This study was carried out to isolate and characterize the flavonoids present in corn silks. Maysin content in the unpollinated corn silks (Kwangpyeongok) showed its highest level at 3 days after silking, and decreased thereafter, while the content of open pollinated silks were consistently decreased after silking. This result indicates that the maysin content is considerably affected by the pollination of corn silk. Unpollinated corn silks were collected with excising, and ethanol employed to extract flavonoids at common temperature for 9 days. After extraction, chlorophyll, lipids etc. were removed with methylene chloride, then submitted to flash column cartridge (150 × 40 mm i.d.) packed with a preparative RP-C 18 bulk packing material (125 Å, 55-105 μm), and monitored at 352 nm. Four fractions, fraction-I, -II, -III, and -IV, were isolated from ethanolic extract of corn silks. Absorption spectrum of fraction I showed its maximum intensity (λmax) at 327 nm and 239 nm, fraction-II showed its maximum intensity at 339 nm and 274 nm, fraction-III showed its maximum intensity at 345 nm and 277 nm, and fraction-IV showed its maximum intensity at 352 nm, 270 nm, 257 nm, respectively. On the baisis of ESI micro-TOF analysis, fraction-I was identified as chlorogenic acid (m/z 355, 3-(3,4-dihydroxycinnamoyl)quinic acid, C16H18O9), fraction-II identified as a mixture of chlorogenic acid and luteolin 3'-methyl ether 7-glucuronosyl-(1→2)-glucuronide (m/z 653, C 28 H 28 O 18 ), fraction-III identified as a mixture of chlorogenic acid luteolin 7-O-neohesperidoside (m/z 595, C 27 H 30 O 15 ), and luteolin 3'-methyl ether 7-glucuronosyl-(1→2)-glucuronide, and fraction-IV identified as maysin (m/z 577, 2''-O-α-L-rhamnosyl-6-C-(6-deoxy-xylohexose-4-ulosyl)luteolin, C 27 H 28 O 14 ), respectively. From the ethanolic extract of corn silks, fraction-I was obtained about 35 mg/100 g F.W., fraction-II was about 48 mg/100 g F.W., fraction-III was about 46 mg/100 g F.W., and fraction-IV was about 138 mg/100 g F.W., respectively.

The study was carried out to analyze the relationship between analysis of antioxidant activity and the level of functional components according to particle size of corn silk. Particle size was classified into 5 groups. By particle size distribution and color difference, the total phenol content and DPPH radical scavenging activity were observed. The particle sizes of corn silk were 199.17 ㎛, 178.27 ㎛, 85.48 ㎛, 27.4 ㎛ and 20.97 ㎛, respectively. The lightness of colored pigments was increased when the particle size was decreased. The contents of free sugar (fructose, glucose, galactose, sucrose, and maltose) of corn silk were analyzed using a HPLC. The total phenol contents by the particle sizes of corn silk were 2.01 mg/g, 2.02 mg/g, 2.06 mg/g, 2.26 mg/g and 2.26 mg/g, respectively. DPPH radical scavenging activities of samples were 21.00%, 21.75%, 22.90%, 24.35% and 23.67%, respectively. Antioxidative activities of Trolox and Fe(II) in corn silk were measured by ferric reducing antioxidant power (FRAP) assay and Trolox equivalent antioxidant capacity (TEAC) assay. TEAC values of samples were 2.36 μmol TE / g dw, 2.81 μmol TE / g dw, 3.20 μmol TE / g dw, 3.36 μmol TE / g dw, and 3.44 μmol TE / g dw, respectively. FRAP values of samples were 11.67 μmol Fe(II) / g dw, 12.80 μmol Fe(II) / g dw, 13.43 μmol Fe(II) / g dw, 13.85 μmol Fe(II) / g dw and 15.95 μ mol Fe(II) / g dw, respectively. Total phenolic content and antioxidantive activities based on FRAP assay and TEAC assay were increased with decreasing particle size. In addition, DPPH radical scavenging activity was also increased. A significant correlation was also noted between DPPH radical scavenging activities and the content of phenolic compounds.

It needs to develop high phosphate-available rice that is able to minimize environmental pollution caused by phosphate fertilizer. Then we have transformed 4 rice transporter genes, OsPT(Oryza sativa Phosphate Transporter)1, OsPT4, OsPT7 or OsPT8, to rice (Oryza sativa cv. Dongjin) via Agrobacterium-mediated transformation. We tested adaptation in the P-deficient condition of Dongjin (parental) and each transgenic line in the pot and the field conditions. Definite physiological changes have been observed in OsPTs transgenic lines including culm length, root formation and heading date. Phosphate uptake at harvesting stage was about three times higher in OsPT1-OX (overexpression) and OsPT4-OX than in Dongjin (wt) without P application. There are no variations in total phosphate-content of brown rice of OsPT1-OX in spite of high phosphate uptake. Practically the expression of OsPT1 has contributed to stabilize grain production without P fertilization in rice cultivation than Dongjin.

This experiment was carried out to report some data such as survival rate, tetraploid production efficiency, and agronomic characteristics of offspring from the induced tetraploid by the colchicine treatment in rye. The colchicine was soaked with 0.05%, 12 hours in dark condition and at two growth stages (green seed and 2nd leaf stage) in diploid ryes. Flow cytometry (FC) was proved to be efficient and rapid tool for screening ploidy levels in rye, showing around 40 to 60 in DNA amount (DAP1) corresponding to diploid and 80 to 110 tetraploid. There were 18.5% of survival rate at green seed treatment and 78% at 2nd leaf stage in average of two rye cultivars, Gogu and Jogreen, but in reverse 50.9% and 1.1% in the ratio of tetraploid to total tillers among the plants survived, respectively, resulting in 9.42% of tetraploid production rate in green seed treatment and 0.86% at 2nd leaf stage, respectively. In green seed treatment, there were 33% of survival rate in Gogu, 4% in Jogreen in 1st year, but 56% in Gogu, 21% in Jogreen and 49% in Charmgreen, respectively. The rate of tetraploid to total spikes among survived was 53.7% in Gogu, 32.4% in Jogreen, and 50.9% in average in 1st year, and 64.1% in Gogu, 51.5% in Jogreen, 60% in Charmgreen, and 60.5% in average in 2nd year. In green seed treatment, tetraploid production rate (survival rate × tetraploid ratio × 100) was 17.7% in Gogu and 1.3% in Jogreen and 9.42% in average in 1st year, and 35.9% in Gogu, 10.8% in Jogreen, 29.4% in Charmgreen, and 25.4% in average of three diploid rye cultivars. By the colchicine treatment with 0.05% for 12 hours in Gogu and Jogreen, 35 tetraploid plants were obtained and they produced 2,673 seeds with 148 spikes. There were 3.3-4.4 in the number of spikes per plant, 15.6-18.3 in grain number per spike, and 37.6 g in Gogu and 46.8 g in Jogreen in the 1,000-grain weight.