Current issues in fish welfare

Human beings may affect the welfare of fish through fisheries, aquaculture and a number of other activities. There is no agreement on just how to weigh the concern for welfare of fish against the human interests involved, but ethical frameworks exist that suggest how this might be approached. Different definitions of animal welfare focus on an animal's condition, on its subjective experience of that condition and/or on whether it can lead a natural life. These provide different, legitimate, perspectives, but the approach taken in this paper is to focus on welfare as the absence of suffering. An unresolved and controversial issue in discussions about animal welfare is whether non‐human animals exposed to adverse experiences such as physical injury or confinement experience what humans would call suffering. The neocortex, which in humans is an important part of the neural mechanism that generates the subjective experience of suffering, is lacking in fish and non‐mammalian animals, and it has been argued that its absence in fish indicates that fish cannot suffer. A strong alternative view, however, is that complex animals with sophisticated behaviour, such as fish, probably have the capacity for suffering, though this may be different in degree and kind from the human experience of this state. Recent empirical studies support this view and show that painful stimuli are, at least, strongly aversive to fish. Consequently, injury or experience of other harmful conditions is a cause for concern in terms of welfare of individual fish. There is also growing evidence that fish can experience fear‐like states and that they avoid situations in which they have experienced adverse conditions. Human activities that potentially compromise fish welfare include anthropogenic changes to the environment, commercial fisheries, recreational angling, aquaculture, ornamental fish keeping and scientific research. The resulting harm to fish welfare is a cost that must be minimized and weighed against the benefits of the activity concerned. Wild fish naturally experience a variety of adverse conditions, from attack by predators or conspecifics to starvation or exposure to poor environmental conditions. This does not make it acceptable for humans to impose such conditions on fish, but it does suggest that fish will have mechanisms to cope with these conditions and reminds us that pain responses are in some cases adaptive (for example, suppressing feeding when injured). In common with all vertebrates, fish respond to environmental challenges with a series of adaptive neuro‐endocrine adjustments that are collectively termed the stress response. These in turn induce reversible metabolic and behavioural changes that make the fish better able to overcome or avoid the challenge and are undoubtedly beneficial, in the short‐term at least. In contrast, prolonged activation of the stress response is damaging and leads to immuno‐suppression, reduced growth and reproductive dysfunction. Indicators associated with the response to chronic stress (physiological endpoints, disease status and behaviour) provide a potential source of information on the welfare status of a fish. The most reliable assessment of well‐being will be obtained by examining a range of informative measures and statistical techniques are available that enable several such measures to be combined objectively. A growing body of evidence tells us that many human activities can harm fish welfare, but that the effects depend on the species and life‐history stage concerned and are also context‐dependent. For example, in aquaculture, adverse effects related to stocking density may be eliminated if good water quality is maintained. At low densities, bad water quality may be less likely to arise whereas social interactions may cause greater welfare problems. A number of key differences between fish and birds and mammals have important implications for their welfare. Fish do not need to fuel a high body temperature, so the effects of food deprivation on welfare are not so marked. For species that live naturally in large shoals, low rather than high densities may be harmful. On the other hand, fish are in intimate contact with their environment through the huge surface area of their gills, so they are vulnerable to poor water quality and water borne pollutants. Extrapolation between taxa is dangerous and general frameworks for ensuring welfare in other vertebrate animals need to be modified before they can be usefully applied to fish. The scientific study of fish welfare is at an early stage compared with work on other vertebrates and a great deal of what we need to know is yet to be discovered. It is clearly the case that fish, though different from birds and mammals, however, are sophisticated animals, far removed from unfeeling creatures with a 15 s memory of popular misconception. A heightened appreciation of these points in those who exploit fish and in those who seek to protect them would go a long way towards improving fish welfare.     

庐山野生观赏植物资源多样性及持续利用对策

庐山是我国著名的风景旅游和避暑胜地,也是我国中亚热带北缘植物多样性的宝库．本文在广泛调查、收集、整理的基础上,研究了庐山野生观赏植物资源多样性特征、分布、类型及其配置．本区分布有野生观赏植物５２８种,隶属于１１５科２９０属,其中乔木类１３８种,灌木类１４０种,藤木类５２种,草本类１９８种．并根据开发与保护现状对庐山野生观赏植物资源多样性的持续利用提出了切实可行的对策．     

A contaminant,Erwinia carotovora,affecting commercial plant tissue cultures

Summary Commercial plant tissue cultures of several ornamental plants exhibiting reduced vigor and chlorosis in stage II were found to contain bacterial contaminants. In most cases, visible evidence of the contaminants in the tissue-culture medium was not easily discernible. Physiological and pathological tests employing pure cultures proved 5 of the 10 isolates obtained to beErwinia carotovora, an important pathogen of many horticultural plants. The tissue cultures from whichE. carotovora was isolated were of plant types nonsusceptible under normal commercial production methods. These results indicate nonhost plants may serve as carriers ofE. carotovora during tissue-culture propagation and also possibly under normal methods of commercial production. Florida Agricultural Experiment Stations Journal Series No. 883. This investigation was supported in part by The Fred C. Gloeckner Foundation.     

遮荫对彩叶植物矾根夏季适应性表型的影响

以彩叶植物矾根(Heuchera micrantha)‘蜜桃’(‘Georgia Peach’)、‘小珍珠’(‘Petite pearl fairy’)、‘花毯’ (‘Tapestry’)为材料,研究不同遮荫处理对矾根观赏特征、高温半致死温度以及成活率的影响。结果表明,在遮荫条件下,三个矾根品种株高增加、叶面积变大、花序变长、开花推迟,‘蜜桃’和‘小珍珠’花期延长,‘花毯’花期缩短。遮荫引起‘蜜桃’和‘小珍珠’叶绿素含量、类胡萝卜素含量显著上升,花色素苷含量明显下降,叶色由红、紫色向灰绿色转变,叶片彩化度下降;‘花毯’的叶绿素、类胡萝卜素和花青素含量均随遮荫度增加显著上升,其叶色由浅绿转为深绿,叶脉紫红色加重,彩化度提高,观赏性增强。随着遮荫度提高,三个矾根品种的高温半致死温度明显升高,成活率显著上升。相关性分析表明,三个矾根品种的成活率与最高气温、最大光强、气温、光强分别存在极显著负相关关系,与相对湿度以及该品种的高温半致死温度分别存在极显著正相关关系。多元逐步回归分析表明,高光强是引起‘蜜桃’成活率下降的关键因素,‘小珍珠’的成活率主要取决于高温半致死温度,‘花毯’的成活率主要受极端高温的影响。     

In vitro micropropagation of Dracaena sanderiana Sander ex Mast: An important indoor ornamental plant

A protocol has been developed for in vitro plant regeneration from a nodal explant of Dracaena sanderiana Sander ex Mast. Nodal explant showed high callus induction potentiality on MS medium supplemented with 6.78 μM 2,4-dichlorophenoxyacetic acid (2,4-D) followed by 46.5 μM chlorophenoxy acetic acid (CPA). The highest frequency of shoot regeneration (85%) and number of shoots per explant (5.6) were obtained on medium supplemented with 7.84 μM N⁶-benzylaminopurine (BA). Rooting was high on MS solid compared to liquid medium when added with 7.38 μM indole-3-butyric acid (IBA). Fifty percent of the roots were also directly rooted as microcuttings on soil rite, sand and peat mixture (1:1:1). In vitro and ex vitro raised plantlets were used for acclimatization. More than 90% of the plantlets was successfully acclimatized and established in plastic pots. Ex vitro transferred plantlets were normal without any phenotypic aberrations.     

Rapid and repeatable host plant shifts drive reproductive isolation following a recent human-mediated introduction of the apple maggot fly,Rhagoletis pomonella

Ecological speciation via host-shifting is often invoked as a mechanism for insect diversification, but the relative importance of this process is poorly understood. The shift of Rhagoletis pomonella in the 1850s from the native downy hawthorn, Crataegus mollis, to introduced apple, Malus pumila, is a classic example of sympatric host race formation, a hypothesized early stage of ecological speciation. The accidental human-mediated introduction of R. pomonella into the Pacific Northwest (PNW) in the late 1970s allows us to investigate how novel ecological opportunities may trigger divergent adaptation and host race formation on a rapid timescale. Since the introduction, the fly has spread in the PNW, where in addition to apple, it now infests native black hawthorn, Crataegus douglasii, and introduced ornamental hawthorn, Crataegus monogyna. We use this “natural experiment” to test for genetic differentiation among apple, black, and ornamental hawthorn flies co-occurring at three sympatric sites. We report evidence that populations of all three host-associations are genetically differentiated at the local level, indicating that partial reproductive isolation has evolved in this novel habitat. Our results suggest that conditions suitable for initiating host-associated divergence may be common in nature, allowing for the rapid evolution of new host races when ecological opportunity arises.     

Characterisation of Pectobacterium carotovorum causing soft rot on Kalanchoe gastonis-bonnierii in Malaysia

Soft rot disease can be found worldwide on fleshy storage tissues of fruits, vegetables and ornamentals. The soft rot Pectobacterium carotovorum subsp. carotovorum (Pcc) is an important pathogen of Kalanchoe spp. and other ornamental plants. The disease occurs on crops in the field, greenhouses and during transit, resulting great economic damages. The economic importance of crop loss by soft rot bacteria varies by severity of the disease and value of the crop. A destructive disease on Kalanchoe gastonis-bonnierii was observed in commercial ornamental plant greenhouses in Cameron highland and Melaka, Malaysia in 2011. Samples suspected to be infested with Pectobacterium spp. were brought to the laboratory. In pathogenicity test, a suspension of 10^6?CFU/ml of strains was able to cause soft rot on leaves and stems. A 434?bp banding pattern on 1% agarose gel was produced in polymerase chain reaction (PCR) amplification of pectate lyase encoding gene (Pel gene). PCR amplification of the intergenic transcribed spacer (ITS) (16S–23S rRNA) ITS region with G₁ and L₁ primers produced two main bands at about 540 and 570?bp. The ITS-PCR products were digested with RsaI restriction enzyme. For discrimination of the P. carotovorum subsp. carotovorum (Pcc) from P. carotovorum subsp. odoriferum (Pco), all isolates subjected to α-methyl glucoside test. All isolates were identified as Pcc based on phenotypic and molecular methods. This is the first report of soft rot disease caused by P. carotovorum subsp. carotovorum on K. gastonis-bonnierii, in Malaysia.     

观赏向日葵八氢番茄红素脱氢酶基因PDS的cDNA克隆与表达特性分析

采用RT-PCR和RACE技术从观赏向目葵‘闽葵3号’黄色花瓣中克隆到类胡萝卜素合成途径关键基因HaPDS的cDNA,该cDNA全长2017bp,具有一个1710bp的完整开放阅读框（ORF）,编码一个570个氨基酸的蛋白质。序列分析表明,HaPDS编码的氨基酸序列与其他植物的PDs蛋白具有很高的同源性,在N-端有一个辅助因子结合结构域,C-端有一个类胡萝卜素结合域。系统进化树分析显示,观赏向日葵HaPDS与万寿菊、菊花蛋白亲缘关系较近。实时荧光定量RT-PCR技术分析表明,胁肋路因在花发育的盛花期表达量最高;不同组织中的表达量舌状花瓣〉苞片〉叶片〉绿色管状花〉黑色管状花：随着基因表达量的增加,花色由白色到黄色、金黄色转变。     

遮光处理对观赏栀子氮、磷、钾分配与生长的影响

为探究观赏栀子在不同遮光条件下生长和光合及氮、磷、钾(N、P、K)分配的规律,该研究对3种观赏栀子设置5种不同的遮光处理(0%、60%、70%、80%、90%),通过对观赏栀子的生长和光合及各器官N、P、K含量进行统计与分析,探究了不同遮光处理对观赏栀子栽植效果的影响。结果表明:(1)60%和0%遮光率的大花栀子、80%和70%遮光率的雀舌栀子、0%遮光率的花叶栀子均长势较好。(2)随着遮光率的增加,雀舌栀子和花叶栀子的净光合速率、胞间CO₂浓度、蒸腾速率逐渐降低,气孔导度、水分瞬时利用率在遮光率60%下达到最大值。(3)大花栀子总N量最高,器官含N量高低排序为叶、根、茎; 雀舌栀子总P量最高,器官含P量排序为根、茎、叶; 大花栀子在90%遮光率下含K量最高。综合考虑认为,雀舌栀子更耐荫蔽,适合在80%和70%的遮光条件下生长; 大花栀子次之,适合在60%和0%遮光条件下生长; 花叶栀子最不耐荫,适合在0%遮光条件下生长。