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Secretions from the metathoracic glands (MTG) of the black locust bug, Lopidea robiniae (Uhler) (Heteroptera: Miridae) contained six major compounds, including (E)-2-hexenal, (E)-2-hexen-1-ol, (E)-2-octenal, (E)-2-octen-1-ol (E)-2-heptenal, and (Z)-3-octen-1-ol. Males and females did not differ significantly in the relative compositions of identified compounds. In feeding trials, six bird species [robin (Turdus migratorious), blue jay (Cyanocitta cristata), brown thrasher (Toxostoma rufum), killdeer (Charadrius vociferus), starling (Sturnus vulgaris), and house wren (Troglodytes aedon)] demonstrated feeding aversions towards L. robiniae, implying that black locust bugs are chemically defended. Bugs discharged the liquid contents of their MTG when attacked, thereby producing a strong and distinct odor. Some birds immediately ejected bugs out of their mouth after biting them, suggesting that the MTG secretion was a deterrent. 相似文献
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应用正交设计法研究6-BA,NAA及琼脂等3个因子对四倍体刺槐组培苗生根率的影响,试验按正交表L16(45)形成3因素、4水平的不同配比。试验结果表明:最佳的增殖培养基是1/2MS+6-BA0.5mg/L+NAA0.1mg/L+琼脂6g/L。 相似文献
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Tree mortality and regeneration in riparian areas are greatly influenced by flooding. The elevational distribution of Salix spp. and Robinia pseudoacacia were investigated by observing densities and standing conditions before and after a major flood on a sediment bar in the middle reaches of the Arakawa River in Kumagaya, Japan. The subsequent tree recruitment was also examined. R. pseudoacacia was easily washed away with the eroded sediment, whereas Salix spp. was found to be more tolerant. Both species were able to survive even after collapsing, provided that their roots were fully or partially embedded in the sediment. Re‐shooting of collapsed trees, rather than emergence from saplings (either by seeds or vegetative fragments), was observed to be the major method of recruitment after the flood. Therefore, tree density before the flood was unchanged, unless the trees were subject to washing away. Salix spp. recruitment was mainly observed in low‐lying areas and R. pseudoacacia in elevated areas. Recruitment from saplings was species‐specific. Salix spp. at high elevations originated mainly from shoot fragments as they need high levels of moisture for seed germination and at higher elevations, sediment moisture content is very low. R. pseudoacacia, on other hand, originated mainly from roots and seeds. At a given elevation, past recruitment patterns indicated that the annual recruitment of trees increased with tree density up to a particular threshold of recruitment density. Further increases in tree density beyond that optimum value resulted in a decline in recruitment. Furthermore, threshold density was observed to increase along with elevation for R. pseudoacacia while declining with Salix spp. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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通过室内盆栽和大棚药效试验,研究了刺槐叶片提取物对黄瓜白粉病的防治效果.室内盆栽试验表明,在刺槐提取物浓度为40 mg/mL时,对黄瓜白粉病的防治效果可以达到90.31%,刺槐提取物的EC5o为3.49 mg/mL.随着提取物浓度的增大,发病情况逐渐减轻.大棚药效试验表明,刺槐提取物的浓度为20 mg/mL时,其81.97%的防效高于三唑酮73.61%的效果,每隔7d喷施一次刺槐提取物,能够有效预防黄瓜产果期发生白粉病. 相似文献
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利用Landsat ETM+数据检测人工刺槐林冠健康 总被引:1,自引:0,他引:1
通过发展一种基于单景Landsat TM/ETM+数据客观、可靠、简单易行的人工刺槐林冠健康检测方法,为人工刺槐林地健康监测和管理服务。以孤岛林场的一块近乎纯人工刺槐林地为试验区,首先选择当地刺槐完全展叶时的2000年5月2日的Landsat ETM+数据进行几何精校正,并将第6波段重采样为与第1~5和7波段相同的空间分辨率30 m,然后将波段1~5和7波段数据校正到大气顶层反射率以减少传感器和数据获取方面的影响,利用第6波段计算亮度温度。接着进行3种组合的ISODATA非监督分类(健康或轻度枯梢、中度枯梢、重度枯梢或死亡或灌丛、非植被):波段1~5和7,归一化后的缨帽变换Tasseled Cap Transform(TCT)绿度和湿度成分,归一化后的缨帽变换Tasseled Cap Transform(TCT)绿度、湿度成分和亮度温度。结果发现,增加了第6波段信息(亮度温度)的第3种组合对人工刺槐林冠健康检测更有效。 相似文献
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Robinia pseudo-acacia L. (black locust) is a nonindigenous species currently invading the central part of Japanese grasslands. Several allelochemicals were identified and characterized from the leaf tissue. The growth of both radicle and hypocotyl in the tested species (barnyard grass, white clover, lettuce, and Chinese cabbage) was reduced when grown in soil mixed with the leaves of R. pseudo-acacia at various concentrations. Aqueous leaf extracts, when bioassayed, exhibited a significant suppression of radicle growth. Chromatographic separation of an ethanolic extract of R. pseudo-acacia leaves resulted in isolation of three compounds, identified as robinetin (1), myricetin (2), and quercetin (3) by nuclear magnetic resonance and mass spectroscopy. All inhibited root and shoot growth of lettuce. Robinetin, found in a large amount, caused 50% suppression of the root and shoot growth of lettuce at 100 ppm. The presence of these bioactive substances in leaf tissue suggests a potential role for flavonoids in R. pseudo-acacia invasion in introduced habitats. 相似文献