Seed Storage Behavior of Taiwan Cow-tail Fir (Keteleeria davidiana (Franchet) Beissner var. formosana Hayata)

The storage behavior of seeds of Taiwan cow-tail fir (Keteleeria davidiana (Franchet) Beissner var. formosana Hayata) was investigated in the present study. A significant increase in the germination rate and a small but insignificant increase in seed germinability were obtained after chilling at 4℃ for 1~6 mo and incubating under alternating temperatures of 30/20℃ with 8 h of light. The mean germination times were reduced from 40 d for freshly collected mature seeds to 15~20 d after 3 mo of stratification. With stratification times longer than 4~5 mo, forced seed germination under chilling conditions, and complete seed germination could be achieved when the chilling period was extended to 11 mo. Freshly mature seeds lost 36, 70, and 98% of their viability after being dehydrated to 15.4, 10.5 and 7.0% moisture contents (on a fresh-weight basis), respectively. Seed viability was completely lost after 12-mo storage at 15, 4, and -20 ℃ with 7.0~15.4% moisture contents. Most Taiwan cow-tail fir seeds could not survive desiccation to a 10~12% moisture content, and viability was rapidly lost during subsequent hermetic storage at low and freezing temperatures. These results confirm that Taiwan cow-tail fir seeds exhibit recalcitrant seed storage behavior.

本研究探究了台湾油杉（Keteleeria davidiana (Franchet) Beissner var. formosana Hayata）种子的贮藏行为。经4℃低温层积1~6个月，并在30/20℃变温、每日8小时光照的条件下萌发后，种子发芽率显著提升，种子发芽力虽有小幅提升但未达统计学显著水平。新鲜采收的成熟种子平均发芽时长为40天，经3个月层积处理后，平均发芽时长缩短至15~20天。当层积时长超过4~5个月时，需在低温环境下进行强制萌发；若将低温处理周期延长至11个月，则可实现种子完全萌发。新鲜成熟种子经脱水至鲜重基准含水量分别为15.4%、10.5%和7.0%后，种子活力分别丧失36%、70%和98%。当含水量处于7.0%~15.4%区间时，种子在15℃、4℃及-20℃下贮藏12个月后，活力完全丧失。多数台湾油杉种子无法耐受脱水至10%~12%的含水量，且在后续低温及冷冻密闭贮藏过程中，种子活力会快速丧失。上述实验结果证实，台湾油杉种子表现出顽拗型种子贮藏特性。