中文摘要：

为揭示土壤种子库种子萌发对外界环境变化的响应策略，设计储藏方式和温度对古尔班通古特沙漠3种十字花科植物菥冀、庭荠和条叶庭荠种子萌发影响。2个萌发温度（5℃／15℃、15℃／25℃）下，以室温干藏种子为对照，设置5种储藏处理（干种子：冬季室外干藏、冬季室外沙埋；吸胀种子：4℃、-10℃、冬季室外沙埋）及添加外源GA。的萌发实验。结果表明，1）5℃／15℃萌发条件下，与对照相比，各储藏处理都显著延长了菥冀和庭荠初始萌发时间，冬季室外沙埋干藏处理显著降低了庭荠种子萌发率。15℃／25℃萌发条件下，4℃、湿藏处理显著延长了3种种子初始萌发时间，同时显著抑制条叶庭荠种子萌发；各储藏处理下菥莫种子初始萌发时间显著缩短，对萌发率无影响。2）添加GAs可使各储藏处理下种子萌发进程由停滞状态转变为持续萌发。3）各储藏处理和对照中菥冀和庭荠种子的潜在萌发率均超过50％，5℃／15℃温度下大量条叶庭荠种子腐烂或失去活力导致潜在萌发率低于20％；添加GA3对3种种子潜在萌发率贡献不同。

英文摘要：

In order to understand the responses of seedlings emerging from the soil seed bank to outside environmental conditions, we studied effects of storage condition and temperature on germination of three Brassicaceae species in Gurbantunggut desert, including Thlaspi arvense, Alyssum desertorum and Alyssum linifolium.Taking dry seeds stored at room temperature as control, five different storage conditions were applied in our study, including （a）dry seeds stored outside in winter; （b）dry seeds buried in soil in winter; （c） imbibed seeds stored at 4 ℃ ; （d）imbibed seeds stored at -10℃ ; and （e） imbibed seeds buried in soil in winter. After storage,seeds were incubated at 5℃/15℃ or 15 ℃/25℃ for germination.Effect of exogenous GA3 on seed germination was also studied. Our results showed that （1） under 5℃/15℃ regime,comparing to the control, each storage treatment significantly in- creased initiatory time of seed germination for Th.Arvense and A.desertorum,germination percentage of the dry seeds buried in soil in winter for A.desertorurn was significa tion time and germination percentage of Th.arvense,A.desertorurn and and increased at 15 ~C/25 ~C, respectively. In addition, under 15 ℃/25 nt A y reduced; initial germina- linifolium were shortened ℃ regime,initial germination time and germination percentage of imbibed seeds stored at 4℃ for A.linifolium were significantly prolonged and inhibited, respectively. （2） Exogenous GA3 facilitated consistent germination of stored seeds. （3） Germination potential of. Th.Arvense and A.desertorum exceeded 50 % under all storage con- dition. At 5 ℃/15 ℃, germination potential of A.linifolium was lower than 20% ,due to the fact that many seeds decayed or lost viability under this temperature regime. The contribution of exogenous GA3 to potential germination varied among these 3 species.