紫花苜蓿种子对逆境贮藏条件的反应

Response of alfalfa seed to stress storage conditions.

以陇东紫花苜蓿 (MedicagosativaL .cv .“Longdong”)种子为材料 ,在室温、35℃和 35℃ +10 %的种子含水量 (SMC) 3种贮藏、接种或不接种燕麦镰刀菌 (Fusariumavenaceum (Fr.)Sacc .)的条件下 ,1年贮藏期内对各逆境处理的种子每隔 6 0d进行 1次标准发芽试验 ,2 0℃恒温、第 10d统计种子的发芽率和死亡率 ,试验结束时计测种子幼苗的长度和感病率 ;在大田条件下观测各处理种子的出苗率 ,确定催腐 (CD)与各种贮藏条件下的苜蓿种带真菌种类和检出率 .结果表明 ,随着贮藏温度和种子含水量等逆境贮藏条件胁迫的加剧 ,苜蓿种带真菌检出率逐渐增高 ,从室温、35℃条件下的 10 %上升到CD +35℃ +10 %SMC条件下的 2 9% ;抗病性逐渐减弱 ,35℃ +10 %SMC条件下幼苗的感病率和种子死亡率显著 (P <0 .0 5 )高于室温和 35℃下的感病率和种子死亡率 ;室内种子发芽率和田间出苗率逐渐下降 ,35℃ +10 %SMC条件下的种子的发芽率和田间出苗率显著 (P <0 .0 5 )低于在室温和 35℃下的发芽率和田间出苗率 ;幼苗生长受到抑制 ,35℃ +10 %SMC条件下的苗长和根长显著 (P <0 .0 5 )低于在室温和 35℃下的幼苗长度 .随着贮藏时间的延长 ,种子真菌检出率和田间出苗率下降 ,幼苗感病率增加 .与未接种的对照相比 。

The seed germination rate, seed mortality, seedling length, and infection rate of alfalfa ( Medicago sativa L.cv.'Longdong') were measured at constant temperature 20℃ every 60 days during one year storage period after inoculated or no inoculated by Fusarium avenaceum under room temperature (RT),35℃,and 35℃ and +10% seed moisture content (SMC) conditions. Field emergence rates of seeds under above treatments were also observed,and seed borne fungi were detected under the conditions mentioned above and controlled deterioration (CD) as well. The results showed that the percentage of isolated alfalfa seed borne fungi was increased from 10% under room temperature and 35℃ to 29% under 35℃+10%SMC .Disease resistance was declined, and seed mortality and seedling infection rate under 35℃+10%SMC were significantly higher than those under room temperature and 35℃ respectively (P<0.05). The seed germination rate and field emergence rate were also decreased significantly (P<0.05). Seedling shoot and root length under 35℃+10%SMC were significantly less than those under RT and 35℃ respectively (P<0.05).The percentages of both seed borne fungi isolated and field emergence were decreased,and that of seedling infection was increased with storage period extending from 60 to 360 days. Compared to no inoculated control,the percentage of seed germination, seedling shoot and root length were decreased, and seed mortality and seedling infection rate were increased after inoculated by F.avenaceum .