针对凤丹种子休眠时间长，萌发困难的现象，比较分析了凤丹种子在萌发生根的4个阶段（吸胀前、吸胀完全、露白、主根伸长）的种皮及去皮组织（胚和胚乳）中内源激素GA3（赤霉素）、ABA（脱落酸）和IBA（吲哚丁酸）的变化情况.种子萌发生根过程中，几种内源激素含量在种皮和去皮组织中的变化趋势基本相似：GA3的含量逐渐升高，ABA的含量逐渐降低，二者表现出一种拮抗关系.吸胀完全阶段与吸胀前相比，种皮中GA3的含量显著增加了12%，去皮组织中ABA含量显著下降了5.6%，表明在种子萌发初期吸胀过程中种皮的GA3含量升高以及去皮组织中ABA含量的下降对打破下胚轴的休眠起到关键作用. IBA在牡丹种子中天然存在，其含量在吸胀前、吸胀后和露白阶段变化不明显，但在主根伸长阶段迅速升高，表明IBA在根系伸长过程中具有重要作用.初步探讨了凤丹种子萌发生根过程与内源激素含量变化之间的关系，为提高种子萌发率和出苗率提供了一定的研究基础，并首次报道了牡丹种子中存在IBA .%Long-dormancy and lower germination rate are the common phenomenons in the seed of Paeonia ostii. We compared and analyzed the changes of Gibberellins A3(GA3),Abscisic acid(ABA)and indole-3-butyric acid(IBA)in the seed coat and the peeled organization(embryo and endosperm)during the four stages in the seed germination of Paeonia ostii,the before imbibition,the complete imbibition,the initial appearance of radicle and the elongation of radicle. The contents of three endogenous hormones in the seed coat had a similar change with those in the peeled organization. The content of GA3 increased gradually,while ABA decreased. At the stage of complete imbibition,the content of GA3 in the seed coat increased by 12% and ABA decreased by 5.6% in the peeled organization,than those at the before imbibition stage. It showed that the increasing of GA3 in the seed coat and the decreasing of ABA in the peeled organization,made an important role on breaking the dormancy of hypocotyl in the period of initial germination. Interestingly,endo-IBA was discovered in tree peony seeds. It was stabilization in the course of imbibitions and initial appearance of radicle;however it rose abruptly in the radicle elongation. It revealed that IBA played an important role in radicle elongating. We preliminarily discussed the variation of the endogenous hormone during seed germination process,and the study made a foundation for enhancing germination rate and it was the first report that IBA occurred in the seeds of tree peony.
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