假单胞杆菌B301对稻瘟病菌的拮抗性

B301是一株分离自空气中的假单胞杆菌（Pseudomonas sp.)。室内测定表明,它能抑制稻瘟病菌的分生孢子萌发和菌丝生长。病菌分生孢子在B301发酵液的2倍稀释液中完全不能萌发,40倍稀释液中的萌发率为35.58%,比对照下降59.4%。B301发酵液稀释140倍时,对病菌菌丝生长的抑制率为52.1%,其抑制菌丝生长的最大稀释度为4480倍。B301发酵液中的抗菌物质具有较强的耐热性,在80℃下,60min仍保持原有活性,但当温度上升到100℃后则不稳定,10min内活性显著下降,80min后完全失活。田间防治试验表明,B301发酵液防治稻瘟病的效果为45％左右,与对照药剂20％三环唑可湿性粉剂500倍液防效相当。此外,B301还能有效抑制棉花炭疽病菌和玉米小斑病菌的生长。     

Qualitative resistance of Hevea to Phyllachora huberi P. Henn

Qualitative observations of Hevea spp. resistance to Phyllachora huberi were carried out on 200 clones in a collection and 21 full-sib progenies under natural conditions of infestation. A total of 42 clones, mostly originating from the natural range of the Hevea genus, and at least two species (H. brasiliensis and H. benthamiana) revealed total resistance to the parasite. For nine of the thirteen `resistant ×susceptible' and `resistant × resistant' progenies studied, the ratio of susceptible: resistant plants suggested the existence of a total resistance mechanism produced by a dominant allele at a single locus for the P. huberi race(s) present at the study site. For three of the progenies involving the same resistant parent, it was possible to locate the gene (called Phr) at 14.7 cm from the adhisozyme locus. This revised version was published online in July 2006 with corrections to the Cover Date.     

A mutant of Brassica napus with increased palmitic acid content

An induced mutant from European winter oilseed rape with increased palmitic acid content was phenotypically characterized and genetically analysed. The mutant showed a palmitic acid content of 9.2% compared with 4.5% in the parental cultivar. The oleic acid content decreased from 61.6% to 44.2%, whereas the linoleic and linolenic acid contents increased. The mutant plants grew poorly and their seed oil content was only 31.2% compared with 42.8% in the parental cultivar. The inheritance of the mutant was oligogenic and determined by at least four genes. In the F₂ generation, palmitic acid content was negatively correlated with oil content. This mutant may be useful to improve understanding of the genetic regulation of storage lipid synthesis, but has no immediate value for oilseed rape improvement.     

Powdery mildew resistance in Czech and Slovak barley cultivars

Fifteen powdery mildew resistance genes and the gene MlaN81 derived from ‘Nepal 81’were found in 76 Czech and Slovak spring and winter barley cultivars when tested for reaction to a set of powdery mildew isolates. Nine cultivars (‘Donum’, ‘Expres’, ‘Jubilant’, ‘Orbit’, ‘Primus’, ‘Progres’, ‘Stabil’, ‘Vladan’ and ‘Zlatan’) are composed of lines with different resistance genes. The Mlat gene is present in nine cultivars and was transferred from the Anatolian landrace ‘A‐516′. The resistances derived from ‘KM‐1192’and ‘CI 7672’were identical and designated Ml(Kr). Five winter barley cultivars possess the Ml(Bw) resistance. The winter barley line ‘KM‐2099’carries the mlo gene. The parental cultivar ‘Palestine 10’was also tested in which the genes Mlk1, MlLa were identified. The German cultivar ‘Salome’, a parent of seven cultivars tested, probably carries the gene MlLa in addition to mlo and Mla7. The gene mlo6 may be present in the cultivar ‘Heris’. Most of the results were confirmed by the pedigrees of the cultivars.     

鸟胃线虫属一新种记述(旋尾目:旋尾科)

本文记述寄生于红嘴相思鸟[Leiothrixlutea(scopoli)]肌胃的一线虫新种。新种特征:缺侧翼,具粗大环纹,雄虫尾部腹面复盖盾片和大小相等的尾翼,尾乳突排列对称且肛后乳突特大,引带铲形,有别于其他种。     

温度对莲雾毒蛾实验种群影响的研究

通过室内饲养观察,测定了不同温度下莲雾毒蛾卵、幼虫和蛹的发育历期、发育速率、发育起点温度和有效积温;测定了不同温度下莲雾毒蛾各虫态的存活状况,并就卵孵化率、幼虫存活率、蛹羽化率、产卵量和种群趋势指数等指标与温度的关系进行相关性分析。结果表明,莲雾毒蛾世代发育起点温度为9.83℃,有效积温为810.48日度;该虫卵孵化率、幼虫存活率、产卵量与温度的关系均能较好的拟合抛物曲线,其回归关系分别为:SE=-7.7966+0.7612X-0.0164X2;SL=-0.0067X2+0.3053X-3.0686和E=-6.7819X2+310.66X-3197.2。      

谢君魔芋染色体数目的观察研究

（云南农业大学魔芋研究所,云南昆明 650201）     

Investigating the in situ degradation of atrazine in groundwater

This study focused on whether or not atrazine could be degraded by indigenous groundwater bacteria as part of an in situ remediation approach. Groundwater was taken from an unconfined middle upper chalk site where concentrations of atrazine and nitrate were typically in the ranges 0.02-0.2 microg litre-1 and 11.6-25.1 mg NO3-N litre-1 respectively. Sacrificial batch studies were performed using this groundwater spiked with atrazine at a concentration of 10 microg litre-1 in conjunction with a minimal mineral salts liquid (Glu-MMSL) medium which contained glucose as the sole carbon source. Treatments comprised either the Glu-MMSL groundwater cultured bacteria or Pseudomonas sp. strain ADP. Results from sacrificial batches indicated the occurrence of bacterial growth and denitrification as monitored by optical density (absorbance at 600 nm) and NO3-N content. Analysis of atrazine content by solid phase extraction coupled with high-performance liquid chromatography showed no degradation of atrazine over a period of 103 days in either treatment. These results indicated that no acclimatised bacterial community featuring positive degraders to the herbicide atrazine had become established within this chalk aquifer in response to the trace levels encountered.     

降解β-胡萝卜素葡萄球菌的化学合成培养基研究

以沙棘汁中分离的降解β胡萝卜素葡萄球菌为材料,在完全合成培养基中采用单一成分缺失的方法确定了菌体生长的营养需求,试验结果表明,精氨酸、亮氨酸、色氨酸、苏氨酸、丰胱氨酸、脯氨酸6种氨基酸和K2HPO4和NaNO3两种无机盐是必需营养素,其他组分或是对菌体生长没有作用,或是尽管对菌体生长有一定的作用,但缺失时对菌体生长不会受到较大影响。     

假单胞菌HYS菌株对油菜种子发芽的影响

为了研究假单胞菌HYS菌株及其上清液对油菜种子发芽的作用,采用LB培养假单胞菌HYS菌株,分别用水(CK)、LB和HYS菌液浸种油菜种子或在油菜发芽过程中分别添加这3种液体。结果表明,HYS菌液浸种不影响油菜种子最终的露白和发芽,但显著抑制油菜种子的露白和发芽进程;在油菜发芽过程中添加HYS菌液也会抑制油菜种子的露白进程,同时还抑制油菜种子的发芽和芽苗生长,而LB抑制油菜根的生长。油菜在发芽过程中,头1~2 d感染HYS菌株则显著抑制油菜种子的发芽,且感染时间越早其抑制效果越强,连续感染HYS菌株对油菜种子发芽和芽苗生长的抑制作用更强,且这种抑制作用主要在发芽的头1~3 d发挥作用。将HYS菌液离心过滤除菌,用水倍比稀释LB和上清液后培养油菜种子,发现上清液经100和1 000倍稀释后促进油菜种子的发芽。上述结果表明假单胞菌HYS菌株在油菜种子发芽和早期生长过程中不适宜用其进行生物防治,但适当稀释HYS上清液可促进油菜种子发芽和生长。