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 ecological significance

Abstract: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 temperature, seed bract removal, and NaCl on seed germination. Seeds were able to germinate in a range of temperatures from 5/15℃ to 25/35℃. The higher the temperature, the faster the germination occurred. The optimum temperature regime for seed germination was 20/30℃ and 25/35℃. Under a 25℃ dark/35℃ light regime, 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 recovered 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.