巴基斯坦高校创业教育探究--一项教师视角的案例研究

作为一个发展中国家,巴基斯坦面临着贫穷、失业等诸多问题,关注高校创业教育并给予实践,鼓励和引导创业,将极大地促进就业率,为发展巴基斯坦国家经济做出巨大贡献。此研究以巴基斯坦两所高校的教师为研究对象,希望通过对巴基斯坦的旁遮普大学和白沙瓦大学的创业教育调研来进一步认识巴基斯坦高校创业教育的现状。目前巴基斯坦高校创业教育存在着诸如体制不均衡、课程改革滞后等问题,提升巴基斯坦创业教育水平需要政府和高校的共同努力。

Detection of Tocopherol in Oilseed Rape (Brassica napus L.) Using Gas Chromatography with Flame Ionization Detector

The variation among Chinese genotypes of Brassica napus L. for seed tocopherols content and their analysis using gas chromatography has not been comprehensively reported till to date. In the present study, the tocopherol contents of four Chinese genotypes of Brassica napus L., namely, Gaoyou 605, Zhejiang 619, Zheshuang 758, and Zheshuang 72, were evaluated using three modified sample preparation protocols （P1, P2, and P3） for tocopherol extraction. These methods were distinguished as follows. Protocol one （P1） included the evaporation of solvent after extraction without silylation. Protocol two （P2） followed the direct supernatant collection after overnight extraction without drying and silylation. Protocol three （P3） included trimethylsilylation with N,O-bis（trimethylsilyl） trifluoroacetamide. Genotypic comparison of tocopherol and its isoforms revealed that Gaoyou 605 was dominant over the other genotypes with （140.5＋ 10.5）, （316.2＋ 9.2）, and （559.1＋ 24.3） ~tg g-~ of seed meal ct-, 7-, and total （T-） tocopherol, respectively, and a 0.44＋0.04 ^- to 7-tocopherol ratio. The comparison of the sample preparation protocols, on the other hand, suggests that P3 is the most suitable method for the tocopherol extraction from Brassica oilseeds and for the analysis of tocopherols using gas chromatography flame ionization detector （GC-FID）. Trimethylsilylation is the key step differentiating P3 from P1 and P2. Variations detected in tocopherol contents among the Chinese rapeseed （B. napus） genotypes signify the need to quantify a wide range of rapeseed germplasm for seed tocopherol dynamics in short and crop improvement in long.

Alleviation of arsenic toxicity by phosphate is associated with its regulation of detoxification,defense,and transport gene expression in barley

Arsenic(As) contamination in soils has posed a severe threat to safe crop production. The previous studies showed the antagonism between phosphorus(P) and As in plant growth and As uptake, while the mechanisms of alleviating As toxicity by P is not completely clear. Due to the limiting P condition, it is imperative to understand how low P addition can be used to suppress arsenate As(V) uptake and the subsequent mechanisms involved. Thus in this study we investigated the effect of P addition on As uptake, anti-oxidative enzyme activity, and anti-oxidant content, and the relative expression of transport, defense, and detoxification genes using two barley genotypes differing in As toxicity tolerance. P addition significantly reduced As concentration in plant tissues, and caused the great changes in activities of catalase and superoxide dismutase, glutathione content, and the relative expression of examined genes when the plants of the two barley genotypes were exposed to 100 μmol L^(–1) As, with ZDB160(As-tolerant) being much more affected than ZDB475(As-sensitive). The current results show that P addition can alleviate As toxicity by regulating the expression of As transport, defense, and detoxification genes to a greater extent in As tolerance of barley, suggesting the possibility of controlling As uptake and toxicity by applying low amount of P fertilizers in the As-contaminated soils.

Whole-Genome Resequencing of a Worldwide Collection of Rapeseed Accessions Reveals the Genetic Basis of Ecotype Divergence

Rapeseed (Brassica napus),an important oilseed crop,has adapted to diverse climate zones and latitudes by forming three main ecotype groups,namely winter,semiwinter,and spring types. However,genetic variations underlying the divergence of these ecotypes are largely unknown. Here,we report the global pattern of genetic polymorphisms in rapeseed determined by resequencing a worldwide collection of 991 germplasm accessions.A total of 5.56 and 5.53 million singlenucleotide polymorphisms (SNPs)as Well as 1.86 and 1.92 million InDels were identified by mapping reads to the reference genomes of "Darmor-bzh"and "Tapidor,"respectively.We generated a map of allelic drift paths that shows splits and mixtures of the main populations,and revealed an asymmetric evolution of the two subgenomes of B.napus by calculating the genetic diversity and linkage disequilibrium parameters.Selective-sweep analysis revealed genetic changes in genes orthologous to those regulating various aspects of plant development and response to stresses.A genome-wide association study identified SNPs in the promoter regions of FLOWERING LOCUS T and FLOWERING LOCUS C orthologs that corresponded to the different rapeseed ecotype groups. Our study provides important insights into the genomic footprints of rapeseed evolution and flowering-time divergence among three ecotype groups,and will facilitate screening of molecular markers for accelerating rapeseed breeding.

Role of jasmonic acid in improving tolerance of rapeseed(Brassica napus L.) to Cd toxicity

The well-known detrimental effects of cadmium （Cd） on plants are chloroplast destruction, photosynthetic pigment inhibition, imbalance of essential plant nutrients, and membrane damage. Jasmonic acid （JA） is an alleviator against different stresses such as salinity and drought. However, the functional attributes of JA in plants such as the interactive effects of JA application and Cd on rapeseed in response to heavy metal stress remain unclear. JA at 50 pmol/L was observed in literature to have senescence effects in plants. In the present study, 25 pmol/L JA is ob- served to be a ＂stress ameliorating molecule＂ by improving the tolerance of rapeseed plants to Cd toxicity. JA reduces the Cd uptake in the leaves, thereby reducing membrane damage and malondialdehyde content and increasing the essential nutrient uptake. Furthermore, JA shields the chloroplast against the damaging effects of Cd, thereby in- creasing gas exchange and photosynthetic pigments. Moreover, JA modulates the antioxidant enzyme activity to strengthen the internal defense system. Our results demonstrate the function of JA in alleviating Cd toxicity and its underlying mechanism. Moreover, JA attenuates the damage of Cd to plants. This study enriches our knowledge regarding the use of and protection provided by JA in Cd stress.

Response of seed tocopherols in oilseed rape to nitrogen fertilizer sources and application rates

Tocopherols （Tocs） are vital scavengers of reactive oxygen species （ROS） and important seed oil quality indicators. Nitrogen （N） is one of the most important fertilizers in promoting biomass and grain yield in crop production. However, the effect of different sources and application rates of N on seed Toc contents in oilseed rape is poorly understood. In this study, pot trials were conducted to evaluate the effect of two sources of N fertilizer （urea and ammonium nitrate）. Each source was applied to five oilseed rape genotypes （Zheshuang 72, Jiu-Er-1358, Zheshuang 758, Shiralee, and Pakola） at three different application rates （0.41 g/pot （N1）, 0.81 g/pot （N2）, and 1.20 g/pot （N3））. Results indicated that urea increased α-, y-, and total Toc （T-Toc） more than did ammonium nitrate. N3 was proven as the most efficient application rate, which yielded high contents of y-Toc and T-Toc. Highly significant correlations were observed between Toc isomers, T-Toc, and α-/y-Toc ratio. These results clearly demonstrate that N sources and application rates significantly affect seed Toc contents in oilseed rape.