microphylla, however, there were several significant relationships between soil phosphorus availability and plant traits. Dry weight, shoot length, compound leaf size, and leaflet length of first-year shoots of C. microphylla were significantly negatively correlated with soil C:P ratio. Though not significant, photosynthetic parameters under saturated light and other morphological characters of first-year shoots were negatively correlated with soil C:P ratio, i.e., these traits increased with increasing soil phosphorus availability. These suggested that the difference of soil phosphorus availability played an important role in making C. microphylla having different photosynthetic and morphological characters on different slope aspects and positions. The individuals grown in relatively P-rich site had longer shoots and larger leaves and grew better. Low phosphorus content was thought to limit photosynthetic activity through several different mechanisms, including both stomatal and non-stomatal limitations, the latter being more likely in the present study. (3) Photosynthetic and morphological characters of C. microphylla were all negatively correlated with herbaceous aboveground biomass, though only Pn/Ci and length of first-year shoot were significantly correlated with it. This indicated that the difference in plant community was a factor making C. microphylla have different growth and physiological characters on different aspects and positions of slope. A number of studies showed that grazing of the herbaceous layer promoted the establishment and proliferation of woody species, and then led to grassland deterioration; but in arid and semi-arid ecosystems, some widely distributed shrub species like C. microphylla created resource islands and provide favorable microhabitat for grass species. In the present study, we found negative correlations between traits of C. microphylla and herbaceous aboveground biomass. We suggested that the removal of livestock grazing result in the decrease of the distribution C. microphylla and increase of grass coverage, and lead to the restoration of the typical steppe.  相似文献   
29.
Questions: Is light availability the main factor driving forest dynamics in Pyrenean sub‐alpine forests? Do pines and firs differ in growth, mortality and morphological response to low light availability? Can differences in shade tolerance affect predictions of future biome changes in Pyrenean sub‐alpine forests in the absence of thermal limitation? Location: Montane–sub‐alpine ecotones of the Eastern Pyrenees (NE Spain). Methods: We evaluated morphological plasticity, survival and growth response of saplings of Scots pine, mountain pine and silver fir to light availability in a mixed forest ecotone. For each species, we selected 100 living and 50 dead saplings and measured size, crown morphology and light availability. A wood disk at root collar was then removed for every sapling, and models relating growth and mortality to light were obtained. Results: Fir had the lowest mortality rate (<0.1) for any given light condition. Pines had comparable responses to light availability, although in deep shade Scots pine risked higher mortality (0.35) than mountain pine (0.19). Pines and fir developed opposing strategies to light deprivation: fir employed a conservative strategy based on sacrificing height growth, whereas pines enhanced height growth to escape from shade, but at the expense of higher mortality risk. Scots pine showed higher plasticity than mountain pine for all architectural and morphological traits analysed, having higher adaptive capacity to a changing environment. Conclusions: Our results support the prediction of future biome changes in Pyrenean sub‐alpine forests as silver fir and Scots pine may find appropriate conditions for colonizing mountain pine‐dominated stands due to land‐use change‐related forest densification and climate warming‐related temperature increases, respectively.  相似文献   
30.
Allometric trends in the degree of sexual dimorphism with body size have long fascinated evolutionary biologists. Many male-biased clades display more prominent sexual dimorphism in larger taxa (Rensch's rule), with most examples documenting this pattern for body size dimorphism. Although sexual dimorphism in traits other than body size is equally functionally relevant, characterizing allometric patterns of sexual dimorphism in such traits is hampered by lack of an analytical framework that can accommodate multivariate phenotypes. In this article, we derive a multivariate equivalency for investigating trends in sexual dimorphism—relative to overall body size—across taxa and provide a generalized test to determine whether such allometric patterns correspond with Rensch's rule. For univariate linear traits such as body size, our approach yields equivalent results to those from standard procedures, but our test is also capable of detecting trends in multivariate datasets such as shape. Computer simulations reveal that the method displays appropriate statistical properties, and an empirical example in Mediterranean lizards provides the first demonstration of Rensch's rule in a multivariate phenotype (head shape). Our generalized procedure substantially extends the analytical toolkit for investigating macroevolutionary patterns of sexual dimorphism and seeking a better understanding of the processes that underlie them.  相似文献   
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