一例鹦鹉绦虫及其肠道组织病理的观察

采用常规尸解,石蜡切片、苏木精-曙红染色（H—E）、绦虫整体醋酸明矶洋红染色等方法’对一只病死蓝眼葵花鹦鹉的绦虫病原及肠道组织病理进行了初步研究。结果表明：该蓝眼葵花鹦鹉肠道内寄生有大量瑞氏绦虫,集结成团堵塞了肠道。肠道组织病理分析发现肠牯膜上皮部分组织坏死、脱落,小肠绒毛固有层、黏膜下层及浆膜内有充血、炎细胞浸润,显示该种绦虫对鹦鹉肠道组织造成了一定损伤,影响了鹦鹅对营养物质的消化吸收。     

Slug control in Australian canola: monitoring, molluscicidal baits and economic thresholds

Exotic slugs have become serious pests of canola, at establishment, in Southern Australian high-rainfall cropping zones. Slugs were monitored using relatively inexpensive 300 mm x 300 mm terracotta tiles acting as refuges. An investigation was made of the effects of the time of application of chelated iron baits on the slug species Deroceras reticulatum Müller and Lehmannia nyctelia Bourguignat. Baits reduced the number of surface-active slug species. A single application at sowing provided greater efficacy than one application before sowing, and efficacy was comparable with that of two applications. Canola seedling densities showed a negative response to D. reticulatum numbers; the presence of even one individual per refuge trap reduced seedling numbers below optimum densities. Thistles and other vegetation were associated with increased numbers of slugs. European guidelines for slug monitoring and damage appear to be at least partly applicable to Australian conditions.     

浙江水稻稻种病原细菌多样性研究

 1997~2000年间对以浙江平原、丘陵及山区为主的稻种病原细菌开展了种类、频率及传病率的研究。从303份稻种样本中分离出3906个菌株,经菌落形态、细菌学、致病性测定后获得201个致病或弱致病菌(占总数的5.15%)。选出致病及非致病代表菌株299个连同23个对照菌株用Biolog进行证实。结果表明种子上所带的病原细菌涉及到6个致病细菌种和5个弱致病种。平原稻区存在较多致病细菌种,山区较少,但两地均以弱致病细菌种占优势;丘陵的强致病细菌种的分离频率显著高于平原与山区。在稻种上携带的11个细菌种中,人工接种和自然感染的病稻种均能引起传病的有Xanthomonas oryzae pv.oryzicola,Pseudomonas fuscovaginae及Acidovorax avenae subsp.avenae.     

Variation in the development of secondary dormancy in oilseed rape genotypes under conditions of stress

Summary A substantial amount of seed is left in the fields before and during harvest of oilseed rape. Although this crop exhibits little or no primary dormancy, the absence of certain environmental cues that promote germination of imbibed seeds induces secondary dormancy. The work reported investigated the extent to which environmental stress conditions, including osmotic stress, low oxygen stress and anaerobiosis, induce secondary dormancy in oilseed rape, and examined the variation in development of secondary dormancy between and within genotypes. Osmotic stress was most effective in inducing dormancy. Anaerobic treatment produced very few dormant seeds, as did an atmosphere low in oxygen and high in nitrogen. The development of secondary dormancy under osmotic stress varied considerably between and within genotypes. Dormancy ranged from almost zero to about 60% for winter genotypes and about 85% for spring types. Within genotypes, variations occurred between seed lots and years of harvest. Temperature variations affected the percentage of dormant seeds. More dormant seeds were likely to be produced with incubation under water stress at 20 °C than at 12 °C. In winter genotypes, fewer dormant seeds were produced when incubation temperature and germination test temperatures differed. Thus, incubating at 20 °C and 12 °C, followed by germination tests at 20 °C and 12 °C, respectively, produced most dormant seeds. Also, in the winter genotypes, the potential development of secondary dormancy was positively correlated with the pattern and speed of germination of untreated seeds.     

黄腐酸抗旱营养剂对小麦和玉米生长的影响

研究了黄腐酸旱地龙拌种、浇灌以及喷施对小麦和玉米生长的影响。结果表明:拌种时间为30 min时可提高小麦的发芽率和促进小麦苗期生长;浇灌试验中,正常供水条件下,浓度为600倍的稀释溶液相比对照可显著降低叶绿素a和类胡萝卜素含量,分别降低17.7%和15.6%;而干旱胁迫下,稀释480倍处理相比对照显著提高叶绿素a含量达24%;浇灌FA可显著提高田间玉米花粒期株高和Chla+b,分别提高7%和17%,喷施处理提高叶片净光合速率和水分利用效率,分别为25%和28%,而浇灌处理提高了62%和45%;浇灌FA显著提高田间小麦苗期和返青期叶绿素含量。     

出口萝卜种子中芸薹生链格孢的分离与鉴定

本文对酒泉出境萝卜种子上发现的链格孢菌(Alternariasp.)进行了形态学和分子生物学鉴定,根据结果,将这种链格孢鉴定为芸薹生链格孢(Alternariabrassicicola);该种病原菌是危害十字花科蔬菜种子生产的世界性病原真菌,在甘肃酒泉繁种基地过去未见报道。     

Over-winter predation of Abutilon theophrasti and Setaria faberi seeds in arable land

To improve understanding of over-winter weed seed predation in arable fields, we used data from winter exclosure trials to determine the amount of predation and the influence of crop habitats on predation of Abutilon theophrasti and Setaria faberi seed in 2-year (maize/soyabean) and 4-year (maize/soyabean/small grain+lucerne/lucerne) crop rotation systems between 2005 and 2008. Crop habitat influenced seed predation, and had similar impacts on the two weed species. Mean A. theophrasti predation ranged from 31% in the 2-year soyabean habitat to 99% in the 4-year lucerne habitat. Mean S. faberi predation ranged from 31% in the 2-year soyabean habitat to 97% in the 4-year lucerne habitat. Results suggest that a combination or interaction of cover and substrate may have affected crop habitat preference by seed predators. Future research should further examine the influence of physical habitat on seed predation to determine characteristics of cropping systems that encourage predation, particularly during over-winter periods, so as to routinely incorporate seed predators into long-term weed management strategies.     

中国帕米尔高原种子植物属的区系研究

中国帕米尔高原座落于新疆西南部,北纬37°-39,°东经73°-76,°面积约30000km2,区内平均海拔约4000m,拥用种子植物963种(包括变种),分属于59科303属,其中裸子植物3科3属12种,被子植物56科300属951种。种子植物属的区系特征如下:1)单种属、少种属占极高的比例,属种比值偏高,植物区系组成复杂,2)属级水平分析表明,本区植物区系以北温带为主的温带成分占主导地位,仅有13个从热带分布区延伸到温带的热带属,且在本区所含种类极少,但丰富了本区植物区系的组成,3)植物区系较为年轻且有一定的衍生性,4)高原生态因子的作用,使本区植物获得了适应寒冷和干旱的特性。     

Effect of temperature and humidity on the longevity of Orobanche seeds

The effects of moisture and temperature on seed longevity were studied over periods of up to 426 days in three species of Orobanche . Saturated salt solutions were used to achieve equilibrium relative humidities (e.r.h.) between 11% and 85% at temperatures of 20–60 °C. The viability equation describing loss of viability in these conditions applied to the three species such that the lower the temperature and lower the equilibrium relative humidity the greater the longevity. The initial viability differed between species with the seed lot of Orobanche crenata having the lowest viability. However, the relative effect of temperature on longevity and the relative sensitivity of seed longevity to changes in equilibrium relative humidity were the same in all species. Longevity, estimated by the standard deviation of the seed survival curves was greater in Orobanche aegyptiaca and O. crenata than in Orobanche minor , being for example about 100, 103 and 49 days, respectively, at 40 °C, 50% e.r.h. Accurate prediction of longevity is necessary to understand and quantify the population dynamics of weeds and will help the farmer to optimize control measures such as solarization. Taken in conjunction with published data on loss of viability of imbibed seeds, the annual loss of viability on a typical Eritrean farm is predicted to be about 38%.