野生羌活种子休眠机理及破除休眠技术研究

Studies on Seed Dormancy Mechanism and Breaking Technique of Wild Notopterygium incisum

由于植被的破坏、生境破碎化以及经济利益的驱动,高寒区野生羌活（Notopterygium incisum）和宽叶羌活（N.forbesii）野生种群受到严重破坏,而繁殖率极低则是制约人工驯化栽培的主要障碍。通过野外调查、室内和田间试验相结合的方法,研究野生羌活种子休眠特性及破除休眠的技术,结果表明：羌活种子具有胚后熟特性,休眠期8-10个月,需要胚的后发育才能解除休眠;秋季采收的羌活种子,无胚或呈原胚状态,不具备发芽能力,需要后熟,解除休眠的技术为流水冲洗,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（15~25℃/2~5℃）层积,可缩短解除休眠时间,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2-3个月的暖温和低温层积,种子萌发率提高到19.8%。

Wild Notopterygium incisum Ting ex H. T. Chang and N. forbesii Boiss. have been facing more and more serious over-exploitation under the pressure of population and economy development owing to wild resource exploitation, vegetation destruction, habitat fragmentation, and lands reclamation. The short growth phase and long growth cycle of those two species make this crisis more rigorous in plateau regions with high altitude and cold weather, and very low progenitive rate is the major obstacle to artificial domestication and cultivation. Characteristic of seed dormancy and breaking technique for rare and precious species of wild N. incisium were studied in both laboratory and fields. The results of morphological dissection, physiology and biochemical measurement of N. incisium seeds indicate the seed embryo had the property of after-ripening with the dormancy period of 8-10 month, the seed dormancy could be broken down only by embryo＇s after-ripening. The seed harvested in autumn with no-embryo or the embryo at original state had no germination capacity and after-ripening was necessary. The technology for dormancy breaking was found effective as follow.seeds flushed by flowing water could make the ABA content of seeds decreased to the level needed for seed germination; seeds treated with gibberellin （GA） or both GA and 6-benzyl adenine （BA） could accelerate the germination course and improve the germination rate. The temperature-changing stratification （ 1 5 - 25℃/2 - 5℃ ） could shorten the course of dormancy breaking temperature-warming before stratification could accelerate the growth of embryo, low temperature was the necessary condition for seedling sprouting. The seed germination rate was increased to 19.8% through 2- 3 months＇ warm-temperature and 2-3 months＇ low temperature stratification.