东北红豆杉种子休眠机理与解除技术探讨

采用酶联免疫吸附分析法测定了东北红豆杉种子内源激素 (赤霉素、脱落酸、玉米素、吲哚乙酸 )含量 ,并结合形态解剖、变温层积、种子吸水性和种皮透气性等试验 ,探讨了东北红豆杉种子的休眠机理及解除休眠的技术 .秋季采收的东北红豆杉种子 ,虽然种胚结构完整 ,但体积小 ,不具备萌发能力 ,需要后熟 .风干种子形成大量脱落酸(ABA) ,种皮角质化、坚硬 ,阻碍了水气交换 ,幼小种胚被迫进入深度休眠状态 .解除休眠的技术是 ,机械磨损种皮 ,可通气、透水和减少萌发障碍 .流水冲洗 1周 ,将种子内的ABA含量降低到可以萌发的程度 .用赤霉素或赤霉素与细胞分裂素混合处理种子 ,可提前萌发 ,提高发芽率 .变温 (15～ 2 0℃ 3～ 5℃ )层积 ,可缩短种子休眠时间 ,层积前期暖温可加速胚的发育 ,低温是萌发成苗的必要条件 .经过 4～ 6个月暖温和 3～ 4个月低温层积 ,种子萌发

Dormancy mechanism and relieving techniques of seeds of Taxus cuspidata Sieb.et Zucc.

Dormancy mechanism of seeds of Taxus cuspidata and the techniques of relievi ng dormancy were studied through examining endogenous GA 3, ABA, ZR and IAA con tent in seeds by enzyme-linked immunosorbent assays (ELISA), together with othe r experiments such as morph-dissecting, stratifying seeds under different temper a tures, seed water-absorbing and air permeability of seed coats. The results sho w that the embryo of the seed collected in autumn is very small, without germinat ion ability and need post-maturation, although it has a complete structure. The r e is much ABA in air-dried seeds, and the seed coats cornify, preventing the wa t er and gas from exchanging, and resulting in the passive dormancy of the young e mbryos. The dormancy-relieving technique could be: wearing away the seed coat m e chanically, which could promote the exchange of gas and water, and reduce the ob stacles for germination; flushing seeds for one week to reduce ABA content in se eds; treating seeds with GA 3 or the mixture of GA 3 and 6--BA to change the equ ilibrium of hormones; stratifying seeds at different temperatures (15～20℃ for 4～6 months/3～5℃ for 3～4 months), which could shorten the dormancy period of seeds; warming during stratification prophase, which could facilitate the develo pment of the embryos. And low temperature is necessary for seeds' germination.