Effects of non-repellent termiticides on the tunneling and walking ability of the eastern subterranean termite (Isoptera: Rhinotermitidae)

BACKGROUND: Non-repellent insecticides, including fipronil and indoxacarb, are becoming increasingly important for soil treatments to manage the eastern subterranean termite, Reticulitermes flavipes (Kollar). The effects of these insecticides on termite walking and tunneling behavior could significantly reduce their efficacy against colonies. RESULTS: Groups of R. flavipes were exposed to several concentrations of commercial formulations of fipronil and indoxacarb, and the ability of treated termites to tunnel in soil and walk was assessed. Increasing insecticide concentration resulted in a reduction in the ability of R. flavipes to walk, tunnel and form tunnel branches; the importance of these effects on the use of non-repellent insecticides is discussed. CONCLUSION: Exposure of R. flavipes to 1, 10 or 50 mg L⁻¹ of fipronil or 50, 100 or 200 mg L⁻¹ of indoxacarb significantly reduced termite walking and tunneling and the number of tunnel branches. Distance walked (ca 73 mm) by untreated control termites did not change over time for at least 16 h after treatment; control termites formed ca 150 cm of tunnels with ca 40 branches. Copyright © 2012 Society of Chemical Industry     

高寒牧区当年生人工混播草地建植试验

通过试验证明，在碌曲县高寒草甸草地区建立一年生人工草地，采取禾本科与豆科牧草混播，可明显提高草地产革量和牧草品质。由于草层结构合理，促进了产草量的提高，混播草地产草量较单播平均提高26％，差异极显著(P＜0．01)；混播处理茎叶比明显低于单播，其中燕麦抽穗期降低0．56，完熟期降低2．55，说明随着牧草生长期的延长，混播草地叶量明显增加，主要是由于箭筈豌豆的介入而使茎叶比显著降低，牧草品质变优。     

A long‐term study of burning effects on a plant pathogen in tallgrass prairie

Tallgrass prairie species have evolved with regular exposure to fire. However, burning has been used as a management tool for reducing plant disease in agricultural systems, posing the question of how plant pathogens of tallgrass prairie would be affected by burning. The rust fungus Puccinia dioicae, infecting Erigeron strigosus (Asteraceae), was studied for 8 years in long‐term experiments to evaluate the effects of burning in native tallgrass prairie. This experiment also allowed evaluation of the effects of nutrient additions, although E. strigosus was rare in the plots with added nutrients in most years. Burning reduced rust severity in most years, but effects from additions of nutrients were rarely observed. There was high interannual variation in rust severity within a location, suggesting that weather may be the most important of these three abiotic factors in determining infection. An analysis of weather variables associated with disease severity found that solar radiation in the month prior to sampling was associated with severity in unburned plots; temperature approximately 2 months prior to sampling was also associated with severity in burned plots. High interannual variation also suggests that the effects of this pathogen on its host would be sporadic and difficult to study in short‐term experiments.     

Starch granule size variation and relationship with tuber dry matter content in heritage potato varieties

Heritage potato varieties in Canada are historic old varieties collected from Canada and various countries before the formal establishment of the Canadian plant variety registration system and may be a valuable gene resource for beneficial traits in potato breeding and bioproducts development. Greater evaluation is the key for the enhanced use of these materials. It is unknown how much variation of starch granules occurs among Canadian heritage potato varieties. We analyzed the starch granule size of 14 potato heritage varieties held in the Canadian Plant Gene Resources collection over 2 years using a squeezed juice and microscopic method recently developed at the Potato Research Centre. The varieties demonstrated considerable variation in starch granule size and shape. The granules showed average lengths ranging from 18 μm in the variety Congo to 32 μm in ‘Russet Burbank’. The largest single granule measured from 64 μm in ‘Congo’ to 91 μm in ‘Crotte d’Ours.’ The granule sizes of the varieties showed a very high correlation (r = 0.975, P < 0.0001) between years. This high reproducibility suggests the existence of genetic factors in determining starch granule size. We also found that the starch granule size is positively correlated with tuber dry matter (in terms of specific gravity) in these heritage potatoes. The results demonstrated reproducible genotypic variation for starch granule size and shape in tubers with a significant correlation to tuber dry matter in these heritage potato varieties, and offers the possibility for and agronomic relevance of genetic modification of starch granules through selective breeding.     

双峰驼精清诱导排卵活性成分的DEAE—纤维素柱层析分离及其生物活性

选用DEAE－纤维素离子交换柱对双峰驼精清进行分离，各层析组分用于大鼠垂体组织体外培养，并给母驼肌注有活性的组分，以RIA法测定垂体组织培养液和母驼血浆中LH及FSH的浓度。结果表明，驼精清经DEAE－纤维素柱分离后可得到5个蛋白组分（L1－L5），其中L3在大鼠垂体培养时引起LH释放明显增加（P＜0．05），FSH则无明显变化。给卵巢上无大卵泡发育的母驼肌注有活性的组分L3，可引起血浆中LH明显升高，FSH也无变化。由此表明，L3在体内外试验中均具有引起LH释放的生物活性，它可能是诱导排卵的活性因子或其成分之一。     

高校教学网络的科学管理

本从NOVELL网常规管理、建立多重配置的无盘工作站、网络的安全运行措施三个方面探讨NOVELL教学网络的科学管理。     

种公鹿茸重性状与年龄相关的统计分析

本文探讨了我国人工选育的双阳梅花鹿和西丰梅花鹿品种、长白山梅花鹿品系、天山马鹿清原品系和乌兰坝东北马鹿等 5个品种品系种公鹿的茸重性状与鹿年龄的关系 ,结果表明 ,在一定年龄段 ,茸重性状与年龄之间呈强正相关并建立了相应的线性回归方程 ,为预测并比较茸鹿种公鹿各年龄时的茸重水平和制定茸重标准及早选种等提供了科学依据     

大兴安岭林区森工采运方式现状及发展趋势研究

本文论述了大兴安岭林区采运方式现状。分析了影响采运方式的因紊。提出了今后的发展方向。