党参交配系统及自花结实率低的初探

Mating system and causes of low fructification rate by self-pollination of Codonopsis pilosula

目的:为党参的栽培及常规育种提供帮助。方法:用TTC染色法和联苯胺-过氧化氢法测定各种质党参花粉活力和对应柱头的可授性;估算花粉-胚珠比、杂交指数的值;田间进行人工去雄、直接套袋传粉结实特性实验。结果:党参花粉在开花前2～3d,花药未裂时即有很高的活力,达80%,到开花前1d活力最高达95%;柱头在开花第1天具有最佳可授性,此时花粉活力下降,且柱头上的花粉大量散失,柱头活力持续到开花第3天;理论上估测党参各种质的花粉-胚珠比(P/O)达104.84～185.75,杂交指数(OCI)为4;党参去雄天然异交结实率达25.6%～42.4%,套袋自交的结实率达3.3%～6.7%,自交亲和指数达3.0～21.8。结论:结合P/O,OCI和传粉结实试验推测党参的交配系统为自交、异交综合特征并存,倾向于异交;自交亲和,雌雄蕊成熟期的不完全同步及柱头最佳可授期时柱头上自花的花粉量不足是导致党参自花结实率低的主要原因。

Objective：To study four kinds of germplasm resources of Codonopsis pilosula and provide the basal mating systems data for the breeding and cultivation of C. pilosula. Method： 0.5% TTC （2,3,5-triphenyl tetrazolium chloride） solution was used for the pollen viability test and benzidineand-H2O2 [ 1% benzidine in 60% ethanol, hydrogen peroxide （3%）, and water, 4：11：22 ] was used for estinmtion of the stigma receptivity. The mating systems were tested by out crossing index （OC1）, pollen-ovule ratio （P/O） and pollination by bagged and emasculated in the field. Result：The pollen viability of C. pilosula reached highly about 80% when the pollen staying in the anther, 2-3 days before the petals opening. The anther began scattering pollen before the day of the petals opening, the pollen viability was the highest about 95% , the pollen stick thickly aroud the stigma and quickliy lost in the next day. The stigma life-span was about 4-5 days, the optimal time for pollination was the first day of the petals opening, when the stigma was highly sticky and yellow. The value of out crossing index （ OC1 ） was 4, pollen-ovule ratio was between 104.84-185.75. The natural fructification rate of cross-pollination by emasculated-treatment was 25.6% -42.4%. The fructification rate and compatible index of serf-pollination by bagged- treatment were about 3.3% -6.7% and 3.0-21.8. Conclusion： The mating system of C. pilosula is mixed with serf- pollination and cross-pollination, prone to cross-pollination. The compatibility of self-pollination is high. The difference of maturing period of pistil and stamen and the lack of polen amount cause low fructification rate of serf-pollination.