日本水稻育种目标

日本水稻育种以农业.食品产业技术综合研究机构的六个农业研究中心为主。育种目标主要是培育具有优良食味、品质及抗病性强、产量高的主食用品种,同时进行糯稻、酒米稻、饲用稻及适于直播的品种的选育。并重视低直链淀粉含量、低蛋白质含量、富含-γ氨基丁酸(GABA)以及特殊用途米的品种选育。     

Differential gene expression of the α-chain of mitochondrial H+-transporting ATP synthase between dormant and non-dormant seeds of paddy Echinochloa weeds

Gene expression was compared under favorable germination conditions between dormant and non-dormant seeds of rice paddy Echinochloa weeds and a domesticated Echinochloa species lacking dormancy. Two dormancy-specific cDNAs, Ecd1 and Ecd2 , were identified by differential display. Northern blot analysis revealed that these genes were more strongly expressed in dormant seeds than in non-dormant seeds. A database search for the Ecd1 sequence revealed no significant homology with any known proteins, but the Ecd2 sequence was highly homologous with the α-chain of mitochondrial H⁺-transporting adenosine triphosphate (ATP) synthase in rice ( Oryza sativa L.). These findings indicate that the gene encoding the enzyme associated with conventional aerobic respiration is more abundantly transcribed in dormant seeds. The results reported in the present study suggest that dormant seeds of paddy Echinochloa weeds, which appear during the period when paddy soil becomes aerobic by drainage, may maintain viability primarily by efficient conventional aerobic respiration, including ATP synthesis catalyzed by the mitochondrial H⁺-transporting ATP synthase.     

GROWTH STIMULATION OF FOREST TREE SEEDLINGS BY THE ACTIVITY OF FREE-LIVING MYCORRHIZAL MYCELIA

Observations by the late Dr. M. C. Rayner on a field experimentand the results of subsequent pot-culture experiments demonstratethat the soil activity of mycorrhizal fungi can improve thedevelopment of forest tree seedlings (Picea, Pinus, Betula)before actual mycorrhizal infection takes place. Further experimentsshow that ectotrophic mycelia are capable of stimulating endotrophictree species (Fraxinus excelsior, Cbam?cyparis lawsoniana, Robiniapseudacacia), i.e. that these ectotrophic mycorrhiza-formersbring about growth stimulation of the plant although no infectionis formed at a later stage. It is suggested provisionally thatat least some ectotrophic mycelia, Boletus scaber and Rbizopogonluteolus, may influence seedling growth by attacking soil organicmatter and liberating ‘nutrients’ from which thehigher plant benefits.     

从分类和地理差异看亚洲栽培稻的耐盐性

在水稻发芽期,筛选耐盐性品种的最适NaCl浓度是1.5%。在这个浓度下,调查了九个亚洲国家的306个品种的耐盐性。参照程氏形态分类法的稃毛标准将参试品种分成籼和粳,籼稻品种比粳稻更耐盐。酯酶(Est)同工酶分析也印证了这一结果。酯酶同工酶的等位基因Est-22、Est-3     

OCCURRENCE OF ECTOTROPHIC AND ENDOTROPHIC MYCORRHIZAS IN FOREST TREES

A short paper noting on the uncertainty of the relationshipbetween taxonomic position and the form of mycorrhiza and recordinga recent case of double infection in Lawson cypress (Cbamaecyparislawsoniana Parl.) in the south of England.