干旱沙区不同种源的绵毛优若藜表现性比较

在民勤沙生植物园．通过室内和田间试验，对引自美国西部沙漠区和草原区的绵毛优若藜的物候期、种子发芽温度、植物的生长和地上部分营养成分进行了观测与测定。在昼夜变温条件下，草原区种子对温度的反应较迟钝．适宜的发芽温度应为5～25C；沙漠区种子发芽适宜的温度为lO～30C。两个种源的绵毛优若藜均在6～7月间生长量最大。草原区种源的植株月平均生长量大于沙漠区种源的生长量。不同种源植物的物候期相差较小，除开花期外，沙漠区植物的展叶、孕蕾、结果和叶变色均早于草原区。在民勤沙区，绵毛优若藜表现为准常绿性。沙漠区植株的营养成分含量略低于草原区植株。

Performances of Ceratoides lanata Plants of Different Seed Sources in Arid Desert Regions

Indoor and field experiments were conducted in Minqin Psammophyte Garden to investigate the phenophases, germination temperatures and growths of Ceratoide. lanata, which were introduced from the desert region and grassland region of the United States, as well as determine the nutrient contents of its aboveground parts. With different temperatures adopted in daytime and nighttime, the seeds introduced from the grassland region showed a slow response to temperature and their optimal germination temperature ranged between 5 C and 25 C ; the optimal germination temperature of the seeds introduced from the desert region varied between 10 C and 30 C. The plants of Ceratoides lanata of different sources presented the highest growth between June and July. The plants from the seeds introduced from the grassland region had higher monthly growth rate than those from the seeds introduced from the desert region. The plants of different seed sources slightly differed in phenophase with the plants from the seeds of the desert region opening their leaves, budding, fruiting and changing leaf color earlier than those from the seeds of the grassland region except at the flowering stage. In the desert region of Minqin County, Ceratoides lanata appears to be a quasi-evergreen. The nutrients of the plants from the seeds of the desert region were slightly lower than those of the plants from the seeds of the grassland region.