Interspecific Hybridization of Brassica campestris × B.oleracea Through Ovary Culture

Using three varieties of Brassica campestris, Hauarad (708), Maoshan-3 (714) and Youbai (715),as the maternal plants and one variety of Brassica oleracea Jingfeng-1 (6012) as paternalplants, crosses were made to produce interspecific hybrids through ovary culture techniques.The ovaries from the cross between B. campestrisB.oleracea (7086012 and 7146012) werecultured and ovary culture was more effective in terms of obtained seeds when ovaries werecultured in vitro at 9 d after pollination (DAP). While for the cross of 7156012, it wasbetter when ovaries in vitro cultured at 12 DAP. Among three cross combinations, the cross of7146012 showed the best response and 43 seeds per ovary were obtained. Among the mediastudied, the ovaries from the cross of 7086012 cultured on MS media supplemented with 3.0 mgL-1 BA0.1 mg L-1 NAA showed better response, and its rate of seeds per ovary reached 44.0%.While the ovaries from the other two crosses (7146012 and 7156012) showed the best responsewhen cultured on B5 media supplemented with 3.0 mg L-1 BA + 0.2 mg L-1 NAA, and the rates of seedsper ovary reached 72.0 and 60.0%, respectively. All seeds obtained from the three crosscombinations were cultured on the MS media supplemented with 1.0 mg L-1 BA + 0.05 mg L-1 NAA,and the seeds from the cross of 7156012 showed the best germination response and thepercentage of germinations reached 66.7%. The regenerated plantlets were obtained from theseseedlings after cultured on the MS media supplemented with 0.05 mg L-1 NAA. Cytological studyshowed that these regenerated plants were all true hybrids of B.campestrisB.oleracea.

Contributions of Chinese Botanists to Plant Tissue Culture in the 20th entury

This paper looks back to the development of plant tissue culture in China in the last century. Since 1934, tissue culture studies in China has kept up with the international development in the fields. Progress has been made by Chinese in nearly every branches of tissue culture, including in vitro organogenesis, shoot tip culture, anther culture, ovary culture, endosperm culture, protoplast culture as well as mass cell culture. On the basis of reviewing the articles written by Chinese on plant tissue culture, the internationally recognized contributions are specially mentioned. The applications of plant tissue culture to agriculture and industry in China are also introduced.

Preliminary Studies on the Intergeneric Hybridization Between Brassica napus with OguCMS and Orychophragmus violaceus

In the cross between B. napus with OguCMSOrychophragmus violaceus, pre-fertilizatiocompatibility was observed. An intergeneric hybrid was successfully obtained by usinovary culture. The hybrid status was confirmed by cytology, morphology, fertilityisozyme and miosis analysis. The seed setting rate was 0.0072%. An amphidiploid of thhybrid was also produced by the use of chromosome-doubling method with 0.1% colchicinetreatment. Obtaining this hybrid and its amphidiploid has important theoretical anutilization value.

High Levels of Testosterone Inhibit Ovarian Follicle Development by Repressing the FSH Signaling Pathway

The effect of high concentrations of testosterone on ovarian follicle development was investigated. Primary follicles and granulosa cells were cultured in vitro in media supplemented with a testosterone concentration gradient. The combined effects of testosterone and follicle-stimulating hormone（FSH） on follicular growth and granulosa cell gonadotropin receptor m RNA expression were also investigated. Follicle growth in the presence of high testosterone concentrations was promoted at early stages（days 1–7）,but inhibited at later stage（days 7–14） of in vitro culture. Interestingly,testosterone-induced follicle development arrest was rescued by treatment with high concentrations of FSH（400 m IU/m L）. In addition,in cultured granulosa cells,high testosterone concentrations induced cell proliferation,and increased the m RNA expression level of FSH receptor（FSHR）,and luteinized hormone/choriogonadotropin receptor. It was concluded that high concentrations of testosterone inhibited follicle development,most likely through regulation of the FSH signaling pathway,although independently from FSHR downregulation. These findings are an important step in further understanding the pathogenesis of polycystic ovary syndrome.