我国特有植物一木里香橼叶精油化学成分的研究

用气相色谱保留指数定性法、色谱-质谱-计算机联用测定和标准品迭加法分析了木里香橼叶精油的化学成分。从分离出的59个色谱峰中鉴定了31个化合物。其中主要成分是柠檬烯(31.730％)、芳樟醇(1.554％)、香茅醛(23.383％)、香茅醇(1.189％)、橙花醇(11.777％)、香叶醛(16.544％),乙酸香茅酯(1.427％)、乙酸橙花酯(2.258％)、乙酸香叶酯(4.714％)等。把木里香橼叶油与木里香橼果皮油与云南野香橼叶油分别作了比较。结果表明木里香橼叶油中含氧化合物醇、醛、酯的含量相当高,是精油的主要成分,可能作为进口橙叶油的较好的代用品,是一种很有潜力的天然香料资源。     

Resistance to Meloidogyne spp. in Allohexaploid Wheat Derived from Triticum turgidum and Aegilops squarrosa

Expression of resistance to Meloidogyne incognita and M. javanica from Aegilops squarrosa was studied in a synthetic allohexaploid produced from Triticum turgidum var. durum cv. Produra and Ae. squarrosa G 3489. The reproductive rate of different races of M. incognita and M. javanica, expressed in eggs per gram of fresh root, was low (P < 0.05) on the synthetic allohexaploid and the resistant parent, Ae. squarrosa G 3489, compared with different bread and durum wheat cultivars. Reproduction of race 2 and race 3 of M. incognita and an isolate of M. javanica was studied on the synthetic allohexaploid and seven cultivars of T. aestivum: Anza, Coker 747, Coker 68-15, Delta Queen, Double Crop, McNair 1813, and Southern Bell. The latter six cultivars are grown in the southeastern United States and reportedly were resistant to M. incognita. Significant differences (P < 0.05) were detected in nematode reproduction on the seven bread wheat cultivars. Reproduction of M. incognita race 3 and M. javanica was highest on Anza. Reproductive rates on the six southeastern United States bread wheat cultivars varied both within and among nematode isolates. The lowest reproductive rates of the three root-knot isolates were detected in the synthetic allohexaploid.     

川西云杉几丁质酶基因PlCHI的克隆、表达与生物信息学分析

以川西云杉（Picea likiangensis var.balfouriana（Rehd.et Wils.）Hillier ex Slsvin）为材料,利用RT-PCR技术,克隆获得几丁质酶基因PlCHI的cDNA全长序列,并对该基因的序列特征及基因表达情况进行分析。结果显示,PlCHI的开放阅读框长1017 bp,共编码338个氨基酸;蛋白序列结构域分析结果表明,PlCHI为ClassⅠ类几丁质酶,属19家族,兼具溶菌酶活性;该序列与其他植物几丁质酶的蛋白序列相似性较高。系统发育分析结果显示,川西云杉PlCHI序列与北美云杉（Picea sitchensis（Bong.）Corr.）、黑松（Pinus thunbergii Parl.）等松科植物亲缘关系最近。进一步将PlCHI重组质粒转入大肠杆菌BL21（DE3）中,表达出约45 kD的蛋白,主要以包涵体形式存在,且在25℃下采用0.2 mmol/L的IPTG诱导4 h时蛋白的表达量最佳。     

黄曲霉群菌种产生黄曲霉毒素B_1的调查研究

本文对来自我国20个省、市、自治区的不同基物上分离的和中国科学院微生物研究所菌种保藏室以及其他单位提供的黄曲霉群菌种,经随机选取82株进行了黄曲霉毒素B_1的测定,证明在测试的9个已知分类群中产生黄曲霉毒素B_1的菌种只限于寄生曲霉和黄曲霉,另外4株种名未定者也能产生此种毒素。在黄曲霉中产毒菌株约占30％(28.3％),其在GAN(葡萄糖硝酸铵)和大米培养基中的黄曲霉毒素B_1的最高产量分别为133,333.3和160,000.0ppb。总的来说,大体上可以反映在我国一般基物上黄曲霉产毒菌株存在的现状。在实验过程中,还对黄曲霉群菌种在GAN和大米培养基中黄曲霉毒素B_1的产量和产毒菌株数作了比较。发现在大米培养基中黄曲霉毒素B_1的产量高于GAN,而且测试的黄曲霉产毒菌株在这两种培养基中均各有不能产毒的菌株,因此,在测定产毒菌株时,若仅采用其中一种产毒培养基,往往会有漏掉产毒菌株的可能性。     

Auxospore formation inLicmophora (Bacillariophyta)

InLicmophora gracilis var.anglica two auxospores are produced per pair of mother-cells, through the allogamic fusion of migratory and stationary gametes. Both active gametes are produced from the same mother-cell and hence both zygotes are formed in the other mother-cell. Pairing can occur between two stalked cells, or between a stalked cell and a detached cell; in the latter case the migratory gametes derive from the detached cell. The auxospores expand parallel to one another and to the apical axis of the donor mother-cell. Behavioural anisogamy of this kind, which may be termed thecis-type, seems to be characteristic of most araphid pennates and contrasts with thetrans-type exhibited byCymbella, Gomphonema and some other raphid taxa, where each mother-cell produces one migratory and one stationary gamete.     

中国疱脐衣属的新种与新资料

本文报道了中国疱脐衣属四个新分类单位,其中包括三个新种:华东疱脐衣(Lasallia sinorientalis Wei),大理疱脐衣(L.daliensis Wei),苍山疱脐衣(L.caeonshanensis Wei)及东亚疱脐衣一新变种:樊净山变种(L.asiae-orientalis var.fanjingensis Wei)。此外,还从东亚疱脐衣的模式标本中首次发现了该种的子囊盘,并作了补充描述。作者认为,根据有关中国地衣区系的现有知识,迄今尚未发现分布于中国的疱脐衣(Lasallia pustulata(L.)Merat)。而华东疱脐衣可能是疱脐衣在亚洲的地理替代种。     

中国菊科植物上拟盘梗霉属的新种和新组合

拟盘梗霉属(Bremiella G.W.Wilson)霜霉,全世界已报道2个种。本文报道寄生于我国菊科植物上的1个新种及2个新组合。新种是寄生于茼蒿上的Bremiella multiformis Tao et Y.Qin sp.nov.。新组合是欧茼蒿上的Bremiella chrysanthemi-coronarii(Sawada)Tao comb.nov。及黄花蒿上的Bremiella artemisiae-annuae(Ling et M. C.Tai)Tao comb.nov.。对新种作了汉文及拉丁文描述,并附有形态图,还讨论了新种和新组合与近似种之间的区别。     

中国菊科植物上拟盘梗霉属的新种和新组合*

拟盘梗霉属(Bremiella G.W.Wilson)霜霉,全世界已报道2个种。本文报道寄生于我国菊科植物上的1个新种及2个新组合。新种是寄生于茼蒿上的Bremiella multiformis Tao et Y.Qin sp.nov.。新组合是欧茼蒿上的Bremiella chrysanthemi-coronarii(Sawada)Tao comb.nov。及黄花蒿上的Bremiella artemisiae-annuae(Ling et M. C.Tai)Tao comb.nov.。对新种作了汉文及拉丁文描述,并附有形态图,还讨论了新种和新组合与近似种之间的区别。     

Effects of sowing date and volunteers on the infectivity of soil infested with Gaeumannomyces graminis var. tritici and on take-all disease in successive crops of winter wheat

In a field experiment on winter wheat, take‐all on plants and the infectivity of the soil were studied in crop sequences with different combinations of sowing dates. Take‐all was negligible in the first wheat crop, but thereafter the mean disease intensity (measured using a take‐all rating, TAR, with a maximum of 300) was 108, 190, 118 and 251 in the second to fifth successive crops. In each growing season, the disease differed amongst sequences and built up more rapidly and was more intense on plants sown in mid‐September than on plants sown in mid‐October. In late‐sown plots, where volunteers had been present during the mid‐September to mid‐October period, take‐all reached an intensity intermediate between that in early‐sown plots and that in late‐sown plots that had been kept free of volunteers. Volunteers, therefore, partially offset the expected beneficial effect of decreased disease with later sowing. Differences in take‐all amongst sequences were most pronounced in the second wheat crop and early sowing of the previous wheat increased intensity of disease. In the following (third) crop, differences in disease intensity amongst sequences were smaller. Soil infectivity (measured by seedling bioassay after harvest) built up progressively from a low level after the first crop to peak after the third crop. In this build‐up phase, soil infectivity estimates were always numerically greater after harvest of early‐sown treatments than after later‐sown treatments, although never significant at P= 0.05. The greatest difference (P= 0.06) was recorded in October before sowing of the third crop, where the comparison was between soil after two previous early sowings and soil after two previous later sowings and control of volunteers. In the same autumn, presence of green cover (i.e. volunteers) was associated with a smaller loss of soil infectivity between harvest and later sowing than occurred in an absence of green cover. In 2^nd–4^th crops, where comparisons were available and mean TARs indicated moderate levels of take‐all, sowing later had no yield benefit, despite more take‐all and greater soil infectivity associated with early sowing. Important considerations for the management of crops at risk of take‐all are 1) choosing appropriate sowing dates to minimize take‐all or to encourage take‐all decline and 2) controlling volunteers and weed hosts where crops are sown late to minimise take‐all.     

PATHOGENICITY OF METARHIZIUM ANISOPLIAE VAR. ACRIDU TO THE DEVEOLPMENTAL STAGES OF BROWN PLANTHOPPER NILAPARVATA LUGENS STÅL AND SOGATELLA FURCIFERA (HORVATH)

Abstract  The susceptibility and virulence of entomopathogenic fungus Metarhizium anisopliae var. acridum to the stages of brown planthopper (BPH), Nilaparvata lugens (Stål) and whitebacked planthopper (WBPH), Sogatella furcifera (Horvath) were investigated under laboratory conditions. Three dosages of M. anisopliae var. acridum ranging from 10.5, 116.3 and 1027.1 conidial/mm² were used in the experiment. The tested stages of host included three developmental stages, young nymphs (1–2 instars), old nymphs (3–5 instars) and adults. It was found that all tested stages of the planthoppers were susceptible to the fungal infection. The degree of virulence LT₅₀ of M. anisopliae var. acridum against young nymphs of N. lugens are >21, 20.82 and 16.55, respectively with the 3 dosages, the LT₅₀ of the fungus against the old nymphs are 17.68, 15.49 and 13.98, respectively with the 3 dosages; the LT₅₀ of the fungus against the adults are 17.10, 12.57 and 9.14 respectively with the 3 dosages. The degree of virulence LT₅₀ of M. anisopliae var. acridum on young nymphs of S. furcifera are >21, 17.29 and 13.13, respectively with the 3 dosages _; the LT₅₀ of the fungus against the old nymphs are 16.94, 15.02 and 13.03, respectively with the 3 dosages; the LT₅₀ of the fungus against the adults are 12.78, 10.16 and 7.64, respectively with the 3 dosages. Adults were more susceptible to M. anisopliae var. acridum infection than their nymphs and the young nymphs were most resistant to the fungal infection. The cumulative mortality of each stage was dosage-dependent. Of all the developmental stages, WBPH was more susceptible than BPH to M. anisopliae var. acridum infection with the same dosages.