【摘要】 为了探讨亚热带树木休眠理论以及休眠与树木分布的相互关系 ,研究了不同种源白花泡桐种子的休眠生理生态学特性。结果表明 :白花泡桐种子适宜发芽温度范围在 2 0～ 30℃ ,经过低温处理后 ,适宜发芽温度范围扩大到 15～ 30℃ ,具有浅低温休眠特性 ;5℃的低温处理不仅提高了不同种源白花泡桐种子的发芽率和发芽势 ,而且加快了发芽速度 ,尤其在 15℃发芽温度条件下的促进效果更加明显 ;4 0 d的 5℃低温处理效果最好 ,2 0 d、6 0 d的低温处理效果相对较差 ;没有用低温处理的不同种源白花泡桐种子 ,除了在 2 5℃发芽温度下的发芽势差异不显著外 ,在不同发芽温度条件下的发芽率与发芽势都存在着显著差异 ,但在2 0℃、2 5℃发芽温度下的平均发芽时间差异不显著。在 15℃发芽温度条件下 ,除了桂林种源以外 ,没有用低温处理的白花泡桐种子的发芽率与发芽势都随着种源纬度的增加而增加 ,而在 2 0～ 30℃的适宜发芽温度范围内随种源纬度的变化趋势不明显 ;不同种源白花泡桐种子对低温处理反应差异明显。低温处理后的中亚热带以南的低纬度种源白花泡桐种子发芽率、发芽势都较北亚热带的高纬度种源高。低温处理后的中亚热带株州种源和北亚热带南部的宜昌种源白花泡桐种子的平均发芽时间最长 ,而随着纬度的降低或增加?更多还原

【Abstract】 Eco-physiological characteristics of seed dormancy in Paulownia fortunei from six provenances were observed in order to discuss the theory of tree dormancy and the relation between dormancy and tree distribution. The six provenances were as follows: Nanning (E108°18′ N22°52), Guilin (E110°37′ N25°19′), Zhuzhou (E113°03′ N27°40′), Yichang (E111°23′ N30°44′), Guangyuan (E105°54′ N32°25′), and Shiyan (E110°54′ N32°36′). Lots of 100 seeds from each of the six provenances were placed in 9-cm petri dishes with a filter paper on the absorbent cotton soaked in 3 ml of distilled water after prechilling for 0, 20, 40, and 60 days at 5℃. Then, the petri dishes were respectively placed in plant growth chamber under conditions of continuous illumination(1200 lx)at 15℃、20℃、25℃ and 30℃. The germination was observed every day for 20 days. Results showed that the suitable temperature range for seed germination in Paulownia tortunei was 20~30℃, while it could be widened to 15~30℃ by prechilling. Seeds of Paulownia tortunei have low winter dormancy, prechilling could accelerate its germination rate and capacity and shorten its mean time to germination, especially at 15℃. Furthermore, the effects of prechilling for 40 days were the greatest, and effects of 20 days and 60 days were relatively small. This indicates that the deepness of seed dormancy in Paulownia tortunei was shallower and chilling for 20 days was not sufficient to release seed dormancy, while 60 days chilling was possibly excessive. The difference in germination rate and capacity of non-chilled seeds in Paulownia tortunei among the six provenances was obvious under conditions of different germination temperature, except for the germination capacity at 25℃. But the difference in mean time to germination was not obvious at 20℃ and 25℃. The germination rate and capacity of non-chilled seeds increased with increasing latitude at 15℃, except for Guilin, but not at suitable germination temperature of 20~30℃. The reasons for germination particularity of seeds from Guilin may be due to the rainfall in Guilin city exceeding other provenances by 600mm. The difference among different provenances was evident in the response to prechilling. The germination rate and capacity of prechilled seeds from southern provenances located in the middle and southern subtropical zone was higher than northern provenances located in the north subtropical zone in Paulownia tortunei. The mean time to germination of prechilled seeds from the provenances of Zhuzhou and Yichang especially located in south and middle subtropical zone was the longest. It became shorter with increasing and decreasing latitude. The characteristics of different shallower dormancy of seeds in Paulownia tortunei from different provenances indicated an eco-physiological adaptation to climate.更多还原