小麦吸浆虫防治适期研究初报

选择不同杀虫剂、不同时期对小麦吸浆虫的防治效果试验表明，在秋季麦播前土壤处理，防效不理想；在吸浆虫蛹期、羽化高峰期防治虽能获得较好的防治效果，但需要专业技术人员掌握发育进度，不适合指导群防群治；而小麦抽穗露脸70％～80％时，正值吸浆虫产卵始盛期，此期防治能获得事半功倍的效果，这一物侯现象群众容易掌握。此前及此后羽化的成虫多为无效虫源。所以，把小麦抽穗露脸70％～80％作为吸浆虫的防治适期符合当前的生产现状。     

柑桔溃疡病综合防治研究

1985-1989年研究结果表明:14%胶氨铜水剂是目前防治柑桔溃疡病较理想的杀菌剂,效果略超过常规农药波尔多液;溃疡病药剂防治适期是春、夏、秋梢的梢长分别为4-5、6-7、5-6cm时,以及果实横径为0.8-1.0、1.8-2.0、2.8~3.0cm时。重病园用单一防治措施无法奏效,综合防治可有效地降低发病程度,提高果实产量、品质及增加经济效益。     

Inheritance of resistance in carnation against Fusarium oxysporum f.sp. dianthi races 1 and 2, in relation to resistance components

Four carnation cultivars, Novada (resistant to races 1 and 2 ofFusarium oxysporum f.sp.dianthi), Elsy (susceptible to race 1), Lena (susceptible to race 2) and Sam's Pride (susceptible to both races), were selfed and crossed. When three months old, the seedlings were inoculated via the roots or via the stems, after which wilting was recorded weekly according to a 5-point ordinal scale.Analyses were carried out on the proportions of diseased plants. For race 1 variation between the progenies could be described by means of general combining abilities only; GCA values were not affected by the inoculation method used. Also for race 2 GCAs were most important but the GCA values appeared different for the two inoculation methods. It is concluded that resistance to both races is inherited in an additive way.Indications for independently inherited root-specific resistance components (extravascular resistance) were only found with race 2. With both races, the ability to confine the pathogen at the infection site appeared the most important resistance component. Resistant progenies were also characterized by longer latent periods and lower wilting rates.Both race 1 and race 2 induced the accumulation of the phytoalexins dianthalexin and methoxydianthramide S, but race 2 induced higher amounts than race 1. The accumulation of phytoalexins was positively correlated to the resistance level of the progenies against the respective races. The progenies of the double-resistant cultivar Novada appeared to produce particularly high levels of phytoalexins.     

饲粮L-精氨酸含量对冬毛期雌性水貂氨基酸消化率、血清氨基酸含量及血清生化指标的影响

本试验旨在研究饲粮L-精氨酸含量对冬毛期雌性水貂氨基酸消化率、血清氨基酸含量及血清生化指标的影响。选取(150±3)日龄的健康雌性水貂63只,随机分为7组(每组9个重复,每个重复1只水貂),分别饲喂在基础饲粮中添加0、0.20%、0.40%、0.60%、0.80%、1.00%和1.20%L-精氨酸的试验饲粮,试验饲粮中L-精氨酸含量分别为1.70%、1.90%、2.10%、2.30%、2.50%、2.70%和2.90%。预试期7 d,正试期60 d。结果表明:1)干物质采食量、干物质排出量和干物质消化率各组之间差异不显著(P0.05)。2)1.70%组水貂的赖氨酸消化率显著高于2.50%、2.70%和2.90%组(P0.05)。2.70%和2.90%组水貂的精氨酸消化率显著高于1.70%和1.90%组(P0.05)。3)2.30%组水貂血清丝氨酸和脯氨酸含量显著高于1.70%、1.90%、2.10%和2.90%组(P0.05)。2.30%和2.50%组水貂血清丙氨酸含量显著高于1.70%、1.90%、2.10%和2.90%组(P0.05)。2.30%组水貂血清苯丙氨酸含量显著高于1.70%和2.90%组(P0.05)。2.30%组水貂血清精氨酸含量显著高于1.70%、1.90%、2.10%和2.90%组(P0.05)。4)2.30%组水貂血清天门冬氨酸氨基转移酶活性显著高于1.70%组(P0.05)。2.30%和2.50%组水貂血清乳酸脱氢酶活性显著高于1.70%、1.90%、2.10%、2.70%和2.90%组(P0.05)。5)2.30%和2.50%组水貂血清免疫球蛋白M含量显著高于1.70%、1.90%、2.10%、2.70%和2.90%组(P0.05)。2.30%组水貂血清免疫球蛋白G含量显著高于1.70%和2.90%组(P0.05)。2.30%和2.50%组水貂血清补体4含量显著高于1.70%和2.90%组(P0.05),2.10%组水貂血清补体4含量显著高于1.70%(P0.05)。由结果可知,当饲粮中L-精氨酸含量为2.30%时,冬毛期雌性水貂能获得较好的蛋白质和氨基酸代谢,同时免疫功能得到增强。     

Effects of grass forage species and long‐term period of low quality forage diet feeding on growth performance,nutrient utilization and microbial nitrogen yield in growing wether lambs

Six growing lambs were used to evaluate the feeding value of two forage‐based diets in a long‐term feeding period by measuring body weight (BW) gain, digestibility, nitrogen (N) retention and microbial N (MBN) yield. The animals were fed imported low‐quality timothy hay (TH) with concentrate diet (THD) or imported low‐quality Italian ryegrass straw (IR) with concentrate diet (IRD) for 9 months. The forages were offered at 2% BW, and concentrate was fed at 40% of forage intake. The BW gain averaged 82.6 and 66.2 g/day for THD and IRD, respectively, without showing significant difference. Average forage intake (% BW) was significantly greater for IR than for TH, although it was not affected by feeding periods. The digestibility did not differ between diets or periods. The numerically greater (P = 0.06) ratio of retained N to absorbed N for IRD than that for THD was prominent. Neither diet nor period had significant effect on MBN supply and efficiency of MBN synthesis. The results suggest that the IR‐based diet can be also used for long‐term periods of feeding to growing ruminant animals as a grass hay‐based diet without any detrimental effects on nutrient utilization and growth performance.     

A revision of Billing's potential doublings table for fire blight prediction

In her fire blight prediction systems, E. Billing (1978, in: P.R. Scott & A. Bainbridge (Eds), Plant disease epidemiology, p. 159–166) has used the parameter potential doublings per day (PD) of the fire blight causing bacterium,Erwinia amylovora. Reconsideration of her calculations of PD revealed, however, that the PD values in Billing's table were underestimated. This leads to overestimation of the duration of incubation periods. A corrected PD table is presented. Sensitivity analyses indicated that day-of-the-year and latitude have little effect on the values in the PD table.Samenvatting Billing maakte in haar systemen waarin de ontwikkeling van bacterievuur wordt voor-speld, gebruik van de parameter potentiële verdubbelingen per dag (=PD) van de bacterievuur veroorzakende bacterieErwinia amylovora. Uit herberekeningen blijkt echter, dat de PD-waarden in Billings tabel onderschat worden. PD-onderschattingen leiden in haar systemen tot overschattingen van de duur van incubatieperioden. Een gecorrigeerde PD-tabel werd samengesteld. Uit gevoeligheidsanalyses bleek dat de dag van het jaar en de breedtegraad een gering effect hebben op de waarden in de PD-tabel.     

大脑优势与第二语言习得

本文回顾了二十多年来神经语言学领域的重要研究,结合第二语言习得的有关研究,得出了与“临界期”假说完全不同的看法:成人与儿童(五岁以上)在第二语言习得过程中大脑神经因素没有区别性差异。     

黄体期和卵泡期小尾寒羊DIO2与DIO3组织表达

为分析DIO2和DIO3基因在小尾寒羊不同繁殖时期(黄体期和卵泡期)下丘脑-垂体-性腺轴各组织中的表达差异,阐明这2个基因在绵羊发情转换中的表达模式,实验采用实时荧光定量PCR(Real-time PCR)技术对比分析DIO2和DIO3基因在黄体期和卵泡期小尾寒羊下丘脑-垂体-性腺轴各组织中的表达差异。结果表明:DIO2和DIO3基因在下丘脑、垂体、松果体、大脑、小脑、卵巢、子宫、输卵管、肾脏、肾上腺10种组织中均表达;DIO2基因在黄体期和卵泡期的垂体组织中表达量显著高于其他组织(P<0.05),其中黄体期垂体、子宫、下丘脑、松果体、输卵管和卵巢DIO2的表达量显著高于卵泡期(P<0.05);DIO3在卵泡期松果体、下丘脑、子宫、垂体和输卵管的表达量显著高于黄体期(P<0.05)。综上,DIO2能抑制绵羊发情,而DIO3促进发情。     

罗曼褐父母代产蛋前期产蛋规律的分析

对1249只健康的23周龄的罗曼褐父母代种母鸡的产蛋情况进行观察,试验期67 d(至32周龄),目的在于了解产蛋前期,蛋用种鸡产蛋性能的变化规律。试验结果表明,随鸡群日龄的增大蛋壳颜色逐渐变浅,产蛋率和种蛋合格率逐渐上升,鸡群的死淘率在开始人工授精的前2周最高,双黄蛋率随产蛋率的上升而逐渐减小,双黄蛋平均重随产蛋率上升逐渐增大,到产蛋率达最高峰时开始变小,软壳蛋率和破蛋率随鸡群日龄的增大而逐渐减小,总蛋重及种蛋平均重随鸡群日龄的增大而逐渐增大。