STUDY ON ACTION MECHANISM OF BRASSINOSTEROIDS

1）在细胞培养物和完整植物组织中均发现油菜素的生物合成途径（茶甾酮->酪甾醇-> cstasterone ->油菜素）。3-2）免疫细胞化学检测到油菜素甾体分布在多年生黑麦草花粉的淀粉体中; 3）从百合花粉中鉴定出一种茶甾酮的肉豆蔻酸酯; 4）蓝光照射水稻叶片可使水稻叶片展开，提高水稻叶片中油菜素甾体的生物活性。从麦类真菌Drechslera avenae中分离得到一种抗油菜素内酯化合物KM-01，并对其化学结构进行了测定;合成了一种具有缓释作用的合成油菜素内酯，并筛选出一种具有农业实用价值的候选化合物; 7）分析了油菜素内酯对独脚金和列当种子萌发的调节作用; 8）与生长素相比，油菜素甾醇类化合物的生长效应与微管行为和茎组织内层有关。9）油菜素甾醇类化合物的抗寒效应是基于其对植物膜的稳定作用。

1)A biosynthetic pathway of brassinolide (teasterone -> typhasterol -> cstasterone -> brassinolide) is found in both cell cultures and intact plant tissue. 3-Dehydrotesterone was found as an intermediate between teasterone and typhasterol2)In pollen of Lolium perenne, brassinosteroid is distributed in amyloplast as examined by immunocytochemistry.3)A myristate ester of teasterone was identified from lily pollen.4)Biological activity of brassinosteroids in rice leaf was increased by irradiation of blue light which causes unrolling of the rice leaf. However, this is not due to increased level of endogenous brassinosteroids.An antibrassinolide termed KM-01 was isolated from a fungus Drechslera avenae and the chemical structure was determined.Slow-releasing synthetic brassinolides were synthesized and a candidate was seltected for practical agricultural use.7)Conditioning effects of brassinolide on seed germination of Striga and Orobanche were analyzed.8)In contrast to auxin, growth effect of brassinosteroids is related with microtuble behavior and with inner layr of stem tissue.9)Cold tolerance effects of brassinosteroids are based on their stabilizing effects of plant membrane.