模拟降雨条件下谷子和冬小麦植株对降雨再分配过程的影响

以谷子（ Setaria italica）、冬小麦（ Triticum aestivum Linn 。）为研究对象,利用人工模拟降雨测定了不同降雨强度和生长阶段两种作物植株的穿透雨,采用人工喷雾法测定了不同生长阶段的冠层截留,根据水量平衡法计算了不同观测阶段的茎秆流。结果表明：谷子、冬小麦冠层对降雨的再分配作用显著,谷子冠下穿透雨率平均约为79％,茎秆流率平均约为20％,冠层截留率平均约占1％;冬小麦冠下穿透雨率平均约为79％,茎秆流率平均约为19％,冠层截留率平均约占2％。在其全生育期内,两种作物冠下穿透雨与茎秆流呈彼此消长趋势。穿透雨量和茎秆流量与降雨强度呈显著正相关关系,但是穿透雨率和茎秆流率与降雨强度的关系不显著。茎秆流量和冠层截留量及其二者占总降雨量的比率均与作物叶面积指数呈显著正相关关系,但穿透雨量及穿透雨率随叶面积指数增加呈显著下降趋势。     

出芽短梗霉菌菌株PA-2的除草活性及对作物的安全性

从青海省平安县发病杨树叶片上分离得到菌株 PA-2,其发酵滤液对多种阔叶杂草表现出较好的除草活性。对该菌株的培养特征和16S rDNA基因序列分析后,确定其为短梗霉属出芽短梗霉菌Aureobasidium pullulans。盆栽试验表明,其发酵滤液对供试阔叶杂草猪殃殃、藜、冬葵、酸模叶蓼及禾本科野燕麦的鲜重防效分别达到87.25%、78.46%、82.25%、62.11%、80.27%。作物安全性试验结果表明,其发酵滤液对小麦、蚕豆、青稞很安全,对油菜、豌豆有轻微影响。综上所述,菌株 PA-2具有作为微生物除草剂的开发潜力。     

桑天牛的生物学特点及其防治技术概述

桑天牛为杨树等林木重要蛀干害虫,在我国大部分地区广泛分布,且其防治是一个世界性的难题,通过对桑天牛在生物学特性、防治方法与技术等方面的研究进展进行综述,为桑天牛的综合治理提供参考。     

坡柳皂苷对大菜粉蝶生长发育的抑制活性

采用浸渍叶碟饲喂法测定了坡柳皂苷对大菜粉蝶的生物活性。结果表明:用500、1 625、2 750、3 875和5 000μg/mL的坡柳皂苷处理24 h后,对大菜粉蝶4龄幼虫生长发育的抑制率分别为14.47%、31.54%、49.70%、62.48%和79.94%,处理48 h后的抑制率分别为2.72%、39.26%、54.82%、70.53%和86.39%;坡柳皂苷对大菜粉蝶4龄幼虫具有显著的拒食活性,供试5种浓度下处理24 h后,拒食率分别为30.21%、40.62%、54.33%、72.47%和84.84%,48 h后的拒食率为4.4%~86.67%;5 000μg/mL处理14 d后,幼虫化蛹率为32%,显著低于对照组(72%);供试5种浓度坡柳皂苷处理23 d后,蛹的羽化率分别为56%、44%、44%、36%和32%,均低于对照组(64%)。研究表明,坡柳皂苷对大菜粉蝶生长发育、取食及化蛹均有明显的抑制作用。     

Biology and management of the fast‐emerging threat of broomrape in rapeseed–mustard

Broomrapes (Phelipanche and Orobanche spp.) are obligate root parasites of the family Orobanchaceae. The natural variation in Orobanchaceae exists in plants involving Triphysaria versicolor (facultative hemiparasite), Striga hermonthica (obligate hemiparasite) and Phelipanche aegyptiaca, formerly Orobanche aegyptiaca (holoparasite). The family Orobanchaceae has 90 genera. The four major parasitic species of broomrape are Phelipanche ramosa in the Brassicas, especially in rapeseed, Phelipanche cernua in tobacco and sunflower, P. aegyptiaca in solanacious crops and in Brassica juncea and Phelipanche crenata in leguminous crops. They are prevalent, infesting nearly 1.2% of the world's arable land. In India, P. ramosa and P. aegyptiaca cause severe infestations of Brassica and have threatened its cultivation in major growing areas. In addition, a single broomrape plant can release >100 000 seeds that remain viable for decades in the soil. This provides the parasite with a great genetic adaptability to environmental changes, including host resistance, agronomical practices and herbicide treatments. Different control measures, such as manual weeding, herbicide applications, solarization, crop rotation and integrated broomrape management practices, have been proposed in order to reduce the broomrape menace and improve yields in farmers' fields. Breeding for broomrape resistance also could be an economic, feasible and environmental friendly control method. The present article reviews the current status of research on broomrape in India and abroad, as well as suggests strategies for its effective management.     

昆明犬胎儿成纤维细胞系的建立及生物学特性分析

本研究旨在探索和建立昆明犬胎儿成纤维细胞体外分离、培养的技术方法并观察其生物学特性.试验利用剖腹手术法获得发育30 d的昆明犬胎儿12个,性别鉴定结果为7公5母.公、母胎儿体尺和体重分别为:体长1.90 cm±0.14 cm和2.00 cm±0.05 cm,体宽0.90 cm±0.13 cm和0.90 cm±0.15 cm;体重0.68 g±0.17 g和0.66 g±0.06 g,差异均不显著(P>0.05).以昆明犬胎儿组织为材料,采用胶原酶消化法和细胞冷冻保存技术建立了昆明犬胎儿成纤维细胞系,并对所构建的细胞系进行生物学特性研究.结果表明,分离的胎儿成纤维细胞呈典型的成纤维细胞形态,生长曲线呈S型,倍增时间约为36 h;冻存前和复苏后的存活率分别为96.1%和94.6%;染色体核型分析显示2n=78(XY),并在体外培养多代后仍能保持正常核型.本研究建立的昆明犬胎儿成纤维细胞系可在体外快速贴壁生长、增殖,进行稳定培养,这不仅使昆明犬遗传资源在细胞水平得以保存,且所获成纤维细胞能作为相关研究中所需细胞的来源.     

重组植物乳杆菌生物学特性比较研究

试验对植物乳杆菌(Lactobacillus plantarum,Lp)出发菌与携带绿色荧光蛋白(green fluorescent protein,GFP)标记基因的重组植物乳杆菌(Lp-GFP)生物学特性进行了详细的比较研究,以便于深入开展益生菌植物乳杆菌在动物肠道内分布和定植规律的研究。结果显示,Lp和Lp-GFP生长曲线的变化趋势基本相同,其中Lp-GFP的生长速度略有滞后;Lp和Lp-GFP最适培养温度均为37 ℃,最适初始pH均为6.5;Lp和Lp-GFP耐高温、耐人工胃液、耐人工肠液和耐胆盐的特性趋势一致;Lp和Lp-GFP的抑菌特性无显著差异(P>0.05);除了红霉素,Lp和Lp-GFP对其他药物的敏感性基本没有发生变化。综上所述,植物乳杆菌的重组对其生物学特性没有显著的影响,这为重组标记菌株的后续培养和机理研究奠定了重要基础。     

Impacts of mowing and bud destruction on Centaurea solstitialis growth,flowering, root dynamics and soil moisture

Centaurea solstitialis (yellow starthistle) has invaded rangelands and natural areas in the western USA. There is evidence that mowing is a more effective method of reducing growth and seed production, compared with the well‐established and distributed bioagents. To test this hypothesis we measured C. solstitialis's growth and reproduction following two treatments (late spring and early summer bud/capitula destruction and shoot mowing) and measured C. solstitialis's growth and reproduction. We measured changes in soil moisture content to test the hypothesis that these manipulations differentially affect water usage by the invasive plant. Mowing produced shorter plants that weighed less. Bud damaged plants were not statistically different from untreated controls. The number of developed capitula was reduced 67% by mowing but was unaffected by bud damage. Mowed plants redistributed resources from root to flower production. Both treatments reduced mean capitulum diameter. This resulted in reductions of 76% and 21% in estimated seed number for mowed and bud damaged plants respectively. Root abundance decreased and root life‐span was reduced by both treatments. Soil moisture depletion was greatest from mid‐May to mid‐July (from 21% to 9%) and occurred after maximum root abundance. Mowing resulted in a delay in soil moisture depletion compared with the bud damaged plants or the untreated controls. Bud/capitula damage did not affect C. solstitialis's requirement for soil water. Overall, this study supported the hypothesis that mowing reduced C. solstitialis growth and reproduction more than bud damage alone. This information will aid managers in selecting a strategy for managing C. solstitialis in a particular habitat.     

亚致死浓度氯虫苯甲酰胺对小菜蛾生物学特性的影响

探讨亚致死剂量氯虫苯甲酰胺对小菜蛾3龄幼虫的亚致死效应,为氯虫苯甲酰胺的合理使用提供依据。采用叶片药膜法测定亚致死剂量氯虫苯甲酰胺对小菜蛾3龄幼虫生物学特性的影响。结果表明:与对照相比,亚致死浓度的氯虫苯甲酰胺处理后,小菜蛾4龄龄期和蛹期明显延长,化蛹率、羽化率、单雌产卵量明显降低。另外蛹重也明显低于对照。这表明亚致死剂量氯虫苯甲酰胺对小菜蛾种群增长有一定抑制作用,对小菜蛾综合防治策略的制定有积极意义。     

Effects of artificially cultivated biological soil crusts on soil nutrients and biological activities in the Loess Plateau

Biological soil crusts （BSCs） play an important role in the early succession of vegetation restoration in the Loess Plateau, China. To evaluate the effects of artificially cultivated BSCs on the soil surface micro-envir- onment, we obtained natural moss crusts and moss-lichen crusts from the Loess Plateau of Shaanxi province, and subsequently inoculated and cultivated on horizontal and sloping surfaces of loess soil in a greenhouse. The chemical and biological properties of the subsoil under cultivated BSCs were determined after 10 weeks of cul- tivation. The results indicated that BSCs coverage was more than 65% after 10 weeks of cultivation. Moss crust coverage reached 40% after 5 weeks of cultivation. Compared with the control, soil organic matter and available nitrogen contents in moss crust with the horizontal treatments increased by 100.87% and 48.23%, respectively; increased by 67.56% and 52.17% with the sloping treatments, respectively; they also increased in moss-lichen crust with horizontal and sloping treatments, but there was no significant difference. Available phosphorus in cultivated BSCs was reduced, soil pH was lower and cationic exchange capacity was higher in cultivated BSCs than in the control. Alkaline phosphatase, urease and invertase activities were increased in artificially cultivated BSCs, and alkaline phosphatase activity in all cultivated BSCs was obviously higher than that in the control. Numbers of soil bacteria, fungi and actinomycetes were increased in the formation process of cultivated BSCs. These results indicate that BSCs could be formed rapidly in short-term cultivation and improve the mi- cro-environment of soil surface, which provides a scientific reference for vegetation restoration and ecological reconstruction in the Loess Plateau. China.