ULTRASTRUCTURE OF THE ABDOMINAL PLEXUS OF RATS DURING HERBICIDE INTOXICATION AND TREATMENT

As a result of the study, it was found that poisoning of rats with the herbicide 2,4 - DA for 4 weeks causes a decrease in the number of neurocytes in the celiac plexus, changes the protein synthesizing and energy systems of the cell, and accumulates residual structures in the form of lipofuscin. In the neuroplasm, the number of neurofilaments and neurotubules decreases, the organization of the myelin layer of fibers is disrupted. Changes affect the structure of the intima and media of blood vessels, leading to a violation of their transport function. When rats are treated with Taktivin, they show positive dynamics in the structure of the celiac plexus; the protein-synthesizing system is restored in the nuclei and neuroplasm of a number of cells. In the connective tissue stroma, the ultrastructure of collagen fibers improves, and the number of blood vessels increases.</jats:p

Involvement of Plant Hormones and Plant Growth Regulators on in vitro Somatic Embryogenesis

In spite of the importance attained by somatic embryogenesis and of the many studies that have been conducted on this developmental process, there are still many aspects that are not fully understood. Among those features, the involvement of plant hormones and plant growth regulators on deTermining the conversion of somatic onto embryogenic tissues, and on allowing progression and maturation of somatic embryos, are far away from being completely comprehended. Part of these difficulties relies on the frequent appearance of contradictory results when studying the effect of a particular stimulus over a specific stage in somatic embryogenesis. Recent progress achieved on understanding the interaction between exogenously added plant growth regulators over the concentration of endogenous hormones, together with the involvement of sensitivity of the tissues to particular hormone groups, might help clarifying the occurrence of divergent patterns in somatic embryogenesis, and in tissue culture in general. The aspects described above, emphasizing on the effect of the concentration of plant hormones and of the addition of plant growth regulators during the different phases of somatic embryogenesis, will be reviewed in this paper. Citations will be limited to review articles as much as possible and to individual articles only in those cases in which very specific or recent information is presented.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Agroalimentarias::Centro para Investigaciones en Granos y Semillas (CIGRAS