福州实蝇监测初报

自2005年5月29日至2006年5月28日在福州金山福建农林大学校园内进行了实蝇监测。采用甲基丁香酚(M e)、诱蝇酮(Cue)和地中海实蝇诱芯(T),诱集到橘小实蝇[Bactrocera(Bactrocera)dorsalis]、瓜实蝇[B.(Zeugodacus)cucurbi-tae]、南瓜实蝇[B.(Zeugodacus)tau]和具条实蝇(B.scutellata)4种实蝇,但未诱到地中海实蝇(Ceratitis capitata)。其中,橘小实蝇诱集量最大,8月中下旬达到高峰。本研究为掌握福州地区实蝇发生动态提供了基础资料。     

李产区橘小实蝇转移为害规律研究

[目的]明确橘小实蝇Bactrocera dorsarlis(Hendel)在李产区不同寄主间的转移为害规律,为制定控制其种群的策略和防治技术提供参考和依据.[方法]选择广西李主产区,调查橘小实蝇潜在寄主种类、潜在寄主果实成熟期、寄主受害率及橘小实蝇成虫在各寄主上的转移为害规律,采用Pearson相关性分析与主成分分析方法分析影响橘小实蝇发生的气象因子.[结果]李产区不同月份成熟的11种瓜果中,李受害率最为严重,最高达22％,枇杷、酸梅、黄皮、沙糖橘、皇帝柑、柚和柿可作为橘小实蝇的潜在寄主;橘小实蝇的转移为害规律为枇杷(4月)→三月李、三华李、酸梅和黄皮(5-8月)→沙糖橘、皇帝柑、柚和柿(9-10月)→柿(11月);李产区橘小实蝇始见日和终见日分别为4月26日和12月22日,全年共有2个成虫发生高峰期,分别为7月上中旬和9月中下旬,其发生规律与气温显著相关.[结论]明确了李产区橘小实蝇的转移为害规律及其与气象因子的相关性,建议李产区应在4月份集中防治枇杷上的橘小实蝇有利于减轻对李的危害.     

橘小实蝇和番石榴实蝇卵的提取物对两种实蝇行为的影响及化学成分分析

[目的]探究橘小实蝇Bactrocera dorsalis和番石榴实蝇Bactrocera correcta卵提取物对2种实蝇雌虫行为的影响,以及2种实蝇卵表面化合物的差异,为2种实蝇的化学生态防治提供理论依据.[方法]利用Y型嗅觉仪测定了橘小实蝇交配雌虫和番石榴实蝇交配雌虫对卵表提取物的行为反应,并利用EthoVision XT软件分析雌虫在Y管内的运动轨迹;利用气相色谱-质谱联用仪(GC-MS)鉴定分析橘小实蝇卵和番石榴实蝇卵的化合物成分,并利用标准曲线法测定了各组分的含量.[结果]橘小实蝇卵提取物对橘小实蝇交配雌虫具有显著引诱作用(x2=9.383,P=-0.002),对番石榴实蝇交配雌虫具有显著驱避作用(x2=6.737,P=0.009),番石榴实蝇卵提取物对番石榴实蝇交配雌虫(x2=4.235,P=0.040)和橘小实蝇交配雌虫都具有引诱作用(x2=5.818,P=0.016).从橘小实蝇卵表提取物中共鉴定出11种化合物,分别是茴香脑、十五烷、十二烷酸、十二酸乙酯、(Z)-11-十四碳烯酸、十四烷酸、十四酸乙酯、(E)-9-十六碳烯酸乙酯、十六烷酸、十八碳烯酸、(Z)-9-十八碳烯酸乙酯.从番石榴实蝇卵表提取物中仅鉴定出7种化合物,而且这7种化合物在橘小实蝇的卵提取物中都存在.仅存在于橘小实蝇卵表的4种化合物是茴香脑、十二烷酸、十二酸乙酯、(Z)-11-十四碳烯酸.在2种实蝇卵提取物的相同成分中,十四烷酸、(E)-9-十六碳烯酸乙酯、十六烷酸在橘小实蝇卵表的含量显著高于番石榴实蝇.[结论]番石榴实蝇具有通过卵表化合物识别同种卵和异种卵的能力,2种实蝇的卵表化合物具有明显的差异.     

应用寄生蜂和不育雄虫防控田间橘小实蝇

食品安全已成为当今社会广受关注的问题。尽管国内的一些学者就阿里山潜蝇茧蜂[Fopius arisanus(Sonan)]和橘小实蝇SIT技术分别开展了不同程度的研究,然而关于应用该蜂和不育雄虫对橘小实蝇[Bactrocera dorsalis(Hendel)]进行田间联合防治的研究还未见相关报道。为此,为探讨天敌昆虫和雄性不育技术对橘小实蝇的田间综合治理(IPM)技术,开展了阿里山潜蝇茧蜂和橘小实蝇不育雄虫的田间释放试验:首先应用性引诱剂降低田间野生雄虫数量;而后,释放橘小实蝇不育雄虫,进一步降低田间橘小实蝇种群数量;最后,释放阿里山潜蝇茧蜂对田间残余的橘小实蝇卵进行追踪寄生,以达到持续控制的目的。通过监测整个防控期田间橘小实蝇的种群数量以及果实受害率和防治效果作为评价指标评价该防治方法的综合防治效果。结果表明:应用阿里山潜蝇茧蜂、橘小实蝇不育雄虫并配合引诱剂的综合措施对橘小实蝇的种群数量有明显控制作用,田间总体防治效果可达90%左右。此外,提出完善橘小实蝇田间防控措施的建议,并提出该研究的不足以及有待进一步开展研究的方向。     

橘小实蝇、瓜实蝇和南亚果实蝇人工饲料的优化

在温度25²8℃、相对湿度70%28℃、相对湿度70%⁷5%和光照周期L∶D=14∶10条件下进行了人工大量饲养橘小实蝇Bactrocera dorsalis(Hendel)和瓜实蝇B.cucurbitae(Coquillett)成虫人工饲料配方的筛选试验。结果显示,1∶2重量比例混合的蔗糖和啤酒酵母是饲养这2种果实蝇的最佳成虫人工饲料,用其饲养的单雌产卵量、产卵期和孵化率分别为424.1675%和光照周期L∶D=14∶10条件下进行了人工大量饲养橘小实蝇Bactrocera dorsalis(Hendel)和瓜实蝇B.cucurbitae(Coquillett)成虫人工饲料配方的筛选试验。结果显示,1∶2重量比例混合的蔗糖和啤酒酵母是饲养这2种果实蝇的最佳成虫人工饲料,用其饲养的单雌产卵量、产卵期和孵化率分别为424.16⁴45.75粒,30.90445.75粒,30.90³1.87 d,74.60%31.87 d,74.60%⁷5.40%。同时,对18种由不同配方配制成的幼虫人工饲料饲养橘小实蝇、瓜实蝇和南亚果实蝇B.tau(Walker)的效果进行了比较。结果表明,玉米和麦麸作为饲料的介质优于麦片和麦麸。橘小实蝇幼虫人工饲料的优化配方为:玉米+麦麸(125 g+25 g),蔗糖25 g,啤酒酵母25 g,对羟基苯甲酸甲酯0.9 g,1 mol/L盐酸4 mL,纸巾4 g,自来水300 mL;用其幼虫人工饲料饲养该虫的生物学参数包括子代孵化率、化蛹率、羽化率和平均蛹重分别为81.17%±0.05%,96.41%±0.02%,94.85%±0.01%与(19.40±0.08)mg。而瓜实蝇和南亚果实蝇幼虫人工饲料的优化配方为:玉米+麦麸(100 g+50 g),蔗糖30 g,啤酒酵母25 g,以及一定量的其他组分(同上);用其饲料饲养这2种果实蝇的相关参数:子代孵化率、化蛹率、羽化率和平均蛹重分别为78.50%±0.04%与76.96%±0.12%,95.73%±0.03%与94.69%±0.02%,94.57%±0.02%与95.82%±0.03%,(18.62±0.23)mg与(22.83±1.38)mg。试验证实,优化后的成、幼虫人工饲料具有饲养效果好、方法简便,配方材料来源广泛和价格低廉等优点,可用于室内人工大量饲养上述3种果实蝇属害虫。     

瓜实蝇和南亚果实蝇在我国的分布差异

瓜实蝇Zelugodacus cucurbitae和南亚果实蝇Zelugodacus tau是两种主要以葫芦科植物为寄主的瓜类实蝇,主要分布于我国南部和中部地区。在实际研究中发现南亚果实蝇和瓜实蝇分类地位、寄主范围和生活史相近,但分布区域可能存在差异。因此,采用性诱剂诱集法在全国14个省(自治区)对这两种实蝇的分布进行调查,结果显示南亚果实蝇在我国整个南部地区均有分布,瓜实蝇在我国的分布范围较小,主要分布于北纬25°以南。结合气候数据发现两种实蝇的分布范围基本上和各地年平均气温一致,瓜实蝇主要在年平均温度20℃以上的区域分布,南亚果实蝇则在年平均温度为15℃以上的区域均有分布。这种地理分布的差异可能是两种实蝇对气候环境和寄主植物适应能力不同所致。     

二种大实蝇的PCR-RFLP快速鉴定方法

应用PCR-RFLP技术,对我国部分地区发生分布的蜜柑大实蝇和橘大实蝇开展了分子生物学鉴定方法研究。结果表明,利用4组引物对目标实蝇的COⅡ和ITS1基因进行PCR扩增,并借助MnlⅠ,MseⅠ,AseⅠ,DraⅠ和SspⅠ等5种限制性内切酶对扩增产物进行酶切,能从多个途径把2种大实蝇区分开。所建立的方法不受目标实蝇食物源、地理来源和标本保存条件的影响,对不同虫态和不同性别的个体均适用,可在生产和检疫实践中对蜜柑大实蝇和橘大实蝇进行快速鉴定。     

实蝇害虫抗药性研究进展

实蝇科昆虫中的橘小实蝇Bactrocera dorsalis、瓜实蝇B. cucurbitae、南亚实蝇B. tau、柑橘大实蝇B. minax和枣实蝇Carpomya vesuviana等害虫危害作物和果树后造成一定经济损失,而在生产中为追求快速高效常采用化学防治方法控制。但在长期化学防治过程中,实蝇害虫采取代谢、基因标靶、行为和肠道共生菌等系列机制对杀虫剂产生抗药性。本文综述实蝇害虫对杀虫剂的防治现状、抗药性、抗性机制及抗性治理策略,以期为其防治提供参考。     

云南西部实蝇的多样性

2005和2006年,在云南西部瑞丽、潞江坝、六库、保山、大理5个地区,采用信息素引诱法及被害瓜果内实蝇收集法对5个地区实蝇多样性进行分析.结果表明,5个地区实蝇丰富度的发生模式明显分为2种类型:瑞丽和潞江坝实蝇全年发生;六库、保山和大理实蝇季节性发生;瑞丽的实蝇种类丰富度最高,有20种,其次是潞江坝,11种,而保山、大理的实蝇种类丰富度低,分别为4种和3种;该区域实蝇优势种为桔小实蝇(Bactrocera dorsalis)和南亚果实蝇(B. tau);2年实蝇多样性指数均以六库最低,以潞江坝最高.各地实蝇种类相似性变化较大, 相似性系数在0.15～1.00 之间.结果为了解云南西部实蝇种类分布以及预防实蝇危害提供了基础数据.     

橘小实蝇寄生蜂切割潜蝇茧蜂的人工繁殖技术

切割潜蝇茧蜂[Psyttalia incisi(S ilvestri)]是福建疫区寄生于橘小实蝇[Bactrocera dorsalis(Hendel)]幼虫—蛹期的重要本地寄生蜂。利用室内大量繁殖的橘小实蝇幼虫作为寄主,在室内条件下对其进行人工繁殖技术研究,并设计了人工繁蜂的质量控制和工艺流程。旨在将来提供足够数量的寄生蜂来满足田间放蜂的需要,尽早实现对橘小实蝇的持续、有效地治理。     

Significance of flower and fruit thinning on fruit quality

The effects of mechanical or chemical flower and fruit thinning on fruitquality were primarily by altering crop load. However, there were alsodirect effects of thinning agents. Fruit size was directly related tothinning intensity. In addition to crop load, age of wood, flower budquality, competition within clusters and canopy were important factorsaffecting the response to thinning. Short- and long-term thinningstudies identified two groups of quality components: Group 1characteristics include size, colour, skin performance, firmness andsugar and acid content of the fruit. Group 2 characteristics wererepresented by inorganic components, especially calcium and potassiumwhich are implicated in the susceptibility of fruit to physiologicaldisorders. While group 1 characteristics were improved by increasingthinning intensity, storability of the fruit was better at high than atlow crop loads. Therefore, a compromise between all quality requirementsmust be found for a good economic return. Establishing the trends ofthinning on the different quality parameters can help to select athinning strategy for local or regional conditions typically beingdetermined by growing and market conditions.     

Effect of various phytoimmunocorrectors on fruit and soft fruit cultures

Catalase activity and induction of delayed chlorophyll fluorescence were shown to be the markers of plant native state. The dependence of reaction of the plant to exogenous elicitors, stimulators or inhibitors of defense system, on the age, cultivar and/or species was found. Prolonged effect of the treatment with phytoimmunocorrectors was observed. The necessity of careful choice of elicitors depending on the plant state was shown.     

Antisense inhibition of tomato fruit sucrose synthase decreases fruit setting and the sucrose unloading capacity of young fruit

The role of sucrose synthase (SuSy) in tomato fruit was studied in transgenic tomato (Lycopersicon esculentum) plants expressing an antisense fragment of fruit-specific SuSy RNA (TOMSSF) under the control of the cauliflower mosaic virus 35S promoter. Constitutive expression of the antisense RNA markedly inhibited SuSy activity in flowers and fruit pericarp tissues. However, inhibition was only slight in the endosperm and was undetectable in the embryo, shoot, petiole, and leaf tissues. The activity of sucrose phosphate synthase decreased in parallel with that of SuSy, but acid invertase activity did not increase in response to the reduced SuSy activity. The only effect on the carbohydrate content of young fruit was a slight reduction in starch accumulation. The in vitro sucrose import capacity of fruits was not reduced by SuSy inhibition at 23 days after anthesis, and the rate of starch synthesized from the imported sucrose was not lessened even when SuSy activity was decreased by 98%. However, the sucrose unloading capacity of 7-day-old fruit was substantially decreased in lines with low SuSy activity. In addition, the SuSy antisense fruit from the first week of flowering had a slower growth rate. A reduced fruit set, leading to markedly less fruit per plant at maturity, was observed for the plants with the least SuSy activity. These results suggest that SuSy participates in the control of sucrose import capacity of young tomato fruit, which is a determinant for fruit set and development.     

Banana harvest maturity and fruit position on the quality of ripe fruit

There is an increasing market demand for smaller banana fruit. The way that this is being addressed involves harvesting some fruits on a bunch at a less advanced stage of maturity. Experiments were carried out to investigate the effect of age of fruit at harvest, position of the fruit on the bunch and different banana varieties on the speed of ripening and the quality of the ripe fruit at two different ripening temperatures after being exposed to exogenous ethylene. The maturity of bananas at harvest affected both the speed of ripening and the quality of the ripe fruit. Speed of ripening of fruit at 13°C was slower the more immature the fruit at harvest, but there was no effect on the speed of ripening of harvest maturity at a ripening temperature of 16°C. The effects of harvest maturity and position of the fruit on the bunch on peel colour and texture were significant but so small that they would be unlikely to affect the consumers' perception in a commercial situation. The higher soluble solids, flavour, sweetness and acceptability after ripening of the more mature fruit at harvest was sufficiently high that consumers could probably detect them.     

Ethylene and fruit ripening

The latest advances in our understanding of the relationship between ethylene and fruit ripening are reviewed. Considerable progress has been made in the characterisation of genes encoding the key ethylene biosynthetic enzymes, ACC synthase (ACS) and ACC oxidase (ACO) and in the isolation of genes involved in the ethylene signal transduction pathway, particularly those encoding ethylene receptors ( ETR ). These have allowed the generation of transgenic fruit with reduced ethylene production and the identification of the Nr tomato ripening mutant as an ethylene receptor mutant. Through these tools, a clearer picture of the role of ethylene in fruit ripening is now emerging. In climacteric fruit, the transition to autocatalytic ethylene production appears to result from a series of events where developmentally regulated ACO and ACS gene expression initiates a rise in ethylene production, setting in motion the activation of autocatalytic ethylene production. Differential expression of ACS and ACO gene family members is probably involved in such a transition. Finally, we discuss evidence suggesting that the NR ethylene perception and transduction pathway is specific to a defined set of genes expressed in ripening climacteric fruit and that a distinct ETR pathway regulates other ethylene-regulated genes in both immature and ripening climacteric fruit as well as in non-climacteric fruit. The emerging picture is one where both ethylene-dependent and -independent pathways coexist in both climacteric and non-climacteric fruits. Further work is needed in order to dissect the molecular events involved in individual ripening processes and to understand the regulation of the expression of both ethylene-dependent and -independent genes.     

Impact of habitat structure and fruit abundance on avian seed dispersal and fruit predation

So far, it is poorly understood how differential responses of avian seed dispersers and fruit predators to changes in habitat structure and fruit abundance along land-use gradients may translate into consequences for the seed dispersal of associated plants. We selected a gradient of habitat modification (forest, semi-natural, and rural habitat) characterized by decreasing tree cover and a high variation in local fruit availability. Along this gradient we quantified fruit removal by avian seed dispersers and fruit predators from 18 Sorbus aucuparia trees. We analyzed the relative importance of tree cover and fruit abundance in explaining species richness, abundance and fruit removal rates of both guilds from S. aucuparia trees. Species richness and abundance of seed dispersers decreased with decreasing tree cover, whereas fruit removal by seed dispersers decreased with decreasing fruit abundance independent of tree cover. Both variables had no effect on species richness, abundance and fruit removal by fruit predators. Consequently, seed dispersers dominated relative fruit removal in fruit-rich sites but the dispersal/predation ratio shifted in favor of predation in fruit-poor habitat patches. Our study demonstrates that variation in local habitat structure and fruit abundance can cause guild-specific responses. Such responses may result in a shift in fruit removal regimes and might affect the dispersal ability of dependent fruiting plants. Future studies should aim at possible consequences for plant recruitment and guild-specific responses of frugivores to disturbance gradients on the level of entire plant–frugivore associations.     

Relationship between tomato fruit growth and fruit osmotic potential under salinity

To investigate the relationship between fruit growth and fruit osmotic potential (Ψ_s) in salty conditions, a sensitive tomato cultivar (Lycopersicon esculentum Mill.) and a tolerant accession of the wild species Lycopersicon pimpinellifolium Mill. were grown in a greenhouse with 0 and 70 mM NaCl, and the growth of the fruit studied from 15 to 70 days after anthesis (DAA). L. pimpinellifolium did not reduce significantly fruit weight in salty conditions throughout the growth period, whereas L. esculentum fruit weights decreased significantly with salinity from 45 DAA. L. esculentum fruit fresh weight reductions resulted from both less dry matter and water accumulation, although the fruit water content was affected by salinity before the fruit weight. In both species, fruit osmotic potential (Ψ_s) decreased significantly with salinity during the rapid fruit growth phase, although the changes were different. Thus, fruits from L. pimpinellifolium salt treated plants showed a Ψ_s reduction at the beginning (15 DAA) twice as high as that found in L. esculentum. As the advanced growth stage (from 15 to 55 DAA), the Ψ_s reduction percentages induced by salinity were quite similar in L. pimpinellifolium fruits, while increased in L. esculentum. Under saline conditions, the solutes contributing to reduce the fruit Ψ_s during the first 55 DAA were the inorganic solutes in both species, while in the ripe fruits they were hexoses. L. esculentum fruits accumulated K⁺ as the main osmoticum in salty conditions, while L. pimpinellifolium fruits were able to use not only K⁺ but also the Na⁺ provided by the salt.     

Associated evolution of fruit size,fruit colour and spines in Neotropical palms

Understanding how ecological interactions have shaped the evolutionary dynamics of species traits remains a challenge in evolutionary ecology. Combining trait evolution models and phylogenies, we analysed the evolution of characters associated with seed dispersal (fruit size and colour) and herbivory (spines) in Neotropical palms to infer the role of these opposing animal–plant interactions in driving evolutionary patterns. We found that the evolution of fruit colour and fruit size was associated in Neotropical palms, supporting the adaptive interpretation of seed‐dispersal syndromes and highlighting the role of frugivores in shaping plant evolution. Furthermore, we revealed a positive association between fruit size and the presence of spines on palm leaves, bracteas and stems. We hypothesize that interactions between palms and large‐bodied frugivores/herbivores may explain the evolutionary relationship between fruit size and spines. Large‐bodied frugivores, such as extinct megafauna, besides consuming the fruits and dispersing large seeds, may also have consumed the leaves or damaged the plants, thus simultaneously favouring the evolution of large fruits and defensive structures. Our findings show how current trait patterns can be understood as the result of the interplay between antagonistic and mutualistic interactions that have happened throughout the evolutionary history of a clade.     

Endogenous polyamines in apple and their relationship to fruit set and fruit growth

The distribution of free and bound polyamines was investigated from blooming until harvest on flower, fruitlets and fruits of Malus domestica Borkh cv. Golden Delicious, Relationships between polyamines and fruit set and growth were also investigated. The level of free polyamines was high only during the first weeks after full bloom and then decreased gradually. The amount of bound trichloroacetic acid-insoluble polyamines was much higher than free polyamines. Bound spermine in particular showed a high value for almost 40 days after full bloom, while spermidine and putrescine were no longer detectable even a few days after full bloom.
In relation to fruit set, it was possible to observe that abscission peaks took place when free polyamine levels were low or decreasing. Insofar as fruit growth is concerned, the most substantial variations in polyamine levels occurred very early in the season when fruit dry weight and protein amount were also changing rapidly and fruit diameter was almost impossible to measure.