对麻类产品质量安全问题的思考

农产品质量安全问题受到了党和政府的极大关注。这也是应对入世挑战。提高我国农产品市场竞争力的一个重要方面。麻类产品在提高质量的同时，应加强安全生产监管，对生产中使用的农药、化肥、除草剂、重金属、化工原料、化学辅料等要严加控制；应推行市场准入制，加强对产品中有毒有害物质的检测；应完善质量保障体系，健全标准体系。打破欧盟的“技术壁垒”，建立我国的技术壁垒措施。     

Morphological and crystalline characterization of NaOH and NaOCl treated Agave americana L. fiber

This study investigates the effect of NaOH and NaOCl treatments on chemical composition, morphology and crystalline structure of Agave americana L. fibers. These fibers have been subjected to NaOCl and NaOH alkali treatments at different concentrations.The percentages of lignin and hemicellulose show a decrease with alkaline treatments which, in turn, induces a modification of both morphological and crystalline structures.Unit cell dimensions and crystallite size were more affected with NaOH treatment than NaOCl one. This may result from the mercerisation process which occurs with caustic soda treatment.The observed defibrillization on the treated fiber surface proves the dissolution of the non-cellulosic components present in the fiber cell wall by NaOH and NaOCl treatments. These morphological changes may improve the interaction between matrix and fiber in composites.     

Improvement of Direct Somatic Embryogenesis in Rice by Selecting the Optimal Developmental Stage of Explant and Applying Desiccation Treatment

Summary

By selecting the optimal developmental stage of zygotic embryos used as expiants and applying desiccation treatment, we improved direct somatic embryogenesis in rice scutellum from two cultivars, Nipponbare and Sasanishiki. Zygotic embryos isolated 14-17, 21, 28-30 and 35-40 d after anthesis (DAA) from Nipponbare and 14-17, 18-21, 28-30 and 40-42 DAA from Sasanishiki were cultured on the embryo induction medium (EIM). Then they were transferred to embryo maturation medium (EMM) and germinated on the embryo germination medium (EGM). Only immature zygotic embryo isolated 14-17 DAA from Nipponbare and Sasanishiki could develop somatic embryos that germinated. Explants from embryos at other developmental stages could develop somatic embryos only until the elongating or scutellar stage. They enlarged and formed callus without further development. The EIM and EMM consisted of N6 macronutrients, B5 micronutrients, and B5 vitamins, supplemented with 0.1 g L^-1 casein hydrolysate, 1.5 g L^-1 proline and 1 g L^-1 MES buffer. EGM consisted of MS macro- and micronutrients and MS vitamins without organic supplement. In addition, 2 mg L^-1 2,4-D was added to EIM, 1 mg L^-1 2,4-D to EMM and 0.01 mg L^-1 zeatin to EGM. Developmental processes of somatic embryos derived from the expiants were observed by scanning electron microscopy. Desiccation treatment of maturing somatic embryo was proved to produce fully mature somatic embryos capable of germinating vigorously.