探讨不同裸层积处理方式和时间对红松（Pinus koraiensis Sieb. et Zucc.）种子形态发育、各部位抑制物生理活性以及萌发率的影响，并确定最佳裸层积处理条件。

采用恒温、暖温转低温以及低温转日变温等条件下9种不同的裸层积处理方式，将新鲜成熟的红松种子置于人工控温环境中进行层积处理，暖温温度为20 ℃，低温温度为5 ℃，日变温温度为20 ℃/12 h + 5 ℃/12 h ，湿度控制在60%，层积时间持续20周，每4周取样测定种子胚长、胚率、胚质量比、萌发率以及中种皮和种仁抑制物生理活性。

①层积结束时，暖温20周、日变温20周以及3种暖温转低温处理，胚长和胚率均显著增加；3种低温转日变温处理，日变温层积时间越长，胚长和胚率越大；低温20周处理种子胚长和胚率最小；经过20周层积处理，各处理胚质量比均比层积起始有所上升，层积结束时，暖温20周以及3种暖温转低温层积处理，胚质量比均超过5%，而其余处理胚质量比均低于5%。②在层积结束时，暖温20周、低温20周以及日变温20周处理种子基本不发芽，暖温8周转低温12周处理萌发率虽略低于暖温12周转低温8周处理，但其发芽指数显著大于暖温12周转低温8周处理，且其发芽时间最短。③层积结束时，中种皮浸提液原液抑制物活性明显减弱，但种仁浸提液原液抑制物活性依然较强。④相关分析显示，只有胚长和胚质量比与红松种子萌发率之间呈显著正相关关系，胚率以及抑制物活性与红松种子萌发率之间并无显著相关关系。

裸层积暖温8周转低温12周处理的红松种子萌发效果最好，暖温处理有利于红松种子后熟生长，低温处理有利于生理休眠的解除。

This study is to investigate the effects of different treatments and a period of naked seed stratification on seed morphological development, physiological activity of inhibitors, and seed germination rate in Pinus koraiensis Sieb. et Zucc （Korean pine）; and to determine the optimal conditions for naked seed stratification.

Nine naked seed stratification methods were used to treat Korean pine seeds, along with constant temperature, warm (20 ℃) to low (5 ℃) temperature, and low to diurnal variable temperature conditions (12 h at 20 ℃, 12 h at 5 ℃). Fresh, mature seeds of Korean pine were soaked in water for 5 days and disinfected, then placed in a temperature-controlled environment for stratification. Humidity was maintained at approximately 60% and the stratification period lasted for 20 weeks. During the stratification process, samples were taken every 4 weeks to measure the seed embryo length, embryo length to kernel length ratio, embryo dry weight to kernel dry weight ratio, germination percentage, germination index, mean germination time, and physiological activity of the middle seed coat and seed kernel inhibitors. The physiological activity of the inhibitors was measured with cabbage (Brassica campestris L. ssp. chinensis) seeds as the recipient plants, and the germination rate of the cabbage seeds was determined after 24 h.

①At the end of the stratification period, the 20 weeks treatments of warm temperature, diurnal variable temperature, and three different treatments of warm to low temperature, embryo length and the embryo length to kernel length ratio of Korean pine seeds were significantly increased. Under the three low temperature to diurnal variable temperature treatments, longer diurnal variable temperature stratification periods resulted in greater embryo lengths and embryo length to kernel length ratios. Embryo length and embryo length to kernel length ratios of Korean pine seeds were minimized after 20 weeks of a low temperature treatment. The warm temperature treatments, diurnal variable temperature treatments, and the three warm to low temperature treatments all resulted in embryos greater than 9 mm in length. The treatment of warm temperature for 12 weeks followed by low temperature for 8 weeks resulted in the longest embryo (10 mm), followed by the treatment of warm temperature for 8 weeks followed by low temperature for 12 weeks, which produced an embryo of 9.91 mm length. Warm temperature, diurnal variable temperature, the 4 weeks low temperature and 16 weeks diurnal variable temperature, and the three warm temperature to low temperature treatments all resulted in embryo length to kernel length ratios above 74%. The 12 weeks warm temperature and 8 weeks low temperature treatment had the largest embryo length to kernel length ratio (81.82%), followed by the 8 weeks warm temperature and 12 weeks low temperature treatment (78.62%). The embryo dry weight to kernel dry weight ratio increased following the 20 weeks of stratification for all embryos. At the end of the stratification periods, the 20 weeks warm temperature treatment and the three warm temperature to low temperature treatments resulted in embryo dry weight to kernel dry weight ratios greater than 5%. The 8 weeks warm temperature and 12 weeks low temperature treatment had the largest embryo dry weight to kernel dry weight ratio (5.83%), while the embryo dry weight to kernel dry weight ratio in the other treatments was less than 5%.②After 16 weeks of stratification, the 4 weeks warm temperature and 16 weeks low temperature treatment and the 8 weeks warm temperature and 12 weeks low temperature treatment were the only treatments with germination rates exceeding 10%; the 8 weeks warm temperature and 8 weeks low temperature treatment had the highest germination rate (25%). Twenty weeks of stratification increased the germination percentage of the three warm temperature to low temperature treatments significantly, but the germination percentage of the other treatments was less than 10%, and some did not germinate. Among these treatments, the 12 weeks warm temperature treatment, followed by 8 weeks low temperature treatment yielded the highest germination percentage (57.0%)； next，the 8 weeks warm temperature treatment followed by 12 weeks low temperature treatment, with a germination percentage of 54%. At the end of the stratification period, although the germination percentage of the 8 weeks warm, 12 weeks low temperature treatment was slightly lower than that of the 12 weeks warm, 8 weeks low temperature treatment, the germination index of the former was significantly higher than that of the latter, and the mean germination time was shortest for the former.③After 20 weeks of stratification, the inhibitor activity of the middle seed coat extract decreased significantly, but the inhibitor activity of the kernel remained strong. The germination percentage of the cabbage seeds in the middle seed coat extract for each stratification treatment was as low as 33%, but germination was effectively eliminated in the seed kernel extract.④Significant positive correlations were observed between Rorean pineseed germination percentage and embryo length, as well as between seed germination rate and embryo dry weight to kernel dry weight ratio. No significant correlation was observed between embryo length to kernel length ratio and inhibitory activity and Korean pine seed germination percentage.

The warm temperature treatment was conducive to the ripening growth of Korean pine seeds, and the low temperature treatment was beneficial to the release of physiological dormancy. The optimal germination percentage was achieved by stratification treatment at warm temperature for 8 weeks, followed by low temperature for 12 weeks.