银杉花粉生命力及其变异

中国特有植物银杉(Cathay argyrophylla)是最濒危的松杉类植物之一。研究表明,受精前胚珠的高败育率是银杉生殖效率低的重要原因之一,但迄今对银杉花粉活力及其变异仍不得而知。由于花粉活力对授粉、受精、种子产量和质量以及后代适合度都有直接影响,该研究采用TTC染色和体外萌发法测定了来自大瑶山(Dayaoshan, DYS)和花坪(Huaping, HP)两个地区7个种群16个个体52份银杉花粉样品的生活力。结果表明银杉花粉的活力水平(93.3%)与其它裸子植物相当,干燥低温条件下银杉的花粉活力比较稳定,体外萌发的适宜蔗糖浓度在13%左右。ANOVA分析揭示种群内个体间的花粉活力差异不大(p>0.05),而地区内的种群间及地区间的花粉活力有显著差异(p<0.05)。银杉花粉活力与其生殖成功没有相关性。在上述基础上,从控制授粉的角度讨论了银杉的保护策略和复壮的可能性。

POLLEN VIABILITY AND VARIATION IN CATHAYA ARGYROPHYLLA

Aims Cathaya argyrophylla is one of the most endangered conifers endemic to China.Previous studies showed that this species was characterized by unusually low fertility and high embryonic mortality,which may be factors leading to its endangerment.Because knowledge of pollen viability is important for successful reproduction of plant species,we investigated pollen viability in natural populations of C.argyrophylla.Methods We collected pollen samples from 16 individuals of seven populations in two locations,Dayaoshan(DYS)in Sichuan and Huaping(HP)in Guangxi.We evaluated pollen viability using the TTC method and analyzed its variation based on ANOVA.Important findings Pollen viability of C.argyrophylla is comparable to other gymnosperms.Viability was stable in dry and low temperature conditions,and the optional sucrose concentration for pollen germination was about 13%.We found low variation of pollen viability among individuals within populations(p>0.05)but significant differentiation between populations within regions and among regions(p<0.05).The pollen viability of C.argyrophylla is normal and thus not likely relevant to its endangerment.We proposed artificial crossings between genetically distinct populations as a potential conservation strategy for the population recovery of this endangered species.