To study the cause of physiological disorder in leaf of ginseng cultivated at paddy soil, the degree of brown-colored symptom (BCS) and the contents of inorganic matter in leaf were investigated by irrigating the solution of ferric andferrous iron of 0.1~2.0%, and citric acid of 1.0~4.0% on bed soil, respectively. Ratio of BCS by variety was as high as85.0% in Yoenpoong, while it was as low as 5.4%, 7.5% in Chunpoong and Hwangsook, respectively. The contents ofinorganic matter of leaf in Yoenpoong were lower in P₂O5, Ca, and Mg, while it were higher in K, Fe, and Mn than othervariety. Iron solution caused BCS more distinctly when each ferric and ferrous iron were dissolved with 1.0% citric acidthan when each iron was dissolved without citric acid. Ferric iron caused BCS more effectively than ferrous iron. BCSoccurred in 4.0% citric acid was as same as 2.0% ferric iron mixed with 1.0% citric acid. Low P₂O5 and high Fe content inleaf appeared in both of artificial and natural symptoms. We concluded that excessive Fe uptake caused BCS to leaf becausethe solubility of iron was increased in condition of low soil pH.

In mammals, puberty is a process of acquiring reproductive competence, triggering by activation of hypothalamic kisspeptin (KiSS)-gonadotropin releasing hormone (GnRH) neuronal circuit. During peripubertal period, not only the external genitalia but the internal reproductive organs have to be matured in response to the hormonal signals from hypothalamic-pituitary-gonadal (H-P-G) axis. In the present study, we evaluated the maturation of male rat accessory sex organs during the peripubertal period using tissue weight measurement, histological analysis and RT-PCR assay. Male rats were sacrificed at 25, 30, 35, 40, 45, 50, and 70 postnatal days (PND). The rat accessory sex organs exhibited differential growth patterns compared to those of non-reproductive organs. The growth rate of the accessory sex organs were much higher than the those of non-reproductive organs. Also, the growth spurts occurred differentially even among the accessory sex organs; the order of prepubertal organ growth spurts is testis = epididymis > seminal vesicle = prostate. Histological study revealed that the presence of sperms in seminiferous tubules and epididymal ducts at day 50, indicating the puberty onset. The number of duct and the volume of duct in epididymis and prostate were inversely correlated during the experimental period. Our RT-PCR revealed that the levels of hypothalamic GnRH transcript were increased significantly on PND 40, suggesting the activation of hypothalamic GnRH pulse-generator before puberty onset. Studies on the peripubertal male accessory sex organs will provide useful references on the growth regulation mechanism which is differentially regulated during the period in androgen-sensitive organs. The detailed references will render easier development of endocrine disruption assay.

The development of random amplified polymorphic DNA (RAPD) and expressed sequence tag-derivedsimple sequence repeats (EST-SSRs) provided a useful tool for investigating Korean ginseng genetic diversity. In this study,18 polymorphic markers (7 RAPD and 11 EST-SSR) selected to assess the genetic diversity in 31 ginseng accessions (11Korean ginseng cultivars and 20 breeding lines). In RAPD analysis, a total of 53 unique polymorphic bands were obtainedfrom ginseng accessions and number of amplicons ranged from 4 to 11 with a mean of 7.5 bands. Pair-wise genetic similaritycoefficient (Nei) among all pairs of ginseng accessions varied from 0.01 to 0.32, with a mean of 0.11. On the basis of theresulting data, the 31 ginseng accessions were grouped into six clusters. As a result of EST-SSR analysis, 11 EST-SSR mark-ers detected polymorphisms among the 31 ginseng accessions and revealed 49 alleles with a mean of 4.45 alleles per primer.The polymorphism information content (PIC) value ranged from 0.06 to 0.31, with an average of 0.198. The 31 ginsengaccessions were classified into five groups by cluster analysis based on Nei’s genetic distances. Consequently, the results ofginseng-specific RAPD and EST-SSR markers may prove useful for the evaluation of genetic diversity and discrimination ofKorean ginseng cultivars and breeding lines.

The genetic base was defined as the ancestral pool from which crop varieties were derived, and was used to characterize genetic diversity in crop breeding. Number of primary parents used between 1913 and 2002 in Korean soybean breeding programs was 65 and

In vitro culture of panicle has been the method to accumulate starch and protein in immature grains by providing nutrients after florets crossed between remote genotypes artificially. Grain filling means embryo development and sucrose translocation from photosynthetic source, and starch manufacture in endosperm. The concentrations of sucrose used to culture immature rice panicle were 5, 10, 15, 20% and glutamine was 20 mM. When immature rice panicles at 5 days after flowering were cultured in distilled water with different concentrations of sucrose, glutamine 20 mM and MS medium with different concentrations of sucrose, glutamine 20 mM for 30 days the later was effective on grain filling. The optimal concentration of sucrose on grain filling in vitro culture of rice panicle was 10% and the weight of grain cultured was 10.14 mg that was corresponded to 57% of intact plant. In the method of treating plant growth regulators, the culture of immature rice panicle adding in MS medium with Kinetin, IAA, ~textrmGA3 were effective on grain filling than the culturing of immature rice panicle after submerging in solutions of Kinetin, IAA, ~textrmGA3 for 1day. When immature rice panicle was cultured in MS medium with sucrose 10% and Kinetin 46.47 ~mu M it was effective on grain filling, respectively. The weight of grain cultured was 13.1mg that was corresponded to 75% of intact and germination rate was 51 %. When immature rice panicles were cultured in medium with different concentrations combined with Kinetin 4.65, 46.47, 464.7 ~mu~textrmM , IAA 5.71, 57.08, 570.80 ~mu~textrmM for 30 days and in medium with IAA 5.71, 57.08, 570.80 ~mu~textrmM for 15 days after culturing in medium with Kinetin 4.65, 46.47, 464.70 ~mu~textrmM for 15 days the effect on grain filling was similar.