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Planting density is one of the most important factors to improve repeseed yield, generally 30x104-45x 104 plants/hm² is recommended in national variety trials and farmer planting in China. However, poor weather and soil conditions will affect the emergence of rape seedlings. For a long time, rape farmers have formed the sowing habit of greatly increasing the sowing amount, for example, the sowing amount of farmers in Hubei, Hunan and Jiangxi reaches 7.5kg/hm². High seeding rate can produce more than 180x104 plants/hm². In period of emergence, if current rapeseed varieties can adapt to high seeding rate is unclear. In this study, 54 rapeseed varieties planted with 7.5 kg/hm² seeding rate which simulated farmer's seeding habit. The results showed that a large range genetic variation existed in no-effective plant density, plant pods, effective plant density and yield. Under high seeding rate, plant height, number of seeds per silique, plant weight and effective plant density were significantly correlated with yield. Compared to the low-yield type varieties, high-yield type varieties increased 67.6% in yield. Multivariate correlation analysis showed that effective plant density, seed number per silique and plant dry weight had a significant relationship with yield, effective plant density had the largest path coefficient on yield (0.6849), followed by plant dry weight, plant height, seed number per silique and seed weight. Different varieties could form different effective plant density, 70x104-120x104 plants/ hm² effective plant density ranges would produce higher seed yield. In order to adapt to the high seeding rate, we should select suitable varieties with higher seeding rate field trial. For genetic improving and variety breeding, we should focus on the same traits such as strong forming ability of effective plant density, seed and pod number, which related to early vigor, plant dry weight, seed number per silique, seed weight. [ABSTRACT FROM AUTHOR]

The mini‐outburst of black hole X‐ray binaries (BHXBs) is a re‐bright event of light curve, which is often detected in BHXBs with the low orbital period, such as XTE J1650‐500 (Porb≈7.69±0.02hr$$ {P}_{\mathrm{orb}}\approx 7.69\pm 0.02\kern0.22em \mathrm{hr} $$), GRO J0422+32 (Porb≈5.091850±0.000005hr$$ {P}_{\mathrm{orb}}\approx 5.091850\pm 0.000005\kern0.22em \mathrm{hr} $$) and Swift J1753.5‐0127 (Porb≈3.244±0.001hr$$ {P}_{\mathrm{orb}}\approx 3.244\pm 0.001\kern0.22em \mathrm{hr} $$). Because of its low X‐ray luminosity, the physics properties of mini‐outburst is still unclear. GX 339‐4 is a famous BHXBs with the orbital period Porb=16.9hr$$ {P}_{\mathrm{orb}}=16.9\kern0.22em \mathrm{hr} $$ and present many normal outburst and failed outburst over the past decades. However, the mini‐outburst is not still detected in GX 339‐4. In this work, using the Rossi X‐ray Timing Explorer (RXTE) observations, we investigated the energy spectrum properties of the GX 339‐4 outburst in 2004 and confirmed that the outburst in 2004 is a mini‐outburst. It is very interest that the mini‐outburst has been through a whole state transition from Low/Hard state to High/Soft state. We also give a comparison between the normal outburst in 2002 and the mini‐outburst in 2004. And we find that the two outburst present a similar Hardness‐Intensity diagram and spectral properties, which suggest that the normal outburst and mini‐outburst have a similar physics. We think that the mini‐outburst of GX 339‐4 in 2004 can be well explained by the disk instability model. [ABSTRACT FROM AUTHOR]

The formulas proposed by J. Dodd and J. L. Parks for calculating the hardenability of high-Cr white cast iron under continuous cooling condition was recommended. For broader application, some supplements were made to the formula. Through tests on the half-cooling time of typical castings, the compositions of ideal alloys were precisely designed using the Dodd’s formula. Hardness testing of heat-treated castings showed that the designed compositions were correct. The application of castings demonstrated excellent abrasion resistance.

To fully understand Brassica germplasm of waterlogging tolerance, 270 rapeseed materials from rapeseed industrial systems were evaluated for waterlogging tolerance based on relative survival rate (RSR) at germination stage after 12h of waterlogging. The results demonstrated rich genetic diversity of waterlogging tolerance, and the tolerance varied evidently among different types of varieties. The waterlogging tolerance of Brassica rapa was much stronger than that of Brassica napus. Varieties of rapeseed in downstream region of Yangtze River were more tolerant than those in upstream and midstream regions, and the tolerance was not significant between varieties of upstream and midstream regions. Waterlogging tolerance of spring rapeseeds was stronger than those of winter and semi - winter rapeseeds. Compared to hybrid rapeseeds, conventional rapeseeds showed better tolerance to waterlogging. Based on this study, waterlogging breeding lines could be selected according to specific environments and growth periods. [ABSTRACT FROM AUTHOR]

Correlation between gene expressions and physiologies was investigated under drought stress using 8 tolerant and susceptive rapeseed materials. The genes included 6 drought - related genes ( btg - 26, BnD22, P5CS, CaM, BADH and ADC). Results showed that the expression profiles were different among the genes between tolerant rape Q2 and susceptive materials Zs6 and S95 - 3. Among the 5 indicators, leaf wilting index (LWI) and relative electrolyte leakage (REL) varied largely among the varieties under drought. Correlation analysis showed that after 3h of drought, P5CS was significantly correlated to LWI and REL, BADH was correlated with REL. After 24h of drought, btg - 2 6 was significantly correlated with relative water content and REL. Results indicated that the above genes could be appraisal indices of drought - tolerance. [ABSTRACT FROM AUTHOR]

Waterlogging is one of the serious stresses in rapeseed cultivation in China. The present review focused on waterlogging effects on rapeseed growth, genetic diversity of waterlogging resistance, physiological and biochemical mechanisms of resistance to waterlogging. It also prospected future research on waterlogging resistance for molecular breeding, gene cloning and gene network. [ABSTRACT FROM AUTHOR]

Fatty acid composition of fungi is analysed through the gas chromatography( GC) technique. With specific activity a novel enzyme delta6-fatty acid desaturase was screened and isolated from Rhizopus stolonifer. In this study R. stolonifer was identified as a fungal species that produced plentiful gamma-linolenic acid. A 1475bp full-length cDNA, designated as RnD6D here, with high homology to fungal delta6-fatty acid desaturase genes was isolated from R. stolonifer using reverse transcription polymerase chain reaction and rapid amplification of cDNA ends methods. Sequence analysis indicated that this cDNA sequence had an open reading frame of 1380bp encoding a deduced polypeptide of 459 amino acids. Bioinformatics analysis characterized the putative RnD6D protein as a typical membrane-bound desaturase, including three conserved histidine-rich motifs, hydropathy profile and a cytochrome b5-like domain in the N-terminus. To elucidate the function of this novel putative desaturase, the coding sequence was expressed in Saccharomyces cerevisiae strain INVScl. A novel peak corresponding to gamma-linolenic acid(GLA) methyl ester standards was detected with the same retention time, which was absent in the cell transformed with empty vector. The percentage of this new GLA was 12.25% of total fatty acids. The result demonstrated that the coding produced delta6-fatty acid desaturase activity of RnD6D which led to the accumulation of gamma-linolenic acid.

The development of yellow-seeded varieties of Brassica napus for improving the oilseed quality characteristics of lower fiber content and higher protein and oil content has been a major focus of breeding researches worldwide in recent years. With the black-seeded 'Youyan 2' as male and the yellow-seeded GH06 as female parents respectively, F2 population of 132 individuals were obtained. A linkage map was constructed with 164 markers including 125 AFLP, 37 SSR, 1 RAPD and 1 SCAR markers distributed over 19 linkage groups covering approximately 2 549.8 cM with an average spacing of 15.55 cM. Two loci located on the 5th and 19th group were detected for the trait of seed coat color based on the linkage group using multiple interval mapping method and explained 46% and 30.9% of the phenotypic variation, respectively.