 Method for normxia, hypoxia and anoxia treatment on germinated rice  4 Rice varieties were tested: Anoxic tolerant Var; WD-3 and PBR (weedy rice collected from Korea) Anoxic intolerant Var: Juan byeo (JA)and Nampyeonbyeo(NP) Direct seeded rice, especially water seeding, requires strong hypoxia tolerance for stable seedling establishment under submerged paddy. This study was carried out to understand relationship between anoxia tolerance and carbohydrates catabolism in anoxic rice seedlings of japonica rice. Four rice cultivars were experimented as anoxic tolerant rice cultivars (cvs WD-3, PBR) and susceptible rice cultivars (cvs Juanbyeo:JA, Nampyeongbyeo:NP). The coleoptile elongation and fresh weight were markedly supressed by anoxia than normoxia, however those of WD-3 and PBR was faster than JA and NP. Soluble sugar concentration of WD-3 and PBR (tol var.) was more increased than JA and NP (sus var.) under anoxia. Especially maltose concentration of WD-3 and PBR (tol var.) increased up to 2-fold at 3 days after treatment and was retained until 9 days after treatment however that of JA and NP increased only 1.3-fold. β-Amylase that cleaves maltose from starch, those activities of WD-3 and PBR were increased up to 10-fold at 9 days after treatment than before treatment. Otherwise α-amylase activity of WD-3 and PBR was rapidly decreased after treatment. These results suggest that β-amylase activity strongly associate with degradation of sugar from starch in endosperm during germination stage and its product as maltose support elongation of rice coleoptiles in anoxia. References Discussion Materials & Methods Objective Abstract Change of β-Amylase Activity In Germination and Early Rice seedlings Under Hypoxic and Anoxic Water Ji-Young Shon 1, Joonhwan Kim 1, Chung-Keun Lee 1, Jong-Cheol Ko 1, Bo-keong Kim 1, Woon-ho Yang 1, Won-Ha Yang 1, Chung-Kon Kim 1, Yeon-Gyu Kim 1 and Nam-Jin Chung 2 (1)Rice Research Division, National Institute of Crop Science, RDA, Suwon, South Korea (2)Department of Crop Science and Biotechnology, Chonbuk National University, Jeonju, South Korea TreatmentMediaOxygenTempLight Normoxia (Air)MoisturizedAmbient air 18±4 ℃ (phytotron) 12/12h (light/dark) Hypoxia-submergedDW7-9ppm Anoxia-submerged0.1%agar<1 ppm Background Strach degradation JiYoung Shon: 3%, Direct-seeding 97%, Machine-transplanting  Rice cultivation method of South Korea  Although direct seeding method has advantages of lavor and time saving, it was not widely distributed. Unstable seedling establishment, lodging and sprouting of weedy rice are the reason why direct-seeding method cannot widely distributed in South Korea. Machine transplanting culture for semi-adult Seedlings  To find japonica rice germplasm having hypoxic and anoxic tolerance adabtable environment of south Korea  To investigate the physio-biochemical characteristics of hypoxic and anoxic tolerance of rice germination and early seedlings  Increment of β-amylase activity may contribute to elongation of rice early seedlings at submerged anoxic condition.  Expression of BAMY1 at rice early seedling stage proved that β-amylase was synthesized de-novo.  Maltose play an important role in rice anoxic seedlings that provide energy source as well as carbon building block of cell wall and may control cell osmosis,  Shon, J Ph.D thesis. Chonbuk National University.  Zhang, H., et al Planta 220:  Yoon, B Korean J. Crop Science 33(3):  Magneshi, L., Kudahettige, R., Alpi, A. & Perata, P Plant Biology 11: Normoxic, Hypoxic, Anoxic treatment Phytotron chamber Air Hypoxia AnoxiaA B Fig 1. Coleoptile elongation behavior of 4 rice cultivars under air, hypoxia and anoxia. (A: WD-3, B: Juan) Fig 2. Soluble sugar and maltose concentration in rice seedlings of 4 cultivars that were treated with air, hypoxia and anoxia at 0, 3, 6 and 9 days atert treatment. Results Fig 4. Differential expression of transcripts of genes related with starch degradation metabolism in WD-3(WD3) and Juanbyeo(JA). The normalized data were hierachically clustered using average linkage on Euclidean distance. Fig 3. α-Amylase activity and β-Amylase activity in rice seedlings of 4 cultivars that were treated with air, hypoxia and anoxia at 0, 3, 6 and 9 days atert treatment.