Vertical distribution of Blackcap (Sylvia atricapilla) and Garden Warbler (Sylvia borin) within the vegetation

Zusammenfassung Vertikale Verteilung von Mönchs- und Gartengrasmücken in der Vegetation. — In Norditalien ließen sich jahreszeitliche Unterschiede in der vertikalen Verteilung von Mönchsgrasmücken mit Hilfe standardisierter Netzfänge feststellen. Im Herbst kann sich aus der Ähnlichkeit des Verteilungsmusters zwischen Garten- und Mönchsgrasmücke interspezifische Konkurrenz ergeben. Die gefundenen Verteilungsmuster gleichen solchen aus Gegenden mit ganz anderer Artenzusammensetzung der Vegetation.

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Summary Vertical distribution patterns of Blackcap and Garden Warbler within homogeneous vegetation have been investigated through standardized mist-netting in Northern Italy. A clear seasonal difference in the use of the vegetation has been shown in the Blackcap. Some kind of interspecific competition can be expected on the basis of the similarity in the autumn vertical distribution of the two species; both distribution patterns are very similar to those found by other authors in areas with different plant species composition.

     

House Wrens Troglodytes aedon reduce repertoire size and change song element frequencies in response to anthropogenic noise

Anthropogenic noise (≤ 3 kHz) can affect key features of birds’ acoustic communication via two different processes: (1) song‐learning, because songbirds need to hear themselves and other birds to crystallize their song, and (2) avoidance of song elements that overlap with anthropogenic noise. In this study we tested whether anthropogenic noise reduces the number of song elements in the repertoire of House Wren Troglodytes aedon, an urban species. Additionally, we tested whether the proportion of high‐frequency elements (i.e. elements where the minimum frequency is above 3 kHz) is related to anthropogenic noise levels, and how the frequencies and duration of shared elements between males change with different levels of anthropogenic noise. We recorded 29 House Wren males exposed to different anthropogenic noise levels (36.50–79.50 dB) during two consecutive breeding seasons from four locations. We recorded each male on 2 days during each season continuously for 50 min (we collected 104 h of recordings) and measured anthropogenic noise levels every 10 min inside each male territory during the recording period. In general, individuals inhabiting noisier territories had smaller repertoires. However, only in two locations with anthropogenic noise levels between 38.60 and 79.50 dB did males inhabiting noisier territories have smaller repertoires. In the other two locations with lower anthropogenic noise (36.50–66.50 dB), the anthropogenic noise inside each territory was not related to the repertoire size. Individuals inhabiting the noisiest location showed a tendency to include more high‐frequency elements in their songs. In 26% of the elements, the anthropogenic noise affected their frequency features. Our results showed that not all House Wrens inhabiting urban environments modify their songs at the highest level of organization (i.e. repertoire) to reduce the masking effect of anthropogenic noise on acoustic communication.     

Age-related changes in song repertoire size and song type sharing in the Whinchat Saxicola rubetra

In many oscine passerines males’ songs, the repertoire size increases with age. At the same time it often remains unknown when and where males learn new songs. To infer the Whinchat Saxicola rubetra song learning strategy, we described and catalogued song-type repertoire, revealed age differences and examined song sharing strategies among neighbouring and distant males. We recorded song vocalizations of 40 males in a limited (104 ha) study plot during four years. Whinchats produce short and discrete songs with clear intersong pauses. In total 45 song types were allocated, the individual repertoire size averaged 23.5 ± 7.6 song types (range 9–34 song types). The males’ age significantly influenced the song-type repertoire size. The second calendar year (first breeding) males had a lower repertoire size than the older males. The majority of song types were shared by less than half of males in our sample. The Jaccard similarity indexes varied from 0.5 to 0.7. We could not find a relationship between males’ song sharing and geographic distances between their nests. We assume that Whinchat males learned new songs in the local population before territory establishment.     

蓖麻RcMsc2基因功能分析

G2/有丝分裂特异性细胞周期蛋白 2(G2/mitotic-specific cyclin-2,Msc2)作为高等植物应对逆境胁迫的关键调控蛋白,参与多个抗逆境胁迫的应答。为探究RcMsc2基因的功能,该研究从蓖麻叶片组织中成功克隆了RcMsc2,并利用生物信息学分析RcMsc2蛋白的结构和潜在功能,同时借助qRT-PCR方法分析RcMsc2基因的组织表达特性和非生物胁迫表达特性。结果表明:(1)RcMsc2基因位于蓖麻第5号染色体长臂,该基因的CDS(coding sequence)区是1 299 bp,编码432个氨基酸。(2)RcMsc2蛋白拥有细胞周期(cyclin)家族特征结构域,是一个不稳定酸性亲水蛋白,无跨膜域和信号肽,相对分子量为49.38 kD。(3)RcMsc2蛋白质的二级、三级结构以α-螺旋和无规则卷曲为主。(4)RcMsc2蛋白与麻风树和巴西橡胶树的CYCB2蛋白的序列同源性最高,且同被聚为Group Ⅱ。(5)35S-RcMsc2-GFP融合蛋白定位于细胞核。(6)RcMsc2基因在蓖麻的所有组织中均有表达且主要在根和茎中发挥作用; 非生物胁迫分析表明RcMsc2基因可以被脱落酸(abscisic acid, ABA)、盐、干旱和低温处理诱导表达,并且RcMsc2基因对低温胁迫的响应最敏感。综上表明,该研究较全面地分析了RcMsc2基因的结构特征、系统进化和表达模式,为揭示RcMsc2基因在蓖麻的生长发育和应答冷胁迫过程中的功能提供了理论参考。     

Territory tenure in song sparrows is related to song sharing with neighbours, but not to repertoire size

Song repertoires may be a product of sexual selection and several studies have reported correlations of repertoire size and reproductive success in male songbirds. This hypothesis and the reported correlations, however, are not sufficient to explain the observation that most species have small song repertoire sizes (usually fewer than 10, often fewer than five song types). We examined a second important aspect of a male's song repertoire, the extent to which he shares songs with his neighbours. Song sharing has not been measured in previous studies and it may be partially confounded with repertoire size. We hypothesized that in song sparrows, Melospiza melodia, song sharing rather than repertoire size per se is crucial for male territorial success. Our longitudinal study of 45 song sparrows followed from their first year on territory showed that the number of songs a bird shares with his neighbourhood group is a better predictor of lifetime territory tenure than is his repertoire size. We also found that song sharing increases with repertoire size up to but not beyond eight to nine song types, which are the most common repertoire sizes in the population (range in our sample 5-13). This partial confound of song sharing and repertoire size may account for some earlier findings of territory tenure-repertoire size correlations in this species and other species having small- or medium-sized repertoires. Copyright 2000 The Association for the Study of Animal Behaviour.     

Nestling growth and song repertoire size in great reed warblers: evidence for song learning as an indicator mechanism in mate choice

Females of many songbird species show a preference for mating with males that have larger song repertoires, but the advantages associated with this preference are uncertain. We tested the hypothesis that song complexity can serve as an indicator of male quality because the development of the brain regions underlying song learning and production occurs when young birds typically face nutritional and other stresses, so that song reflects how well a male fared during post-hatch development. A key prediction of this hypothesis is that variation in nestling condition should correspond to variation in the adult song repertoires of individuals. We used data from a long-term study of the great reed warbler (Acrocephalus arundinaceus) to test this prediction, correlating two measures of nestling development with subsequent repertoire size of males. We found that the length of the innermost primary feather, a standard measure of development, significantly predicted first-year repertoire size. The relationship between repertoire size and body mass was nearly significant, in spite of the large variance inherent in this measure. These data support the idea that song may provide females with information about a male's response to developmental stress, which in turn is expected to correlate with indirect or direct benefits she might receive.     

芦苇浸提液对虉草种子萌发及幼苗生长生理特性的影响

通过研究不同浓度芦苇浸提液(对照:0;处理1:150g/L;处理2:300g/L)对虉草萌发及幼苗生长影响,揭示了芦苇对虉草化感效应。结果表明:随着芦苇浸提液浓度升高,虉草发芽率、发芽指数、株高、根长以及叶绿素含量显著或极显著下降,各指标相应化感效应指数则显著或极显著上升;超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性和丙二醛(MDA)含量则随芦苇浸提液浓度升高呈不同的升降趋势。所有这些结果显示,随着浸提液浓度升高,芦苇对虉草的化感胁迫效应越来越明显。     

Role of gene regulation in song circuit development and song learning

The songbird has emerged as an important model for study of brain-behavior relationships by virtue of its rich natural advantages and from the pioneering efforts of explorers using anatomical and behavioral approaches. Now, molecular biology is providing a new and complementary paradigm for discerning songbird brain organization and function. Here, I review the work over the last 10 years that has laid the foundation for approaching songbird biology from the molecular perspective. As a result of this work, specific hypotheses can now be framed and tested regarding the mechanisms behind song circuit formation, behavioral plasticity, and the boundaries of adaptability. Age-related changes in more than 15 molecules have been observed in the song system of juvenile zebra finches, and these changes seem to define specific phases in circuit development. In adult songbirds, ordinary song-related activities such as singing and listening cause dramatic increases in gene expression in brain areas specific to each activity. The sensitivity of gene activation is modulated as a result of experience in adulthood and also changes during juvenile song learning. These studies have provided unexpected insights into the functional organization of the song circuit and the potential role of extrinsic modulatory systems in directing and limiting plastic change in the brain. With this rich base of knowledge, and techniques of gene manipulation on the horizon, answers to old questions seem within our reach: What sets the boundaries of neural plasticity? What limits learning? © 1997 John Wiley & Sons, Inc. J Neurobiol 33: 549–571, 1997     

Genetic differentiation of two distinct chemotypes of Ferula communis (Apiaceae) in Sardinia (Italy)

The giant fennel, Ferula communis L. (Apiaceae) is a circum-Mediterranean species responsible of severe haemorrhagic intoxication of livestock. Electrophoretic analysis of 14 putative enzyme loci was carried out to assess genetic differentiation among poisonous and non-poisonous chemotypes of F. communis in Sardinia. Genetic structuring characterises all the five populations examined. However, differentiation was higher between poisonous and non-poisonous populations (P<0.00001), and was independent from geographic distances, suggesting a reduced gene flow between the two chemotypes.     

No overlap in song repertoire size between yearling and older Starlings Sturnus vulgaris

We recorded the song of 25 male Starlings Sturnus vulgaris to investigate differences in song characteristics between yearling and older males. Older males had significantly larger repertoire sizes and sang significantly longer average song bouts than yearling males. Since older males had almost twice as large a repertoire size as yearling males and since there was no overlap in repertoire size between yearling and older males, our data indicate that the repertoire size of Starlings increases after the first year of life. The largest difference between yearling and older males occurred in the 'variable song types' which are the song types containing most of the heterospecific imitations sung in a song bout.     

EGTA和酒石酸对蓖麻Cd胁迫与积累的调控作用

通过盆栽试验研究了解毒剂酒石酸与螯合剂EGTA的单施与配施对强化蓖麻修复Cd污染土壤的作用,探讨重金属污染土壤植物修复中螯合剂与解毒剂配合使用的可行性。结果显示:(1)除酒石酸单施处理外,其余处理均可显著提高土壤中醋酸提取态Cd含量,增强土壤Cd的活性,并以酒石酸与EGTA配施的效果更显好,其土壤醋酸提取态Cd含量为对照的1.41~2.49倍。(2)EGTA能有效促进Cd从蓖麻根部向地上部的转移,但高剂量EGTA处理对蓖麻根系有明显的毒害作用;EGTA与酒石酸配合施能缓解Cd对植株的毒害作用,增大蓖麻生物量和Cd积累量,其地上部Cd积累量比对照增加4.56~8.32倍。(3)蓖麻叶片Cd含量、地上部积累总量以及土壤净化率随土壤醋酸提取态Cd含量的升高而增大,并且呈良好的线性递增关系。研究表明,酒石酸与EGTA配施可通过调控土壤Cd的植物可利用性和降低Cd的生理毒性来提高蓖麻对Cd的富集能力和对Cd污染土壤的修复效果。     

Song duration mediates responses of territory owner in a songbird species with a small song repertoire

Song is a sexually selected trait that is involved in mate attraction and territory defence in birds. Songs may convey information about different male quality components. They are flexible in terms of frequency, amplitude, and duration. Although changes in song duration are common, the function of this behaviour has been studied less strongly. It is known that song duration changes within a singing bout and may provide information about aggressive motivation. We tested whether the elongation and shortening of songs affects the responses of territorial ortolan bunting males to neighbour song playback. If changing song duration signals level of aggressiveness, then songs differing solely in duration may elicit behavioural responses of different strength. We performed two tests with different males assigned to two experimental groups and measured approaching and vocal response. In Experiment 1, we tested 18 males, which responded to the playbacks of elongated and normal (control) neighbour songs. In Experiment 2, we tested 17 males, which responded to the playbacks of shortened and normal (control) neighbour songs. Males responded significantly stronger to longer songs in both experiments as measured by the approach variable. Vocal response was not affected by treatment, but it was affected by the order of playback presentation. Our results indicate that song duration might be used for signalling current aggressive motivation during close interactions with rivals.     

The development and geometry of shape change in Arabidopsis thaliana cotyledon pavement cells

Background  

The leaf epidermis is an important architectural control element that influences the growth properties of underlying tissues and the overall form of the organ. In dicots, interdigitated pavement cells are the building blocks of the tissue, and their morphogenesis includes the assembly of specialized cell walls that surround the apical, basal, and lateral (anticlinal) cell surfaces. The microtubule and actin cytoskeletons are highly polarized along the cortex of the anticlinal wall; however, the relationships between these arrays and cell morphogenesis are unclear.     

Coal TitParus ater song repertoires and the Beau Geste hypothesis

At least 44 different song types were recorded in a population of Coal Tits at Klaebu in central Norway. Each male sang up to 14 different types. In testing the Beau Geste hypothesis the following predictions were made: (1) Territorial males tend to change song type when moving from one song post to another. (2) The tendency to change song type when moving from one song post to another increases with the distance between the song posts. (3) Territory holders prefer inconspicuous song posts that reduce the chances of being instantly detected by possible intruders and prospectors. However, none of these predictions were confirmed by the data analyses. The singing behaviour of the Coal Tit does therefore not support the Beau Geste hypothesis.

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Zusammenfassung In einer Population der Tannenmeise bei Klaebu, Mittelnorwegen, wurden mindestens 44 unterschiedliche Gesangstypen registriert. Einzelne Männchen sangen bis zu 14 Typen. Um die Beau-Geste-Hypothese (ein Sänger täuscht durch verschiedenen Gesangstypen die Anwesenheit mehrerer Individuen vor) zu testen, wurden folgende Annahmen geprüft: (1) Territoriale Männchen neigen dazu, ihren Gesangstyp zu ändern, wenn sie die Singwarte wechseln. (2) Die Tendenz, zwischen Gesangstypen zu wechseln, ist bei Männchen am größten, die während einer Gesangsphase mehr als eine Singwarte benutzen. (3) Territoriale Männchen benützen unauffällige Singwarten, um nicht so schnell von möglichen Eindringlingen oder reviersuchenden Artgenossen entdeckt zu werden. Die Analyse der Daten ergab jedoch für keine dieser Annahmen eine Bestätigung. Somit unterstützt das Verhalten singender Tannenmeisen die Hypothese nicht.

     

Phase change in loblolly pine:Shoot development as a function of age

The growth behavior of grafted scions from 1-, 4-, 8- and 12-year-old ortets representing five half-sib loblolly pine families was observed over a two-year period (three for strobilus production) following grafting. Significant, persistent decreases in total number of cycles produced, height and diameter increment, number of branches produced, foliar surface area and total scion biomass were observed with increasing age. Needle length, diameter, and ability to form male and female strobili increased with increasing scion age. The persistence of these differences is not a function of size since the scions were the same length at grafting. The significance of these results to the establishment of breeding orchards, early genetic evaluation, and the nature of phase change is discussed.     

Changes in Ricinus communis lectin binding to the cell surface of human liver cells in culture : The relationship between in vitro cellular aging and the age of the donor

Ricinus communis lectin RCA I-binding sites on the surface of cultured human liver cells have been studied with a view to establishing a relationship between the aging of the cells in vitro and the age of the donors. Fetal and new-born liver cells exhibited two classes of lectin-binding sites in the early in vitro passages, whereas adult cells in the early passages and fetal and new-born cells in the late passages had only one class of binding site. The modifications of the cell surface RCA I-binding sites would appear to occur either following masking of one of the classes of lectin-binding site during aging and/or be caused by a post-translational event rather than by glycoprotein mis-synthesis. A striking relationship was found between the in vitro cellular aging and human age in vivo, which would suggest that fetal human liver cells could prove to be a convenient model for studying the changes occurring during aging in vivo.