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1.
[目的]探讨颜色和气味对红锯蛱蝶觅食的引诱作用。[方法]分别测定不同颜色和挥发性信息化合物对红锯蛱蝶的引诱效应。[结果]实验发现:视觉和嗅觉信号对红锯蛱蝶觅食均有引诱作用,红、粉、黄、紫、白5种颜色中,红锯蛱蝶明显偏好白色假花(占总访问次数的56.67%),对黄色(20.00%)和粉红色(15.00%)假花的趋性次之;灯光的选择中,夜晚的引诱效果好于白天,粉红色灯光(42.22%)对红锯蛱蝶的诱集效果最好;红锯蛱蝶对蜜源信息挥发物有明显的趋性,无气味时,访花次数较少,添加气味后,访花次数急剧增加,其中,1%水杨酸甲酯(35.17%)和化合物组合(1%α-蒎烯+1%水杨酸甲酯+1%1-辛醛)(32.42%)对红锯蛱蝶的引诱效果最明显。[结论]研究表明:视觉和嗅觉信号均在红锯蛱蝶的觅食过程中发挥作用,但觅食时更侧重依赖嗅觉信号选择合适的食物。红锯蛱蝶明显偏好白色,可能与白色的强反光能力有关。 相似文献
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[目的]为摸清金斑蝶成虫的行为特征,[方法]在田间的网室内跟踪观察其飞行、取食、求偶、交配和产卵行为。[结果]表明:金斑蝶成虫羽化主要集中在8:00—10:00,成虫羽化当天基本处于停歇状态;羽化第2天起至交配前,雌雄成虫的日平均飞行次数及日平均飞行时间均逐渐增加,雄成虫的日飞行高峰在13:00—15:00,雌成虫的日飞行高峰期在9:00—11:00和15:00—17:00,雌雄成虫的日平均飞行次数、平均飞行时间和日飞行规律的差异均不显著(p0.05);飞行次数与飞行时间均呈显著正相关(雌蝶:r=0.978,p0.05;雄蝶:r=0.957,p0.05)。金斑蝶雌雄成虫羽化次日开始取食,自羽化第2天起,雌雄成虫的日平均取食次数及日平均取食时间均逐渐增加,雄虫的日取食活动高峰期在9:00—11:00,雌虫日访花高峰期在11:00—13:00和15:00—17:00,雌雄成虫的日平均取食次数、平均取食时间和日取食规律的差异均不显著(p0.05);取食次数与取食时间均呈不显著正相关(雌蝶:r=0.949,p0.05;雄蝶:r=0.853,p0.05)。最早交配时间发生在羽化第4天,雌雄成虫均可多次交配,交配主要发生在14:00—16:00。产卵时间主要在11:00—13:00,雌成虫的产卵方式为散产,主要产卵于寄主植物叶片背面。[结论]金斑蝶成虫期可分为运动器官成熟阶段、补充营养和促进生殖器官发育阶段、求偶和交配阶段、产卵等4个阶段,各阶段内行为有交叉。 相似文献
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应用扫描电镜对枯叶蛱蝶成虫触角及其感器外部形态进行观察和研究,结果表明:枯叶蛱蝶触角为棒状,其上共有5类感器,即B(o)hm氏鬃毛、鳞形感器、毛形感器(Ⅰ、Ⅱ)、腔锥形感器和刺形感器,并对各类型感器的分布和数量进行了描述.雌雄虫触角感器形态相同,在感器数量与分布上,只在鳞形感器、毛形感器(Ⅱ)的数量以及腔锥形感器分布上略有差异,其他感器类型的数量和分布都没有明显差异.在感器总数上,雄虫多于雌虫,但雌雄触角性二型现象依然不明显.对其触角的研究是探索其嗅觉识别机制的前提. 相似文献
5.
松褐天牛交尾产卵行为和卵期、孵化率测定 总被引：5，自引：0，他引：5
松褐天牛 Monochamus alternatus Hope成虫交尾 ,雌雄均无专一性 ,既能一雄多雌 ,也能一雌多雄 ;交尾次数对产卵量和卵的孵化率无显著影响 ;成虫对产卵场所的树种和树性有显著的偏嗜性选择行为。据测定 ,在 6月下旬至 7月下旬平均卵期 4.0 4天 ,卵的孵化率为 85 .76%。 相似文献
6.
通过EAD和“Y”型嗅觉仪测定光肩星天牛对5种槭树的40种挥发物及挥发物混合物的嗅觉电生理及嗅觉行为反应进行研究的结果表明：糖槭挥发物的主要成分为酯类、烯类、酸类和醇类,复叶槭为酯类、醛类和烷烃类,五角槭为酯类和醛类,华北五角槭为酯类、烯类和醇类,而挪威槭为酯类、醛类和醇类。光肩星天牛雌成虫对5种槭树的21种挥发物存在明显的的EAD反应,而雄成虫则对12种挥发物存在明显的EAD反应;其中雌雄成虫对11种挥发物均存明显的EAD反应。进一步嗅觉行为测定发现,光肩星天牛雌成虫对11种挥发物存在正趋向反应,雄成虫对7种挥发物存在显著的正趋向反应,具有明显的引诱作用,其中7种挥发物对雌雄均表现出引诱作用。雌成虫对8种挥发物存在负趋向反应,雄成虫对10种挥发物存在显著的负趋向反应,具明显的驱避作用,其中4种挥发物对雌雄成虫均表现出驱避作用。光肩星天牛雌雄成虫对5种槭树挥发物混合物的嗅觉反应都表现为正趋向反应,引诱率大小依次为糖槭、复叶槭、五角槭、挪威槭和华北五角槭。 相似文献
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[目的]通过对松材线虫的媒介松墨天牛的防控以达到控制松材线虫病的目的。[方法]通过查阅国内外相关文献,对松墨天牛成虫行为与化学生态学进行归纳总结。[结果]松墨天牛成虫活动范围较小,当食物短缺时会远距离迁飞。大部分成虫补充营养10 d后才开始交配,交配分为三个阶段:雌雄成虫共同受寄主植物挥发物吸引,雄虫通过短距离信息素吸引雌虫,再通过接触信息素识别雌虫。植物挥发物如α-蒎烯和乙醇等可以引起松墨天牛成虫的反应,樟子松墨天牛雄虫分泌的聚集信息素2-undecyloxy-1-ethanol能同时引诱雄虫和雌虫,使用植物挥发物与聚集信息素复配研制出的引诱剂如APF-I型引诱剂引诱松墨天牛时,效果比单独使用更加显著,是一种灵敏高效、环境友好、不易产生抗性的防治方法。视觉在松墨天牛活动中具备一定的指导作用,使其对褐色有较大的选择偏向性,当复眼被涂黑后交配成功率也相对下降。进行取食选择时,选择健康木优先于衰弱木,进行产卵选择时则相反。未交配松墨天牛对健康松枝挥发物的触角电位反应值比被害松枝挥发物的反应值大,交配后的松墨天牛触角电位反应与交配前相反。产卵后雌虫会在产卵孔分泌包含产卵忌避信息素的胶状物,防止其他雌虫在此处产卵。[结论]可以使用引诱剂防治松墨天牛,也可以应用天敌生物花绒寄甲、白僵菌和管氏肿腿蜂等防控松墨天牛。 相似文献
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【目的】以雌雄异株山鸡椒为研究材料,分析雌雄植株在生殖生长过程中水分及氮素利用策略的性别特异性动态变化规律,以期为雌雄异株植物资源分配动态变化机制提供理论依据。【方法】测定雌雄植株在开花后105～165天共5个时期叶片养分含量(碳含量、氮含量、碳氮比)、稳定碳同位素组成(δ13C)、稳定氮同位素组成(δ15N),并分析其动态变化规律。【结果】1)雌雄株叶片δ13C平均值分别为-29. 38‰和-28. 08‰。性别和发育时期对雌雄株叶片δ13C值影响均显著,5个时期雌株δ13C值均显著低于雄株;且随发育进程雌雄植株δ13C值均不断下降。2)雌雄株叶片δ15N平均值分别为1. 90‰和2. 95‰。性别和发育时期对雌雄株叶片δ15N值均有极显著影响,开花后105～150天(即雌株果实中精油及柠檬醛含量快速积累期)雌株δ15N值显著低于雄株;随着发育进程,雌雄株叶片δ15N值均表现出双峰变化趋势,双峰出现在开花后105天和135天,雌株叶片δ15N在开花后120天达到最低值,雄株叶片在开花后165天时达到最低值。3)雌雄株叶片碳含量平均值分别为49. 44%和49. 28%。开花后105天和120天,雌株叶片C含量高于雄株叶片C含量,开花后135～165天(果实精油快速积累期到稳定期),雌株叶片C含量低于雄株。雄株叶片C含量随发育进程显著升高,而雌株叶片C含量在不同时期无显著差异。4)雌雄株叶片N含量平均值分别为1. 71%和1. 51%。性别对N含量影响显著,雄株叶片N含量均低于雌株(除开花后135天)。5)雌雄株叶片C/N平均值分别为29. 15和33. 72。性别对叶片碳氮比影响显著,雌株C/N值在不同发育时期均小于雄株,但发育时期对其无显著影响;随着发育时期推进,雄株C/N值下降程度高于雌株。6)雌雄植株叶片δ13C与N含量以及δ13C与δ15N之间均无显著相关性。【结论】山鸡椒雌雄植株在养分含量、水分及氮素利用策略存在差异,且在开花后105～165天表现出动态变化规律。雌株水分利用效率低于雄株,从果实精油及柠檬醛含量快速积累期到稳定期,雌株水分利用效率不断下降;雌株氮利用低于雄株,且随着植株发育,雌雄株叶片氮素利用效率均表现出双峰变化趋势;雄株叶片氮含量低于雌株,分配更多的氮素至花芽以保证花粉形成;果实精油快速积累期到稳定期,雌株叶片碳含量低于雄株,为果实及种子的形成提供更多的碳元素。 相似文献
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[目的]在用材林高世代种子园建园材料选择时,最初重点考虑的是其速生性,而对优树的开花物候关注较少。在高世代种子园营建时,无性系的配置常根据其种源在大范围内考虑其开花物候的遗传因素,但即使是小范围内相同种源的无性系,其开花物候也不可能绝对同步。因此,了解种子园无性系的开花物候,可为种子园的集约经营、产量预测、种子遗传品质调控等提供依据。[方法]于2012—2013年,在桂阳县苗圃马尾松二代种子园Ⅰ大区、Ⅴ大区分别随机选取不同类型的无性系10个和25个,对其开花物候进行观测。[结果]表明:不同无性系的雌、雄球花花期起止日期和持续时间均有差异,但无性系间雌、雄球花花期值差异均未达显著水平,35个无性系总体雌、雄球花花期具有一定的同步性;35个无性系雌、雄球花的初花期基本同步,雌、雄球花的盛花期和末花期同步。株间花期差异相对于无性间要大,但雄球花花期较早的植株,其雌球花花期也较早,同一株建园亲本的雌、雄球花花期有一定的同步性。除雌球花的末花期与雄球花的初花期呈微弱负相关外,雌、雄球花的初花期、盛花期、末花期间均呈极显著或显著正相关。各花期的相关性呈现初花期和盛花期的相关盛花期和末花期的相关初花期和末花期的相关,雌球花初花期与雄球花初花期的相关系数最大。坡位对母树的花期有极显著影响,生长在不同坡位的植株,其雌、雄球花花期值差异明显,其大小均为上坡中坡下坡。坡位对花期影响最大的是雌球花的初花期,其次是雄球花的初花期、雌球花的盛花期、雄球花的盛花期,而对雌、雄球花的末花期影响最小。偏北产地无性系的花期相对较早,不同的无性系类型,其雄球花的盛花期和雌球花的初花期的差异显著;雄球花的初花期、末花期以及雌球花的盛花期和末花期差异均不显著。不同的年份,雌、雄球花花期的早晚差异很大,2012年最早初花期较2013年最早初花期早25 d。[结论]桂阳马尾松二代种子园35个无性系总体雌、雄球花花期具有较好的同步性;从开花物候方面考虑,该种子园建园材料选择较合理,对种子园种子产量和遗传品质没有影响。 相似文献
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[目的]探究对枣实蝇有引诱作用的挥发性物质,研发基于行为调节的防治技术。[方法]采用Y型嗅觉仪测定了枣实蝇成虫对6种枣果挥发物的选择行为反应,并在室内试验的基础上进行田间引诱试验。[结果]室内试验结果显示,枣实蝇成虫对6种枣果挥发物具有显著正趋性。枣实蝇雌虫对棕榈酸乙酯、月桂酸乙酯、肉豆蔻酸的选择率较强,选择率均为30%以上;雄虫对亚油酸乙酯、油酸乙酯的选择率较强,选择率均为25%以上,从不同浓度梯度(原液、10%溶液、1%溶液)的选择率和选择系数来看,随浓度的递减,其选择率和选择系数也在递减,原液的选择率分别为10%溶液及1%溶液的2.5倍及5倍以上。田间试验发现:肉豆蔻酸对枣实蝇雌虫的诱集效果较强,2 d最多诱捕数量为15头·只^-1,平均诱捕数量为11.4头·只^-1,十四酸乙酯次之。在6种不同挥发物中油酸乙酯和亚油酸乙酯对枣实蝇雄虫的引诱效果较强。经单因素方差分析发现,在6种挥发性物质及混合物中,月桂酸乙酯及十四酸乙酯对枣实蝇雌雄虫的引诱效果之间存在显著性差异。其他挥发物之间无显著差异。[结论]枣果挥发物中棕榈酸乙酯、月桂酸乙酯、肉豆蔻酸与枣实蝇偏爱选择密切相关。在田间试验中:枣实蝇成虫对肉豆蔻酸的选择率较强,为研发枣实蝇引诱剂提供了理论依据。 相似文献
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Effects of soil water availability on seedling growth, dry matter production and allocation were determined for Gympie (humid coastal) and Hungry Hills (dry inland) provenances of Eucalyptus cloeziana F. Muell. and for E. argophloia Blakely (dry inland) species. Seven-month-old seedlings were subjected to well-watered (100% field capacity, FC), moderate (70% FC) and severe (50% FC) soil water regimes in a glasshouse environment for 14 wk. There were significant differences in seedling growth, biomass production and allocation patterns between species. E. argophloia produced twice as much biomass at 100% FC, and more than three times as much at 70% and 50% FC than did either E. cloeziana provenance. Although the humid provenance of E. cloeziana had a greater leaf area at 100% FC conditions than did the dry provenance, total biomass production did not differ significantly. Both E. cloeziana provenances were highly sensitive to water deficits. E. argophloia allocated 10% more biomass to roots than did E. cloeziana. Allometric analyses indicated that relative biomass allocation patterns were significantly affected by genotype but not by soil water availability. These results have implications for taxon selection for cultivation in humid and subhumid regions. 相似文献
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Contour hedgerows of multipurpose tree species in the sloping tea lands of Sri Lanka are expected to reduce soil erosion and
also add significant amounts of plant nutrients to the soil via periodic prunings. The objective of this experiment was to characterize the biomass decomposition pattern and quantify the
amount of nutrients added through prunings of six tree species (Calliandra calothyrsus, Senna spectabilis, Euphatorium innulifolium, Flemingia congesta, Gliricidia sepium and Tithonia diversifolia) currently being used in hedgerows associated with tea. Withered leaf and stem prunings (50 g) were enclosed in 2-mm litter
bags, placed at 5-cm depth and retrieved after one, three, six, nine and 12 weeks. Loss of initial dry weight, N, P and K
was measured. Single exponential decay function adequately described both dry weight and nutrient loss. Tree species differed
significantly in their rate of breakdown with decomposition constants (k) varying from 0.0299 to 0.2006 week−1 for leaves and from 0.0225 to 0.0633 week−1 for stems. Gliricidia showed the highest k for leaves with the rest in the following descending order: Senna > Tithonia ≥ Euphatorium > Calliandra > Flemingia. A similar pattern was observed for loss of all nutrients with Calliandra and Flemingia always having lower k values than the rest. Although N immobilization was not observed, immobilization of P and K was observed
during the first week of incubation in some species, particularly in stem prunings. Annual biomass of prunings differed significantly
between tree species in the following descending order: Calliandra > Senna > Flemingia > Tithonia > Gliricidia > Euphatorium. Calliandra added the greatest amount of nutrients annually to the soil with Euphatorium adding the least. Calliandra prunings provided the annual total K requirement and 49% of the N requirement of mature tea. However, none of the species
provided more than 5% of the P requirement. It is concluded that among the tree species tested, Calliandra and Flemingia are the most suitable for contour hedgerows in tea plantations of this agroclimatic region because of their higher soil nutrient
enrichment capacity and slower decomposition rates which would minimize leaching losses.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
13.
Trees and shrubs as sources of fodder in Australia 总被引：2，自引：0，他引：2
E. C. Lefroy P. R. Dann J. H. Wildin R. N. Wesley-Smith A. A. McGowan 《Agroforestry Systems》1992,20(1-2):117-139
Experience with browse plants in Australia is briefly reviewed in terms of their forage value to animals, their economic value to the landholder and their ecological contribution to landscape stability. Of the cultivated species only two have achieved any degree of commercial acceptance (Leucaena leucocephala and Chamaecytisus palmensis). Both of these are of sufficiently high forage value to be used as the sole source of feed during seasonal periods of nutritional shortage. Both are also leguminous shrubs that establish readily from seed. It is suggested that a limitation in their present use is the reliance on stands of single species which leaves these grazing systems vulnerable to disease and insects. Grazing systems so far developed for high production and persistence of cultivated species involve short periods of intense grazing followed by long periods of recovery. Similar management may be necessary in the arid and semi-arid rangelands where palatable browse species are in decline. 相似文献
14.
Comparative water use by dryland trees in Parklands in Senegal 总被引：1，自引：1，他引：1
Despite the clear evidence of competition for water between trees and crops, there have been very few studies comparing simultaneous water use by differing tree species in drylands. Comparative water use by dryland trees was measured in Senegal using heat balance gauges at the end of the wet season and in the dry season. Significant differences between tree species were found for maximum rates of water use per unit leaf area. Indigenous species may be better adapted to the dry environment than exotic species but the indigenous species Acacia seyal Del. used more water per unit leaf area than all other species. The exotic species Azadirachta indica Adr. Juss. consistently used less water per unit leaf area than most other species. There were significant differences in amounts of water used per unit leaf area by differing provenances of the same tree species. Water use in the dry season varied by a factor of three between two provenances of Acacia aneura F. Muell ex Benth. indicating potential to select provenances for drylands based on their water use characteristics. Absolute rates of water use as well as differences in sapflow between species were greatest when soils were moist suggesting that comparative sapflow studies will be most informative when carried out during the wet season. Water use rankings of the differing tree species were broadly maintained irrespective of season.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
15.
Agroforestry tree selection in central Chile: biological nitrogen fixation and early plant growth in six dryland species 总被引：5，自引：0，他引：5
Growth rate, resource partitioning, and several biological traits related to biological N2 fixation for six native or non-native tree species were compared using 15N isotope dilution techniques. The trees were field grown for six years in a semiarid mediterranean-climate region with five to six months a year of absolute drought. Trees were tested as candidates for new agroforestry systems being developed in central Chile to improve soil fertility and land health, while also increasing productivity and profitability for landowners and animal breeders. Four nitrogen-fixing legume trees (NFTs) were tested: Acacia caven (Mol.) Mol.Prosopis alba Griseb., P. chilensis (Mol.) Steuntz. emend. Burk., and Tagasaste ( Chamaecytisus proliferus L.f. subsp. palmensis (Christ.)Kunkel). Additional, non-nitrogen-fixing trees were the slow-growing native Huingán (Schinus polygamus (Cav.) Caberera and the fast-growing European Ash (Fraxinus excelsior L.). Among the NFTs, highly contrasting patterns in biological nitrogen fixation (BNF) were detected, for Ndfa (proportion of N derived from atmosphere), nodule efficiency (NE = gN fixed g–1 nodules), and N content in leaves, stems and roots. Tagasaste produced 2.5–25 times more biomass and fixed 4.5 to 30 times more atmospheric nitrogen than the South American Acacia and Prosopis species. Ndfa reached 250 g plant–1 in Tagastaste, in the sixth year, with NE = maximum 2.68 in the 4th year, and 1.12 in the 6th year. In contrast, Acacia caven had by far the highest NE of the four NFTs – 12.13 in the 4th year and 6.6 in the 6th year. Whereas BNF in Tagasaste peaked in the fourth year, and declined thereafter, BNF in Acacia caven increased steadily over six years. Fraxinus excelsiorand Schinus polygamus had growth rates and biomass accumulation intermediate between that of Tagasaste and the South American NFTs.Results are discussed in relation to agroforestry, restoration of soil fertility, and ecological and economic rehabilitation of damaged ecosystems and landscapes.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
16.
The aim of this study was to evaluate the effects of tree coppicing on tree-crop competition in farmed parkland and in alley farming, both in semiarid Burkina Faso.Azadirachta indica A. Juss (neem) was studied in the parklands, while neem,Albizia lebbeck (L.) Benth. (albizia) andLeucaena leucocephala (Lam.) de Wit (leucaena) were investigated in the alley farming system. The crop was sorghum (Sorghum bicolor (L.) Moench) in both cases.Under non-coppiced neem trees in the parkland, the sorghum yield at 0–3 m distance from the tree (under the tree canopy) was 82% of open field yields at 6–9 m distance, but the difference was not significant (p=0.07). Close to trees (0–3 m distance) which had been coppiced before planting, the sorghum yield was 148% of open field yields. In alley farming, early coppicing was superior; sorghum yields were highest close to trees coppiced early and lowest close to trees coppiced late.
Résumé La présente étude se propose d'évaluer les effets de la taille sur la concurrence entre arbres et cultures dans les parcs arborés et dans les cultures en couloir, en climat semiaride (Burkina Faso). Les espèces étudiées ont été:Azadirachta indica A. Juss (neem) dans les parcs et neem,Albizia lebbeck (L.) Benth. (albizia) ainsi queLeucaena leucocephala (Lam.) de Wit (leucaena) dans les cultures en couloir. Dans les deux cas la plante cultivée concerné a été le sorgho blanc (Sorghum bicolor (L.) Moench).Sous les neems non taillés des parcs, le rendement du sorgho cultivé de 0 à 3 m de l'arbre (sous le bouppier de l'arbre) a atteint 82% du rendement obtenu en plein champ, soit à une distance de 6 à 9 m de l'arbre (différence non significative,p=0.07). Une taille effectuée en début de campagne a entraîné un accroissement du rendement de 148% pour les cultures situées de 0 à 3 m de l'arbre, par rapport aux rendements en plein champ.Dans les cultures en couloir, on a constaté qu'une taille precoce est préférable, c'est à dire que les rendements de sorgho ont été supérieurs dans les lignes proches des arbres taillés tôt que dans celles proches des arbres taillés tard.相似文献
17.
The aim of this study was to quantify the effects of different soil scarification methods on tree growth. Soil scarification influenced stem volume and stem biomass yield of lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) in a 17-year-old field trial in boreal Sweden. Soil scarification (disc trenching, mounding and ploughing) resulted in an average stem volume yield of 3.1 and 34.2 m3 ha–1 on the poor and intermediate sites, respectively, while corresponding values for no soil scarification were 0.9 and 16.7 m3 ha–1. In comparison to no scarification, ploughing increased volume yields by 500% on the poor site and by 200% on the intermediate sites. The ranking according to stem volume yield was ploughing > disc trenching = mounding no soil scarification. Averaged over the two sites, the mean annual increment of stem biomass was 219% and 145% higher (in d.w., 0.26 kg and 0.34 kg per sample tree) after ploughing compared with no soil scarification, for the average and dominant sample trees, respectively. Although not significant, the increased growth rate after soil scarification decreased the average stem basic wood density of the sample trees with 1.6% and 5.3%, at the poor and intermediate sites, respectively. In conclusion, soil scarification significantly increased the 17-year stem volume yield compared with no scarification. The results also indicate that the difference in stem biomass yield between ploughing and the other methods, especially no soil scarification, will increase even more in the near future. 相似文献
18.
Nicolas Desneux Jean-Michel Rabasse Yannick Ballanger Laure Kaiser 《Journal of pest science》2006,79(2):95-102
In light of a recent increase in the aphid populations on young canola (Brassica napus) in autumn in Northwestern Europe, we carried out a survey of their parasitoid species during this season. The study was
done in France from 1998 to 2001 using different sampling methods. Results highlighted the presence of two main species of
Aphidiinae, Aphidius matricariae and Diaeretiella rapae (and to a lesser extent Aphidius ervi) on Myzus persicae, and of D. rapae on Brevicoryne brassicae. Nine other Aphidiinae species were found occasionally as well as some Aphelinidae parasitoids and hyperparasitoids. There
was no difference in parasitoid species pattern between fields in Northern and Southern France. The principal parasitoid species
found in the fields were reared in the laboratory to confirm their ability to develop on the canola aphids. Aphidius matricariae and D. rapae were reared successfully on M. persicae, but a low parasitism rate was obtained for A. ervi on this aphid. This study showed that A. matricariae and D. rapae could develop on aphids on canola and that they are present naturally in canola in autumn. However, the parasitism rate is
low in autumn, so the options could be the use of these parasitoids in augmentative release biological control programs or
in an IPM project on canola fields during this time of the year. 相似文献
19.
Lirussi D Li J Prieto JM Gennari M Buschiazzo H Ríos JL Zaidenberg A 《Fitoterapia》2004,75(7-8):718-723
In this work, we assessed the effect of extracts obtained from 17 plants used in traditional Chinese medicine. These extracts were tested in vitro with the epimastigote form of Trypanosoma cruzi, clone Bra C(15) C(2), at 27 degrees C in F-29 medium at a concentration of 100 microg/ml in axenic cultures. Allopurinol was used as reference drug. Seven plant extracts showed inhibitory activities lower than 25%. Pueraria lobata, Mahonia beaei, Dictamus dasycarpus, Kochia scoparia, Sophora flavescens and Ligustrum lucidum showed effects with inhibition values between 25% and 60%, whereas Lithospermum erythrorhizon, Saussurea lappa, Melia toosendan and Cinnamomum cassia showed the greatest inhibitory activity of 100%. The IC(50) of these extracts were: 0.4, 2.4, 1.8 and 3.9 microg/ml, respectively. The MTT assay was made and did not show cytotoxic activity. These results allowed us to suggest that L. erythrorhizon, S. lappa, M. toosendan and C. cassia could be a source of new compounds against T. cruzi. 相似文献
20.
In this study we determined soil moisture storage, evapotranspiration (ET) and light interception in an agroforestry trial consisting of pine trees grown over (1) control (bare ground), (2) ryegrass/clovers (Lolium perene/Trifolium spp.), (3) lucerne (Medicago sativa), and (4) ryegrass only during the third growing season between 1992 and 1993. The results show that:
相似文献
| 1. | In the period when rainfall was frequent and exceeded the evaporative demand (Epot), ET and depletion of soil moisture were not affected by the ground cover treatments. During summer when rainfall was less frequent, but with moisture readily available in the soil profile, ET was associated with plant canopy, and was significantly higher for the pasture ground covers than for the control. Therefore, the more rapid growth by lucerne caused higher ET in this ground cover than in the ryegrass/clovers ground cover in which the pasture was slow growing. At the end of the study period, total ET was in the following order: lucerne (757 mm) > ryegrass/clovers (729 mm) > Control (618 mm). |
| 2. | ET was dominated by pasture transpiration (Ep) during most of the growing season, but by tree transpiration (Et) in winter when large parts of the pasture canopy was shaded. Ep was always at least 16% higher for lucerne than for ryegrass/clovers species as a result of a greater radiation intercepted by the former. |
| 3. | Fraction of incoming radiation intercepted by the tree crowns was in the following order: control > ryegrass > ryegrass/clovers > lucerne. At the end of the one-year period, fraction of intercepted radiation was 140% greater for control than for lucerne ground cover. |
| 4. | The control produced the largest tree crowns, which were almost twice the tree crowns in the lucerne ground cover which produced the smallest trees. Accordingly, the trees in the control intercepted more radiation and rainfall, with the former being lost to evaporation, than the trees in the pasture. |
| 5. | The fractions of radiation intercepted and ET accounted for by the trees and pastures were associated with the proportion of the plot area they occupied. |