黑河下游绿洲胡杨生长状况与叶生态特征

选择黑河下游额济纳绿洲为研究区,以优势物种胡杨(Populus euphratica Oliv.)为研究对象。在2009年和2010年对研究区胡杨的生长状况、叶生态特征和生境进行了调查。调查结果表明:胡杨受水分胁迫的程度增强,生长态势变差,其枯枝比由2.45%增加到81.00%,其比叶面积由11.84 m2/kg减少到5.35 m2/kg。叶气孔密度变化很大,最小值为105(个/mm2),最大值为218(个/mm2),平均值为158.4(个/mm2),随着地下水埋深的增加,叶气孔密度先减少后增加之后再显著减少(P0.05),呈三次函数关系。研究得出枯枝比能够反映胡杨分布区地下水的变化状况,是林相描述比较重要的指标,比叶面积和叶气孔密度能够指示胡杨种群环境变化。研究结果可为荒漠河岸林恢复和生态输水效应评价提供科学依据。     

云南红豆杉人工林萌枝特性

萌枝是许多木本植物维持种群稳定和延续的重要机制之一。本文通过对云南红豆杉人工林萌枝情况的调查,分析了云南红豆杉萌枝特征及其对生长的影响。结果表明：（1）云南红豆杉萌枝现象明显,萌枝率达到88.1%,萌枝类型有树基萌枝和树干萌枝两种,其中树基萌枝是最主要的类型,有树基萌枝的个体达到了总株数的80.0%,树干萌枝率仅为39.6%,约为树基萌枝率的一半,两种萌枝都有的比率为31.5%;（2）云南红豆杉的树基萌枝数量与树高呈正相关关系,与地径呈负相关关系,而树干萌枝数量与树高和地径都没有显著的相关关系。总萌枝数量与树高及地径的相关关系与树基萌枝的一样,但相关性略低。（3）树基萌枝和树干萌枝都会影响云南红豆杉枝叶的空间分布格局,但从植株总体上说,它们对云南红豆杉的枝叶生长量没有显著的影响。     

云南元江普通野生稻穗颈维管束和穗部性状的QTL分析

以云南元江普通野生稻为供体亲本,籼稻品种特青为轮回亲本构建高代回交群体,用SSR标记构建连锁图谱,在第1、2、3、4、7和10染色体上定位到7个控制穗颈大维管束数的QTL,在第1、2、3、4和8染色体上定位到5个控制穗颈小维管束数的QTL,在第11和12以外的10条染色体上,共定位到15个控制穗一、二次枝梗数和穗颖花数QTL。来自野生稻的等位基因大多表现负效,能显著减少群体的穗颈维管束数、枝梗数和颖花数,说明从野生稻演化成栽培稻的过程中,可能淘汰了一些对产量不利的QTL,保留了有利的QTL。相当一部分控制穗颈维管束数、枝梗数及颖花数的QTL在染色体上成簇分布或紧密连锁,且加性效应的方向一致,从理论上解释了这些性状表型显著相关的遗传基础,同时也说明在人工选择或自然选择下,这些性状可能存在平行进化或协同进化的关系。     

药剂输液滴干对龙眼成花的影响

虹吸输液滴干技术作为一种新型的输液技术,能显著提高龙眼对调节剂的利用率。该研究利用虹吸输液滴干技术来研究氯酸钾与多效唑对龙眼成花的影响,同时探索从花芽生理分化期开始控制龙眼冲梢的方法。结果表明：氯酸钾输液滴干不但能够促使龙眼提早开花,而且能够提高其成花率、抽穗率、雌雄花比例与坐果率。不同品种龙眼对氯酸钾的敏感度不同,‘石硖’对氯酸钾最为敏感,但稳定性低;‘储良’对氯酸钾的敏感性低,但稳定度高;‘桂香’对氯酸钾的敏感性与稳定度居中。从整体上看,‘石硖’的处理效果最好,最佳处理次数为3次,每次施用7.5 L浓度为1 g·L-1的氯酸钾,处理后枝梢成花率、枝梢抽穗率、雌雄花比例、坐果率分别为53.67％、59.38％、16.01和19.58％。多效唑输液滴干对‘桂龙1号’的控梢效果显著,有效促进了龙眼成花,并以160 mg·L-1的多效唑溶液处理效果最佳,抽梢率为15.16％,抽穗率、雌花率、花穗长、花穗宽和坐果率分别为96.53％、10.36％、21.95 cm、12.96 cm和38.37％。药剂输液滴干技术施用氯酸钾和多效唑对于龙眼成花坐果有积极作用,该研究结果为实现高效、省工、环保的果园管理模式提供了借鉴。     

The influence of large mammalian herbivores on growth form and utilization of mopane trees, Colophospermum mopane, in Botswana's Northern Tuli Game Reserve

Mopane veld is of great value to the general ungulate spectrum in times of drought, and it is capable of retaining its dominance in a community even in the presence of extremely heavy browsing pressure imposed by large browsing mammals. Scrub mopane (hedges) has been regarded as resulting from excessive browsing pressure by large mammals, especially elephants. Both the nutrient and chemical composition of mopane twig bark were investigated, the seasonal results being related back to the seasonal utilization of branches by large mammals. Mopane twigs were most palatable in winter. Eland feed on mopane throughout the year irrespective of palatability. Elephants were rarely present in the scrub mopane area before the onset of spring rains, when the major mopane leaf flush occurs independently of rainfall. The impact of both species was not excessive and recruitment of mopane seedlings does occur. Herbivore browsing is responsible for a mopane morph which buds early and continues to produce accessible, nutritious leaves even when heavily browsed. Many browsing ungulates are reliant on this resource during the stressful transition from spring to summer in south-eastern Botswana.     

The occurrence of myxomycetes in wood

Although the fruiting bodies of myxomycetes are commonly found associated with coarse woody debris in forest ecosystems throughout the world, there is no direct evidence that these organisms actually live within wood. In the research reported herein, surface sterilisation of pieces of wood taken from the branches of eight different tree species and the subsequent culturing of slivers of wood collected from within the interior of those branches clearly revealed the presence of the amoeboflagellates of myxomycetes. No evidence of the occurrence of plasmodia within wood was found, but amoeboflagellates emerged from 47 % of the wood slivers placed in culture.     

Behavioural studies on the peppered moth Biston betularia and a discussion of the role of pollution and lichens in industrial melanism

We examined the resting behaviour during pairing and egg-laying of bred female Biston betularia (L.) after they were set free at wooded sites in Somerset and Cardiff. Moths were not released immediately on emergence but were held for three nights to overcome an initial period of flight activity. Females (N= 257) were placed on trunks, and on large and small branches of trees, especially oaks, over periods of several weeks in 1984, 1985 and 1986. Releases were not made within 50 m of any known survivor. One hundred and thirty-one pairings were observed. We also examined oviposition behaviour in a cage experiment using different types of branches. Our observations support Mikkola's earlier conclusion from cage experiments with male moths that the species rests predominantly on branches and shows an appropriately specialized resting attitude, demonstrated here in a series of photographs. Many moths will rest underneath, or on the side of, narrow branches in the canopy. Once released females had settled and paired they only moved quite short distances, but positioning and egg-laying were profoundly influenced by the presence of foliose lichens. Females of all phenotypes show a strong preference to oviposit beneath a thallus of foliose lichens. Their tendency to rest against or close to the lichen during the day could markedly influence their crypsis. In the absence of foliose lichens, eggs are laid in cracks in the bark. The survivorship of released females both in different pairing combinations and during their whole reproductive life-span is analysed. These preliminary data suggest that bird predation can give rise to differential mortality of different pairing combinations and of the phenotypes. This technique provides a powerful method of measuring the relative crypsis and differential mortality of phenotypes with living females in natural resting sites. The significance of our observations on resting behaviour is discussed with regard to the role of air pollution and epiphytes in industrial melanism. Particular attention is given to the causal mechanisms underlying recent declines in the frequency of carbonaria melanics in parts of Britain. One important factor is the new growth made by trees since the marked reduction in particulate air pollution in the 1960s. It is emphasized that we need to know much more about the interactions between pollution, epiphytes and resting backgrounds, especially in the canopy, before we can be confident of our understanding of the evolution of industrial melanism.     

水分浸泡过夜对刺槐枝条最大水分导度测定的影响及年龄差异

枝条最大水分导度是植物水分生理学研究中的核心指标之一，冲洗法是当前用来测定该指标最常用的方法，但在实验测定之前首先必须要找到获得稳定的最大水分导度的可靠方法。本研究中，我们以刺槐（Robinia pseudoacacia L.）不同年龄枝条为实验材料，通过枝条采集后立即用于实验测定和枝条经超纯水中浸泡过夜后再用于实验这两种不同处理方式对不同年龄枝条最大水分导度测定的影响，检测两种处理方式中枝条最大水分导度随冲洗时间的延长是否保持恒定来判断最大水分导度测定值的可靠性，探讨提高枝条最大水分导度测定结果稳定性的有效方法。结果显示：①未浸泡过夜的当年生枝条，经150 kPa压力冲洗达到最大导水率后，继续延长冲洗时间枝条导水率会呈近线性下降，而经超纯水浸泡过夜的当年生枝条以同样实验方法达到最大导水率后，继续延长冲洗时间枝条的导水率基本保持稳定。②二年生枝条无论是否经超纯水浸泡过夜处理，经150 kPa压力冲洗达到最大导水率后枝条的导水率都基本保持稳定，但经超纯水浸泡过夜后，二年生枝条达到最大导水率所需的冲洗时间明显比未浸泡处理短。③根据茎横截面上木质部面积所占百分比和枝条木质密度判断，实验期间当年生枝条的木质化程度明显比二年生枝条低。我们推测未经浸泡过夜的当年生枝条出现木质部水分导度随冲洗时间延长而下降是由于枝条遭受机械性损伤后产生的分泌物在冲洗过程中被引入导管堵塞导管腔所致，而超纯水浸泡枝条过夜可有效降低分泌物被引入导管的可能性。因此，我们认为超纯水浸泡枝条过夜，可提高枝条最大水分导度测定结果的稳定性。     

Cycad cone and angiosperm floral volatiles: Inferences for the evolution of insect pollination

The chemistry of the volatile emissions of male cones of four putatively insect-pollinated cycad (Cycadales) species and cones of both sexes of one wind-pollinated cycad species was analysed using GC-MS Zamia furfuracea, Macrozamia moorei, and Encephalartos altensteinii had blends consisting primarily of monoterpenoids, benzenoids, and in two causes, a di-unsaturated aliphatic hydrocarbon, while that of Zamia pumila was dominated by methyl salicylate, with sesquiterpenes and aliphatic hydrocarbons also present. In contrast, the wind-pollinated Cycas rumphii contained a series of highly alcohols, ketones and esters. The compounds classes found in the cycads are potent herbivore deterrents, and there is no apparent difference in this regard between insect- and wind-pollinated species. The results suggest convergent evolution in the gymnospermous cycads and magnoliid angiosperms of the olfactory cues that attract pollinating insects; the data are consistent with the hypothesis that early chemical attractants for pollinators evolved from herbivore deterrents.     

Virologica Sinica

正Aims and Scope Virologica Sinica is an international journal which aims at presenting the cutting-edge basic and applied research on viruses all over the world.The journal publishes peer-reviewed original research articles and reviews,which concern the latest developments in all branches of virology,including the research on the viruses of animals,