Relationship between severity of blackleg (Leptosphaeria maculans/L. biglobosa species complex) and subsequent primary inoculum production on oilseed rape stubble

The relationship between severity of blackleg, or phoma stem canker ( Leptosphaeria maculans/L. biglobosa ), and subsequent primary inoculum production on oilseed rape ( Brassica napus ) stubble was investigated at two sites in France over 3 years. The quantity of primary inoculum produced in the following year increased with canker severity, from 1·9 to 10·8 pseudothecia cm⁻² on stubble with the least and most severe cankers, respectively. Stubble incubated at Le Rheu (cooler, more rain) had 1·7 times more pseudothecia than stubble incubated at Grignon. Stubble collected at Grignon had 2·7 times more pseudothecia than that collected at Le Rheu. The use of Darmor, a cultivar with a good level of quantitative resistance, reduced the severity of canker in the field, but not the subsequent inoculum production for stubble of the same canker severity class. At both sites, maturation of pseudothecia occurred after 63–75 days of incubation and increased with canker severity with a mean of 0·5 and 3% mature pseudothecia appearing per favourable day, on stubble with the least and most severe cankers, respectively. A simplified procedure for pseudothecial quantification proved satisfactory: for all three observers, most (91–96%) of the fructifications counted as pseudothecia were real pseudothecia. Only a few (4–14%) of the fructifications considered as non-pseudothecia were in fact pseudothecia of L. maculans . The total area occupied by pseudothecia, which was simpler and faster to evaluate, was correlated (coefficient of determination, R ² = 71%) with the number of counted pseudothecia. The results presented here make it possible to forecast the quantity of available primary inoculum for a given disease severity.     

Characterisation of sunflower root colonisation by <Emphasis Type="Italic">Phoma macdonaldii</Emphasis>

Phoma macdonaldii, the causal agent of black stem disease of sunflower (Helianthus annuus), also attacks roots and collars of the plants, resulting in early death. Totally resistant lines do not exist for infection of the aerial parts, but tolerant lines have been characterised. This paper presents a study on colonisation of a partially resistant and a susceptible sunflower line by P. macdonaldii. The fungus was transformed with a constitutively expressed reporter gene encoding the jellyfish green fluorescent protein via Agrobacterium tumefaciens, and colonisation of sunflower roots by this transformed strain was studied by various microscopy techniques including confocal and scanning electron microscopy. The results show that penetration of the fungus into the root occurred through natural fissures or through the epidermis and was similar in both lines. In contrast, the colonisation rate of the stele was reduced in the partially resistant line, and the morphology of the fungal hyphae was also affected. The effect on hyphal morphology was strongest in the stele, indicating a localised production of defence compounds in this line.     

Development of insect‐resistant transgenic rice with Cry1C*‐free endosperm

BACKGROUND: Yellow stem borer (Tryporyza incertulas Walker), striped stem borer (Chilo suppressalis Walker) and leaf folder (Cnaphalocrocis medinalis Guenec) are three lepidopteran pests that cause severe damage to rice in many areas of the world. In this study, novel insect‐resistant transgenic rice was developed in which Bt protein expression was nearly absent in the endosperm. The resistant gene, cry1C*, driven by the rice rbcS promoter (small subunit of ribulose‐1,5‐bisphosphate carboxylase/oxygenase), was introduced into Zhonghua 11 (Oryza sativa L. ssp. japonica) by Agrobacterium‐mediated transformation. RESULTS: A total of 83 independent transformants were obtained, 19 of which were characterised as single‐copy foreign gene insertion. After preliminary screening of the T₁ families of these 19 transformants in the field, six highly insect‐resistant homozygous lines were selected. These six homozygous transgenic lines were field tested for resistance to leaf folders and stem borers, and for their agronomic performance. The Cry1C* protein levels in leaves and endosperm were measured by ELISA. Subsequently, the elite transgenic line RJ5 was selected; this line not only possessed high resistance to leaf folders and stem borers, normal agronomic performance, but also Cry1C* expression was only 2.6 ng g^?1 in the endosperm. CONCLUSION: These results indicated that RJ5 has the potential for widespread utility in rice production. Copyright © 2009 Society of Chemical Industry     

杂交早稻亲本系生育特性的观测研究

对 7个早籼恢复系和 7个不育系分期播种的观测表明 ,在合肥地区 4月 6～ 16日播种 ,一般 6月下旬～ 7月初始穗 ;播期每推迟 5d ,播始历期缩短 2～ 4d ,主茎叶片数呈略减趋势或变化不大 ,穗粒性状无明显规律性变化。根据本地气候特点和各亲本系播始历期的长短 ,提出其春播复制的播期只宜安排在 4月 5～ 2 0日 ,抽穗扬花期在 6月 3 0日前后 ;父、母本行比 2∶10～12 ,每穴栽双株     

大花蕙兰的茎段培养

以大花蕙兰试管苗茎段为外植体,在１／２ＭＳ＋ＢＡ２ｍｇ／Ｌ＋ＮＡＡ０．１ｍｇ／Ｌ＋香蕉１００ｇ／Ｌ的培养基上可１次成苗。在添加ＢＡ０．４ｍｇ／Ｌ的ＶＷ及１／２ＭＳ培养基上可诱导产生原球茎,通过原球菌的继代增殖、诱导成苗,也可在短期内获得大量种苗。     

A New Way for Analyzing the Strength of Frame of Truck Crane

In this paper, the formulas calculating the stress of frame of truck crane are deduced according to the thin wall structure theory, the calculation program is compiled and used in calculating the stress of the truck frame. The calculated results are checked and complemented by structural analysis program with finite element SAP5, providing the theoretical and calculation basis for design and calculation of the frame.     

The Improvement Algorithm of the Hock-Brown Strength Criterion Parameters for Rockbody

Based on a lot of testing data from Xiluodu Hydropower power station and ertan hydropower staton,the parameters such as m and s of the Hoek Brown strength criterion are analyzed in this paper.It is found that m and s are a couple of variables with great corelativity.While the strength of rockbody is a constant,there is negative correlativity between m and s determined by the property and location of rockbody,it is suggested in the paper that the corelativity between m and s is very important parameter which can not be neglected.     

虎杖(Polygonum cuspidatum)茎尖愈伤组织诱导及高频植株再生

    以虎杖(Polygonum cuspidatum)茎尖为外植体进行离体再生研究,探讨苗龄、接种方式、不同植物生长调节剂、硝酸银和蔗糖等对虎杖茎尖愈伤组织诱导、不定芽分化和生根的影响.结果表明:愈伤组织诱导的最佳培养基为MS+蔗糖28 g·L-1+琼脂5.5g·L-1+2,4-D 1.5 mg·L-1+6-BA 1.0 mg·L-1,诱导率为100%;3～7 d苗龄的虎杖茎尖愈伤组织诱导能力无显著差异,诱导率均达到95%以上,此后随着苗龄的增加,愈伤组织诱导能力快速下降,苗龄为12 d时愈伤组织诱导率只有55.6%;以正插(形态学下端插入培养基)方式接种的外植体愈伤组织诱导率显著大于反插(形态学上端插入培养基)和平放;不定芽分化最佳培养基为MS+AgNO3 4.0 mg·L-1+蔗糖30 g·L-1+琼脂6.0 g·L-1+NAA 0.5 mg·L-1+TDZ0.8 mg·L-1,分化率为83.9%,增殖系数为7.63;生根培养基选用1/2 MS+蔗糖26 g·L-1+琼脂6.5 g·L-1+活性碳3%+IBA 0.2 mg·L-1+NAA 0.3 mg·L-1,生根率为89.6%.用聚氟乙烯(PVF)透气膜封口比用聚乙烯(POLY)菌膜生根率明显提高(达到100%),生根明显提前.     

猪精原干细胞体外培养条件的优化

以出生后1～5 d的长白公猪为主要研究对象,采用两步酶消化法获取睾丸细胞悬液,用Percoll不连续密度梯度法对猪精原干细胞(PSSCs)进行纯化,以碱性磷酸酶(AP)染色鉴定;利用MTT法检测2种细胞因子——胶质细胞源性神经营养因子(GDNF)和白血病抑制因子(LIF)对PSSCs发育的影响.结果表明:用Percoll不连续密度梯度法获得的PSSCs占睾丸总细胞数的(8.19±0.83)%,AP染色的阳性率为(87.47±2.90)%,表明该方法可有效获取PSSCs;MTT法检测表明,20 ng.mL-1 GDNF+1 000 U.mL-1 LIF的组合添加对PSSCs体外增殖的效果最好.     

Supportive effects of human AGM region and fetal liver stromal cells on differentiation of murine embryonic stem cells into hematopoietic stem cells and in vivo hematopoietic reconstitution

AIM: To investigate the differentiation of murine embryonic stem cells (ESCs) into hematopoietic stem cells (HSCs) by the supportive effects of human aorta-gonad-mesonephros (AGM) region and fetal liver (FL) stromal cells.METHODS: E14 ESCs were induced into embryoid body (EB) first. Then the cells from EB were further co-cultured with human AGM region and FL stromal cells in non-contact system. On day 6, the cells derived from EB were collected for Sca-1⁺c-Kit⁺ cell analysis by flow cytometry, colony forming unit (CFU) assay and teratoma formation checking. BALB/c female mice conditioned with lethal dose of γ-ray irradiation were transplanted with EB cells from different culture systems. The survival rates, engraftment of donor cells, reconstitution of hematopoietic were monitored.RESULTS: Sca-1⁺c-Kit⁺ cells in EB cells co-cultured with human AGM region and FL stromal cells had the value of (21.96±2.54)%, and the total CFU was as (520±52)/10⁵ cells, which were statistically greater than those in EB cells only cultured with human AGM region stromal cells (P＜0.05). No teratoma was found in NOD-SCID mice after subcutaneous injection of EB cells co-cultured with human AGM region and FL stromal cells. In BALB/c female mice transplanted of EB cells co-cultured with human AGM region and FL stromal cells, the survival rate was 77.8%, and the peripheral blood cell count was obviously improved on day 14. PCR results showed the recipients all had sry gene copies from donor in bone marrow. The recipient mice transplanted with EB cells only cultured with human AGM region stromal cells all died within 15 days.CONCLUSION: Stromal cells from human AGM region and FL enhance the directed differentiation of ESCs into HSCs which can reconstruct hematopoiesis in vivo.