甘肃省白菜型冬油菜霜霉病发生规律

引起甘肃省白菜型冬油菜霜霉病的病原菌为十字花科寄生叉霜霉菌Peronospora parasitica (Pers.) Fr.该病菌可为害叶片、茎秆和角果,病部出现白色霜状霉层。据调查,2009年-2011年间,油菜收获期霜霉病发病最严重,平均发病率和病情指数达32.80%和28.40。冬油菜霜霉病田间孢子囊4月上旬始见,5月22日左右达到高峰,平均为71个/100cm2;温度、相对湿度分别为16℃、95%时,接种72h后冬油菜霜霉病即可发生;当5d内平均温度为10.3℃、平均相对湿度为61.0%和5d内降雨量累计值为1.6mm时,田间孢子囊数目达最大,为76个/100cm2。陇油9号发病率和病情指数比其它品种显著高。小麦-冬油菜轮作可减轻霜霉病的发生。     

Suppression of clubroot disease under neutral pH caused by inhibition of spore germination of Plasmodiophora brassicae in the rhizosphere

To elucidate the mechanism of clubroot suppression under neutral soil pH, a highly reproducible germination assay system under soil culture conditions was designed based on the hypothesis that germinated spores of Plasmodiophora brassicae could be identified by the absence of a nucleus (i.e. having released a zoospore to infect a root hair of the host plant). Brassica rapa var. perviridis seedlings were inoculated with a spore suspension of P. brassicae at a rate of 2·0 × 10⁶ spores g⁻¹ soil and grown in a growth chamber for 7 days. The spores were recovered from rhizosphere and non-rhizosphere soils and stained with both Fluorescent Brightener 28 (cell-wall-specific) and SYTO 82 orange fluorescent nucleic-acid stain (nucleus-specific stain). Total numbers of spores were counted under UV-excitation, and spores with a nucleus that fluoresced orange under G-excitation were counted. The significant increase in the percentage of spores without a nucleus (germinated spores) in the rhizosphere after 7 days' cultivation and the correlation with root-hair infections validated the assay system. Applications of calcium-rich compost or calcium carbonate to neutralize the soil significantly reduced the percentage of germinated spores in the rhizosphere, as well as the number of root-hair infections. The present study provides direct evidence that the inhibition of spore germination is the primary cause of disease suppression under neutral soil pH.     

芸薹属远缘杂交试管苗快繁培养基的优化

为了优化芸薹属远缘杂交试管苗的快繁培养基,探讨基因型、培养时间等因素对试管苗分化率的影响,实验对甘蓝型油菜与甘蓝以及白菜型油菜与甘蓝两种远缘杂交方式的试管苗,在10种添加了不同浓度的6-BA和NAA的培养基上进行快繁培养。采用SAS软件对培养后第20d和第30d的分化率进行分析处理,结果如下：（1）白菜型油菜与甘蓝5个杂交组合间,以及白菜型油菜与甘蓝、甘蓝型油菜与甘蓝两种杂交类型间的试管苗分化率无显著差异;除甘蓝型油菜与甘蓝杂交的试管苗在培养第30d时的分化率无显著差异外,其它情况下培养基间的诱导分化率差异均达到显著或极显著水平;（2）添加3.0 mg&;#8226;L-1 6-BA（6-苄基嘌呤）和0.2 mg&;#8226;L-1 NAA（萘乙酸）的MS培养基对试管苗的诱导分化效率显著或极显著高于其它快繁培养基;（3）不同培养基培养的试管苗在培养20d和30d时的分化率呈高度正相关,但前20d的日平均分化率显著高于20~30d的日平均分化率。     

4种除草剂对胡麻田油菜、荞麦和苦荞麦的防除效果

中国西北和华北地区油菜、荞麦和苦荞麦种植面积较大,其收获时遗落在土壤中的种子翌年出苗后变成了严重危害胡麻的杂草,已成为胡麻生产中亟待解决的突出问题。笔者对2甲·辛酰溴等4种除草剂防除胡麻田油菜、荞麦和苦荞麦开展了应用试验,结果表明：40% 2甲·辛酰溴乳油、25%辛酰溴苯腈乳油和80%溴苯腈可溶粉剂3种除草剂是防除胡麻田油菜的高效除草剂,在600、450、480 g/hm²剂量下药后45天的株防效和鲜重防效均达100%,胡麻增产率分别为83.24%、87.79%、88.13%,3种除草剂在推荐剂量下对胡麻安全,其大面积示范推广的适宜剂量分别为600、450、480 g/hm²。40% 2甲·辛酰溴乳油、25%辛酰溴苯腈乳油、80%溴苯腈可溶粉剂和24%氨氯吡啶酸水剂4种除草剂是防除胡麻田荞麦的高效除草剂,在660、450、540、180 g/hm²剂量下药后45天的株防效在90.32%~98.07%,鲜重防效在97.30%~99.27%,胡麻增产率在87.31%~92.80%,4种除草剂在推荐剂量下对胡麻安全,其大面积示范推广的适宜剂量分别为660、450、540、180 g/hm²,24%氨氯吡啶酸水剂需使用防护罩喷头进行定向喷雾。24%氨氯吡啶酸水剂是防除胡麻田苦荞麦的高效除草剂,在216 g/hm²剂量下药后45天的株防效和鲜重防效分别为91.42%和98.71%,胡麻增产率为94.24%,此种除草剂在使用防护罩喷头进行定向喷雾条件下对胡麻安全,其大面积示范推广的适宜剂量为216 g/hm²。     

Long Chain Acyl-Coenzyme A Synthetase 4 (BnLACS4) Gene from Brassica napus Enhances the Yeast Lipid Contents

Long-chain acyl-Coenzyme A (CoA) synthetases (LACSs) catalyze the formation of long-chain acyl-CoA, and play important roles in fatty acid metabolism including phospholipids, triacylglycerol (TAG) biosynthesis and fatty acid β-oxidation. Here, we report the characterization of a LACS gene from Brassica napus. It is highly homologous to Arabidopsis LACS4 and thus designated as BnLACS4. The cloned gene BnLACS4 could complement a LACS-deficient yeast strain YB525. It is mainly expressed in flowers and developing seeds where lipid biosynthesis is at high rate in Brassica napus. When transiently expressed in tobacco leaves, BnLACS4 is localized in endoplasmic reticulum (ER), the common site for eukaryotic pathway of lipid biosynthesis. Expression of BnLACS4 in the yeast strain pep4 increased its lipid content. Taken together, our results suggest that BnLACS4 may be involved in lipid biosynthesis in B. napus.     

旱寒区冬油菜苗期抗寒性与抗旱性相关性分析

为了了解冬油菜苗期抗寒性与抗旱性的相关性,为北方旱寒区抗寒、耐旱冬油菜新品种选育提供理论参考,本试验对抗寒性不同的8个白菜型冬油菜品种进行苗期抗旱胁迫研究。结果表明,冬油菜抗寒性与抗旱性显著正相关;干旱胁迫后,油菜叶绿素含量逐渐增加,组织含水量与抗旱性不存在相关性,根系活力与抗旱性存在极显著相关性。     

Identification of sources and inheritance of resistance of Chinese Brassica vegetables to white blister

There is no information in the literature about the variability of resistance of Chinese Brassica vegetables, pak choi and Chinese cabbage, to the white blister disease caused by Albugo candida (Pers.) Kuntze. A collection of 43 accessions of pak choi and 19 accessions of Chinese cabbage was screened for resistance to the Portuguese A. candida isolate Ac 506 at the cotyledon stage. Different levels of resistance were found among the germplasm tested, ranging from complete resistance to full susceptibility. Most of the accessions were highly susceptible with less than 10% of resistant seedlings, and only four accessions of pak choi, presenting more than 50% resistant seedlings, were considered as new sources or resistance to white blister. Inheritance of resistance at the cotyledon stage was studied in two crosses between the most resistant pak choi accession, BRA 117, and the highly susceptible rapid cycling Brassica rapa line CrGC 1.19. It was proposed that resistance to white blister in pak choi BRA 117 is controlled by two nuclear genes with dominant recessive epistatic gene action.     

Microspore mutagenesis of Brassica species for fatty acid modifications: a preliminary evaluation

A microspore mutagenesis protocol was developed for Brassica rapa, Brassica napus and Brassica juncea for the production of double haploid lines with novel fatty acid profiles in the seed oil. Freshly isolated Brassica microspores were first cultured with ethyl methane sulphonate (EMS) for 1.5 h. The EMS was removed and the microspores were then cultured according to the standard Brassica microspore culture protocol. This protocol was used to generate over 80 000 Brassica haploid/double haploid plants. Field evaluation of B. napus and B. juncea double haploids was conducted between 2000 and 2003. Fatty acid analysis of the B. napus double haploid lines showed that saturated fatty acid proportions ranged from 5.0% to 7.7%. For B. juncea, saturate proportions ranged from 5.4% to 9.5%. Of the 7000 B. rapa lines that were analysed, 197 lines had elevated oleic acid (>55%), 69 lines had reduced α‐linolenic acid (<8%) and 157 lines had low saturated fatty acid proportions (<5%), when compared with the parental lines.     

SSR作为锚定标记构建白菜&#215;芜菁分子遗传图谱

为了将已有的大白菜分子遗传图谱和已发表的A基因组参考图谱对应起来,本研究利用国际上发表的大白菜和甘蓝型油菜A基因组特异SSR标记作为锚定标记,重新构建了白菜×芜菁分子遗传图谱。利用双亲和F1对326个SSR标记进行了筛选,共获得86个多态性分子标记。在此基础上整合了已有的400个标记,最终构建了一张由10个连锁群组成,包含了347个标记的分子连锁图谱,图谱总长度为1008.7cM,标记间的平均图距为2.91cM。此图谱上包含了已在A基因组参考图谱上定位的56个SSR标记,分布于10个连锁群上,从而将各个连锁群与参考图谱的连锁群对应起来。每个连锁群上的标记数在25～58个之间,连锁群长度在60.6～177.0cM范围内,平均图距在1.33～4.92cM之间。该图谱为白菜重要性状的遗传定位奠定了良好基础。     

NaCl和Na2SO4胁迫对白菜型冬油菜种子萌发的影响及其耐盐性分析

以6个耐盐性不同的白菜型冬油菜种子为材料,将NaCl和Na_2SO_4按摩尔比1:1混合,设浓度为0(CK)、45、90、135、180、240 mmol·L~(-1)6个处理,测定其对种子萌发和生长参数的影响,研究不同冬油菜种子萌发时的耐盐能力,以期为耐盐冬油菜的筛选提供依据。结果表明:(1)45 mmol·L~(-1)和90 mmol·L~(-1)盐浓度对种子萌发的影响不明显;135 mmol·L~(-1)和180 mmol·L~(-1)盐浓度明显抑制了种子萌发,表现为种子发芽势、发芽率、发芽指数、活力指数、胚根长、胚芽长、鲜重和干重均随盐浓度的增大而明显降低。因此,135~180 mmol·L~(-1)盐浓度可认为是耐盐性鉴定的适宜范围。(2)不同指标对盐胁迫的敏感程度差异较大,发芽指数、活力指数、胚芽长和鲜重与盐浓度均为极显著负相关,对盐胁迫最为敏感。(3)3个耐盐冬油菜ky-1、ky-10-191和ky-NDJ的种子发芽指数、活力指数、胚芽长和鲜重的耐盐临界值显著高于原有品系平油1号、10-191和ky-NDJ。ky-1、ky-10-191、ky-NDJ的耐盐临界值分别为133.895、123.264、107.399 mmol·L~(-1),而平油1号、10-191、NDJ的耐盐临界值分别为117.394、103.947、93.834 mmol·L~(-1)。用隶属函数法综合评价,耐盐性强弱顺序依次为ky-1ky-10-191平油1号kyNDJ10-191NDJ。可见,ky-1、ky-10-191和ky-NDJ的耐盐性较平油1号、10-191和NDJ均有所提高。