Effects of ambient and elevated ~textrmCO2 and high temperature, and their interactions with zero and applied nitrogen supply (NN-no nitrogen and AN-applied nitrogen) were studied on soybean (Glycine max L.) in 2001. In this experiment, elevated ~textrmCO2 (650 ~mu~textrmmol.~textrmmol-1 ) and temperature (+5~circ ) increased total dry mass at final harvest by 125% and 119% and seed weight per plant by 57% and 105% for NN and AN plants, respectively. Although the influence of temperature and temperature x ~textrmCO2 were not significant, the influences of ~textrmCO2 concentration and temperature x ~textrmCO2 concentration were significant on total dry weight and seed weight, respectively. In particular, seed weight per plant was increased, while weight per one hundred seed weight was decreased with elevated ~textrmCO2 and temperature. The N supply increased biomass and seed weight per soybean plants. The results of this study suggest that the long-term adaptation of soybean growth at an elevated ~textrmCO2 concentration and high temperature might potentially result in a increase in dry matter production and yield.

Fifty-four Korean native and 28 foreign rice varieties harvested in 1998 and 1999 were examined for antioxidative activity that is measured to a chemiluminescence and superoxide radical intensity, by the flow injection chemiluminescence (FI-CL) system and an electron spin resonance (ESR) spectrophotometer, respectively. In the chemiluminescence measurement by FI-CL, radical scavenger activity did not differ significantly among rice varieties between origin types of rice varieties, and between storage periods. GinSun and Hongchoengdo, colored rice exhibited high electron scavenging effect by ESR. Therefore, these results indicate that the pigments of rice varieties may play important antioxidative roles and that it may be possible to breed rice varieties with higher antioxidative potentials.

To analyze their isoflavones contents by HPLC analysis during two years on 60 collected old local traditional soybean varieties from various districts of Korea was conducted. There was a yearly variation in the seed isoflavon concentrations. The total contents on 5 isoflavones were in the range from 16.21mg/g to 25.21 mg/g and from 6.47 mg/g to 15.44 mg/g, in 1997 and 1998, respectively. Collected soybean from Gunsnsi-1(25.21 mg/g) in 1997 and from Gangjingun-3 (16.50 mg/g) in 1998 showed the highest amount of isoflavones as compared with other collected soybean varieties. The highest amount among 5 isoflavones was genistin as 48.45% and 49.73%, in 1997 and 1998, respectively, indicating the genotypic variation in seed isoflavon contents of local soybean cultivar. Our data suggest that it may be feasible for improving soybean variety with higher antioxiadtive activity and substances.

Sixty local soybean cultivars were evaluated on the antioxidative activity by superoxide dismutase (SOD), 1, 1-diphenyl-2-picrylhydrazyl (DPPH), thiobarbituric acid(TBA), and chemiluminescence using the FI-CL system. Soybean were collected throughout the country, and were grown over two years (1997 and 1998) for measuring antioxidative activity in soybean seeds. There were differences in antioxidative activity depen-ding on the method of measurement and variation of the crop year. Soybeans from Kwangyang-shi-1 (76.78%) in 1997 and Kangjin-gun-3(79.14%) in 1998 showed the highest SOD activity, whereas those from Hwasoon-gun (80.43%) in 1997 and Kangjin-gun-2 (49.82 %) in 1998 exhibited the highest DPPH activity. Soybeans from Chongup-gun-2 (75.77%) in 1997 and from Yochon-shi-5 (69.17%) in 1998 exhibited the highest TBA activity, and those from Jinahn-gun (48.99%) in 1997 and Kohung-gun (49.73%) in 1998 exhibited the highest activity using the chemiluminescence method. These results suggest that it may be possible to develop soybean varieties with higher antioxidative activity

Fifty-four Korean native and 28 foreign varieties harvested in 1998 and 1999 were examined for superoxide dismutase (SOD) and peroxidase (POD) activities. The SOD and POD activities of leaves extracts in Korean native and foreign rice varieties showed variation at the heading stage. The activities of SOD and POD changed with growth stage. In comparison of storage duration, the SOD and POD activities of the extract from three months stored seeds in Korean native (CV=53.3%) and foreign rice (CV=57.9%) varieties were higher than that of stored rices for a year in seed extracts although the activities among varieties did not show significant variation. Also, the averaged activity of foreign rice varieties (SOD=12.9%) was relatively higher than that of korean native rice varieties (SOD=10.7%). The test of activity at the enzymatic level related to antioxidative activity suggests that the rice varieties with higher antioxidative potentials can be developed and also may provide information with rice breeder to breed rice variety with a high antioxidative activity

This study was to investigate antioxidative activity of rice grain using 1, 1-Diphenyl-2-picrylhydrazyl(DPPH) and thiobarbituric acid (TBA) method and germination ability for screening rice varieties with high antioxidative activities on korean native and foreign rice varieties harvested in 1998 and 1999. The average antioxidative activity of foreign rice varieties (DPPH 63.5% and TBA 55.2%) was significantly higher than that of native rice varieties (DPPH 47.2% and TBA 45.6%) on varieties harvested in 1999. The promptness index (PI) of native rice varieties was higher in stored rices for three months (mean PI=160.7) than that of stored rices for a year (mean PI=141.6). On the other hand, the PI of foreign rice varieties was higher in stored rices stored for a year (mean PI=176.7) than that of stored rices for three months (mean PI=157.5). Varieties with high redness of hulled rice (a-value) showed significant lipid peroxidation inhibitory activity to DPPH in a stored rices for a year (r=0.5744** ) and stored rices for three months (r=0.5630** ) . These results indicate that the pigments of hulled rice varieties may play important antioxidative roles and colored rice varieties with higher antioxidative potentials can be developed and also may provide information with rice breeder to breed rice variety with a high antioxidative activity for a rapid screening of a small amounts of a large number of samples using color value.

This study was conducted to assess the allelopathic potentiality of Korea traditional seventy-nine rice (Oryza sativa L.) cultivars on barnyardgrass (Echinochloa crus-galli P. Beauv. var. oryzicola Ohwi) and to identify possible allelopathic compounds from selected rice cultivars, such as Seogandodobyeo, Huadobyeo and Heugbalbyeo. In the straw mixture, Seogandodobyeo showed the greatest inhibition (67.07%) on total emergence percentage. The greatest inhibition on total seedling length and dry weight of barnyardgrass occurred in Huadobyeo (58.32 %) and Heugbalbyeo (81.20%), respectively. An HPLC analysis with nine standard compounds showed that the concentrations and compositions of allelopathic compound depend upon the cultivars. Four compounds including Ο-coumaric acid in Seogandodobyeo extracts, four compounds including p-coumaric acid in Huadobyeo extracts, and seven compounds including Ο-coumaric acid in Heugbalbyeo were detected, respectively. Ο-coumaric acid (0.97 mg/g) in Seogandodobyeo, p-coumaric acid (0.92mg/g) in Huadobyeo and Ο-coumaric acid (1.02 mg/g) in Heugbalbyeo was detected as the highest amounts, respectively. The preliminary identification by HPLC analysis resulted in peaks with retention times close to those of standards which were confirmed with EI/MS. The mass spectra of p-coumaric, and Ο-coumaric acids showed molecular ions (m/z) at 164 and 164, and their base peaks (m/z) at 164 and 118, respectively.