Abstract: The hard-seededness and stress resistance of Ammopiptanthus mongolicus seeds were studied in this paper to provide a theoretical basis for the research of cultivation and domestication.Seeds were imbibed one to five days as T₁,T₂,T₃,T₄ and T₅ treatments,respectively.Seeds not imbibing water after five days are defined as hard-seed(T_r) control.Results show that the germinating energy,germination index,vigor index and soluble protein content increase,while the relative conductivity and Malonaldehyde(MDA) content decrease with hard-seededness increasing.Effects of different treatments for breaking hard-seeds indicate that seeds soaked in 80℃ water are the best.The superoxide dismutase(SOD) activity,peroxidase(POD) activity,catalase(CAT) activity and proline content of different levels of hard-seeds were compared under drought stress and salt stress.Under the same stress conditions,the values of most indexes increase.Under certain conditions,the enzyme activities and proline content of hard seeds are significantly higher than other seeds(P<0.01).This study indicates that hard seeds have a more protective enzyme system.The resistance of drought and salt is enhanced for hard-seeds.

Key words: A.mongolicus seeds, Hard-seededness, Enzyme activity, Drought stress, Salt stress

摘要： 将1~5 d内每天吸胀的沙冬青(Ammopiptanthus mongolicus)种子视为不同硬实程度的种子T₁,T₂,T₃,T₄和T₅,与第5 d仍未吸胀的硬实种子(记作T_r)作为试材对其硬实特性和抗逆性进行研究,以期为沙冬青种子栽培驯化提供理论依据。结果表明:随着硬实程度的提高,种子的发芽势、发芽指数、活力指数呈上升趋势;电导率和丙二醛(MDA)含量逐渐下降;可溶性蛋白含量逐渐上升。不同处理对种子的硬实破除效果表明,80℃热水浸泡种子可达到最佳破除效果。通过测定模拟干旱胁迫和盐胁迫下不同硬实程度种子的超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性和脯氨酸(Pro)含量,表明在相同逆境条件下,随硬实程度的加深,除极个别外,各项指标值均有不同程度的升高,且一定胁迫强度下硬实种子萌发幼苗的各酶活性和脯氨酸含量均极显著高于其他萌发幼苗(P<0.01),因此,硬实种子比非硬实种子有较强的保护酶调节系统。硬实程度越高,耐旱和耐盐能力也随之升高。

关键词: 沙冬青种子, 硬实特性, 酶活性, 干旱胁迫, 盐胁迫