不同种源红桦种子的萌发特性

以陕西、宁夏、甘肃、青海4省7个种源地红桦种子为对象，测定各种源地红桦种子的千粒重、形态特征及在不同温度（30℃、25℃、20℃、15℃）和不同光照（无光照0 h、半光照/半黑暗12 h/12 h、全光照24 h）条件下的萌发率与萌发特性，并与千粒重、环境因子进行相关性分析。结果表明，各种源千粒重大小为:凤县＞泾源＞宁陕＞礼县＞洛南＞太白＞湟中，洛南县、太白县和湟中县红桦种子的千粒重与其他种源存在显著差异；25℃为红桦种子最适萌发温度。在15℃下，各种源红桦种子几乎不萌发。25℃下，各种源红桦种子萌发率显著高于其他温度；光照和光照时长都可以显著提高红桦种子的萌发率。全光照（24 h）下各种源红桦种子萌发率显著高于半光照/半黑暗（12 h/12 h）和全黑暗（0 h）条件；红桦种子萌发率与种子的千粒重呈显著正相关（P=0.046＜0.05）,与种源的海拔呈极其显著的负相关（P=0.004＜0.01）；红桦种子萌发率与种源的年日照时长（P=0.064＞0.05）和年降雨量（P=0.93＞0.05）都没有相关性。

Germination Characteristics of Betula albo-sinensis Seeds from Different Provenances

Betula albo-sinensis seeds from seven provprovenances in Shaanxi,Ningxia,Gansu and Qinghai provinces were used as research objects to determine the thousand-grain weight (TGW),morphological characteristics,and germination characteristics under different temperatures (30,25,20,and 15℃) and different light conditions (no light 0 h,semi-light/semi-dark 12 h/12 h,full light 24 h).The correlation between germination rate,TGW and environmental factors were analyzed.The TGW of the seeds from different provenances was in the order of Fengxian＞Jingyuan＞Ningshan＞Lixian＞Luonan＞Taibai＞Huangzhong.The values of TGW of the seeds from Luonan,Taibai and Huangzhong were significant different with those from other provenances.At the temperature of 15℃,almost all the seeds did not germinate.At 25℃,the germination rate of seeds were significantly higher than other temperatures,indicating that the optimal temperature for the germination of B.albo-sinensis seeds was 25℃.Illumination and long time period illumination could significantly increase the seeds germination rate.Under the full light (24 h) condition,the germination rate was significantly higher than that of semi-light/semi-dark (12 h/12 h) and no light (0 h) conditions.The germination rate was significantly and positively correlated with the TGW (P=0.046<0.05).The seed germination rate was significantly and negatively correlated with the elevation (P=0.004<0.01).No correlation was found between the germination rate and the annual sunshine duration (P=0.064>0.05) and annual rainfall (P=0.93>0.05).