Modes of Action of Dwarfing Genes on Physiological and Biochemical Characters in Rice (Oryza sativa L.)

以水稻品种“Shiokari”及其矮秆近等基因系为材料，进行了有关上述项目的几项试验。结果表明：(1)不同品系对赤霉素生物合成抑制剂GA_3、IAA及其前体的反应程度不同。Sh-d_1和Sh-d_&lt；18&gt；h从新梢中提取的内源IAA的量比“Shiokari”少。(2)Sh-d&lt；13&Gt；和Sh-d_6的上部两节间过氧化物酶活性显著高于Shiokari。其他矮秆品系也往往表现出比“柴井”更高的活性。过氧化物酶活性与节间长度呈负相关，特别是在第2节间。(3)测定了不同生长阶段上部3个节间的木质素含量。抽穗期测定的木质素含量(%)与成熟期测定的薄壁细胞长度呈极显著负相关。成熟期木质素含量(%)与节间长度呈正相关。(4)利用180种随机序列的10聚体随机单引物扩增技术，在“Shiokari”与3个矮秆近等基因系之间进行了随机扩增多态性DNA的扩增。在3个矮秆品系中检测到的4个RAPD中，有1个被用来研究F_2群体的分离比例，并被证实以3：1的比例分离。新的RAPD的搜索和矮化基因与RAPD的连锁分析现在正在进行AUT。

Using a rice variety "Shiokari" and its dwarf near-isogenic lines, several experiments concerning the title of project above were carried out. The results obtained are as follows : (1) Degrees of response in shoot elongation to GA_3, inhibitors of gibberellin biosynthesis, IAA and its precursors differed among lines used. Amount of endogenous IAA extracted from shoots was fewer in Sh-d_1 and Sh-d_<18>^h than in "Shiokari". (2) Peroxidase activity in the upper two internodes of Sh-d_<13> and Sh-d_6 was remarkably high as compared with "Shiokari". Other dwarf lines also tended to show higher activity than "Shiokari". A negative correlation was observed between the peroxidase activity and the internode length especially in the second internode. (3) Lignin content was measured in the upper three internodes at various stages of growth. There was significantly negative correlation between the lignin content (%) measured at heading stage and the length of parenchyma cell measured at maturity stage. On the other hand, the lignin content (%) at maturity stage correlated positively to the internode length. (4) Random amplified polymorphic DNAs (RAPDs) were detected between "Shiokari" and three dwarf near-isogenic lines by amplification using 180 kinds of single 10-mer primers of arbitrary sequence. Among four RAPDs detected in three dwarf lines, one RAPD was subjected to investigate the segregation ratio in a F_2 population and was confirmed to segregate at a 3 : 1 ratio. A search of new RAPDs and a linkage analysis of dwarfing genes and RAPDs are now carrying aut.