荒漠半灌木白滨藜种子的萌发特性及其生态意义

白滨藜是具有抗旱、抗盐碱和耐贫瘠能力的半灌木，为新疆地区的良等牧草。通过研究温度、贮藏时间、苞片及盐分对白滨藜种子萌发的影响，结果表明：白滨藜种子萌发的最适温度为20／30℃和25／35℃。室温干藏2～8个月显著提高种子的萌发速率，干藏10个月后，种子萌发速率与萌发率显著降低。苞片延缓种子吸胀，对种子的最终萌发率有显著影响；去除苞片可以明显促进种子的萌发。浓度低于0．8 mol／L 的 NaCl 溶液对种子萌发的影响不大；但从0．8 mol／L 起萌发率随着浓度增高而降低，直至为零；将在0．05～4．00 mol／L 盐溶液中处理的种子转移至蒸馏水后，仍有一定的萌发恢复率，表明 NaCl 处理后的部分种子有保持活力的能力，部分种子丧失活力。对白滨藜种子萌发特性的研究，为揭示其萌发行为进化和生态适应机制提供科学依据，也为新疆荒漠盐碱地区饲用半灌木引种改良，良种繁育提供基础资料。

Seed germination characteristics of the desert subshrub Atriplex cana and its ecologi-cal significance

Atriplex cana is a xerophytic subshrub with drought resistance,salinity resistance and low fertility tolerance.It is a useful forage plant in Xinjiang.Experiments were conducted to determine the effects of tem-perature,seed bract removal,and NaCl on seed germination.Seeds were able to germinate in a range of tem-peratures from 5/15℃ to 25/35℃.The higher the temperature,the faster the germination occurred.The opti-mum temperature regime for seed germination was 20/30℃ and 25/35℃.Under a 25℃ dark/35℃ light re-gime,the final germination percentage reached a maximum value after 6-8 days of hydration,while under 5/15℃ and 10/20℃ temperature regimes final germination percentage was achieved after 25-34 days.There was a significant increase in seed germination rate after 2-8 months seed storage,while germination percentage of seeds decreased when exposed to natural atmospheric conditions for 10 months.Bracts formed a mechanical barrier to water uptake,and has a significant influence on the final seed germination rate.Removal of bracts promoted seed germination.Germination was not affected by NaCl at concentrations below 0.8 mol/L,but was decreased by NaCl at higher concentrations.Seeds incubated in NaCl at concentrations of 0.05-4.00 mol/L re-covered after being transferred to distilled water.After NaCl treatment some seeds retained their vigor,while others lost vigor.Research into seed germination characteristics may reveal a scientific basis for this ecological adaptation trait.Such research may also provide basic data for improvement salinity tolerant forage subshrub production in the Xinjiang desert.