铁皮石斛2n花粉诱导及其形成的细胞机制研究

Study on 2n Pollen Induction and Cytological Mechanism of 2n Pollen Formation in Dendrobium officinale

以铁皮石斛花蕾为材料,研究不同秋水仙素处理对2n花粉诱导的影响,并探讨2n花粉形成的细胞机制。结果表明:用0.1%秋水仙素微量注射长5.53mm、宽2.3mm左右的花蕾,每天注射1次,共注射3次,诱导2n花粉效果最好,2n花粉诱导率达6.22%,2n花粉粒直径比n花粉粒直径增大49%。减数分裂中期Ⅱ发现纺锤体定位异常,表现为平行纺锤体、三级纺锤体,四分体时期观察到三分体和二分体,故纺锤体定位异常可能是铁皮石斛2n配子形成的细胞学机制之一,其2n花粉在遗传上等同于FDR型。

Effects of the various colchicine treatments on2n pollen induction inDendrobium officinalewere carried out in the current work.Cytological mechanism of2n pollen formation were also studied.The results showed that the optimum method for2n pollen induction was injecting0.1%colchicines into the flower buds at about5.53mm long and2.3mm wide for3times,once a day,with the highest induction rate up to6.22%.the diameter of2n pollen was49%larger than n pollen.The abnormal phenomena like parallel spindles and tripolar spindles at meiotic metaphaseⅡ,triads and dyads at the tetrad period were observed,so the abnormalities in spindle positioning may be one of the cytological mechanism of2n pollen formation inDen.officinale,and its2n pollens were genetically equivalent to FDR(first division restitution)type.