【摘要】 用免疫金电镜法观察了大叶烟花柱、珠孔及助细胞内玉米素 ( t- Z)、吲哚乙酸( IAA)、赤霉素 ( GA7与 GA4 )和脱落酸〔( + ) ABA〕的分布。刚授粉时的花柱引导组织细胞内与胞间基质中 t- Z较多、IAA、GA7/4 、( + ) ABA较少 ;授粉后 2 4 h(此时花粉管已穿过花柱中部 ) ,该部位 t- Z显著减少 ,IAA略增加 ,GA7/4 显著增加 ,而 ( + ) ABA仍较少。授粉后 2 4 h,花柱中段薄壁组织细胞内与胞间基质中 IAA比刚授粉时显著增加。增加的 IAA、GA7/4 主要分布在淀粉体、液泡与胞间基质中。穿过花柱中部的花粉管壁上有 IAA。刚授粉时珠孔与助细胞内 t- Z较多 ,丝状器内有大量的 t- Z;授粉后 96h,这些部位的 t- Z显著减少。刚授粉时珠孔与助细胞内 IAA、GA7/4 、( + ) ABA较少 ;授粉后 96h,除退化助细胞与宿存助细胞内 GA7/4 较多外 ,其它部位的这些激素仍较少。根据这些结果 ,讨论了雌蕊内这 4类植物激素的分布特点和花粉管定向生长的关系更多还原

【Abstract】 Up to now,little is known about distribution and function of phytohormones in the pollen tube growth track through pistils.Distribution of trans- zeatin ( t- Z) ,indele- 3- acetic acid ( IAA) ,gib- berellins A7and A4 ( GA7/4 ) ,and( + ) abscisic acid〔( + ) ABA〕in the style,micropyle and synergids of N icotiana tabacum var.macrophylla were observed with immunogold electron microscopy.Segments from middle part of the styles and ovules at various stages at and after pollination were fixed with 2 % EDC〔1 - ethyl- 3- ( 3- dimethyl aminopropyl) carbodiimide〕and mixed paraformaldehyde and glutaralde- hyde for acidic phytohormones ( or only with the latter for t- Z) ,then stightly postfixed in 0 .5 % OSO4solution for 30 min.After dehydration,samples were embedded in Epon 81 2 resin.Following etched in 1 0 % H2 O2 for1 0 min,ultrathin sections were immunostained respectively with rabbitanti- t- Z polyclonal antibody ( PAb) ,anti- IAA methyl ester PAb,mouse anti- GA monoclonal antibody( MAb,specifically recognizes methyl esters of GA7and GA4 ) ,or anti- ( + ) ABA methyl ester MAb.Protein Acolloidal gold ( Φ1 0 nm) was used as a marker for rabbit PAbs while sheep anti- mouse lg G- colloidal gold( Φ1 0 nm) for mouse MAb.At pollination plenty of t- Z but a few IAA and GA7/4 were observed in cells and intercellu- lar matrix of the transmitting tissue.One day after pollination,when pollen tubes had penetrated the transmitting tissue,the gold granules of t- Z remarkably decreased,but those of IAA slightly increased; and those of GA7/4 obviously increased in the same region.IAA in cells and intercellular matrix of stylar parenchyma greatly increased from just at pollination to one day after pollination.Increased IAA and GA7/4 were mainly localized in amyloplasts,vacuoles and intercellular matrix.IAA appeared in the walls of pollen tubes passing the transmitting tissue.High level of t- Z in themicropyle and the synergids( par- ticularly abundant t- Z in the filifrom apparatus) greatly decreased from just atpollination to 4 days after pollination.GA7/4 were less in the synergids at pollination butincreased in both the degenerate and per- sistent synergids 4 days after pollination.GA7/4 and IAA in the micropyle or IAA in the synergids main- tained at lower levels4 days after pollination.( + ) ABA in the pollen tube growth track was rarely ob- served during the whole course.According to the results,the relationship of the distribution mode of these four phytohormones in tobacco pistil with pollen tube guidance is discussed.更多还原