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

以“盐果”水稻品种及其矮化近等基因系为材料，进行了与上述项目名称有关的若干试验。结果表明：(1)不同品系对GA_3、赤霉素生物合成抑制剂、IAA及其前体的响应程度不同。Sh-d_1和Sh-d_<18>^h的茎部内源IAA提取量低于“Shiokari”。(2) Sh-d_<13>和Sh-d_6的上两个节间过氧化物酶活性显著高于“Shiokari”。其他矮系也倾向于表现出比“盐果”更高的活性。过氧化物酶活性与第二节间长度呈显著负相关。(3)测定了不同生长阶段上三节间木质素含量。抽穗期木质素含量（%）与成熟期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种任意序列的10-mer单引物，在“Shiokari”和3个矮秆近等基因系之间扩增出随机扩增的多态性dna （rapd）。在3个矮系中检测到的4个RAPD中，有1个RAPD在F_2群体中分离率为3∶1。目前正在寻找新的rapd，并对矮化基因和rapd进行连锁分析。

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.