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作 者 ：杜晓濛1，李 菁1,2，田向荣1,2*，李朝阳1

期 刊 ：西北植物学报 2012年 11期 页码：2279~2285

关键词：脱水与复水；藓类；活性氧；脂质过氧化；脱水耐性；

Keywords:dehydration and rehydration, bryophytes, reactive oxygen species (ROS), lipid peroxidation, desiccation tolerance,

摘 要 ：以来自不同水分生境的金发藓和湿地匐灯藓为材料，对二者在脱水与复水胁迫条件下的活性氧代谢、脂质过氧化损伤程度及其抗氧化系统应答的差异进行比较研究。结果显示：在脱水与复水过程中，（1）硅胶快速脱水更接近阳光直射条件下藓类植物的水分丧失。（2）随着含水量的变化，湿地匐灯藓虽然能够在复水后迅速修复细胞的完整性，但变化剧烈；金发藓则能够始终维持较低的膜透性。（3）2种藓类植物的丙二醛（MDA）含量变化均呈先升后降趋势，但金发藓的MDA含量明显低于湿地匐灯藓。（4）2种藓类植物的超氧阴离子自由基（O^-·₂）产生速率和过氧化氢含量（H₂O₂）的变化均与MDA含量变化相似，且金发藓活性氧水平明显高于湿地匐灯藓。（5）2种藓类植物的超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和抗坏血酸过氧化物酶（APX）活性受活性氧诱导亦呈先升后降的趋势，但金发藓抗氧化酶对活性氧迸发的应答更快，活性更强。（6）2种藓类植物的抗坏血酸（AsA）含量呈先降后升态势，但金发藓的含量低于湿地匐灯藓。研究表明，来自不同生境的2种藓类植物对脱水胁迫所致的氧化胁迫均具有很强的适应能力，尤其是复水过程中的修复能力，但不同藓类可能通过不同途径和机制来适应脱水所致的氧化胁迫；来自易发生水分亏缺生境的金发藓可能因具有更强抗氧化能力，从而获得比来自水分充沛生境的湿地匐灯藓更高的脱水耐性。

Abstract:Polytrichum commune from relative drought habitat and Plagiomnium acutum from wet habitat were used as materials,their difference in reactive oxygen species metabolism,lipid peroxidation and response of antioxidative system were studied under dehydration and rehydration stress.(1)During process of dehydration and rehydration,moisture content alternation under summer sunlight is similar to changes on silica gel fast desiccation.(2)Membrane permeability of P.acutum recovered rapidly after rehydration,but its alternation was dramatic.On contrary,permeability of P.commune sustained a stable lower level.(3)In the procedure of desiccation and rehydration,malondiadehyde (MDA) content of both bryophytes displayed opposite trends of moisture content alternation,that is to say,increased under desiccation and then decreased under rehydration,and content in P.commune was obviously lower than that in P.acutum.(4)During dehydration and rehydration,superoxide anion (O^-·₂) reproductive rate and hydrogen peroxide (H₂O₂) content of both species manifested a tendency similar to MDA content,and their value in P.commune was obviously higher than that in P.acutum.(5)Induced by ROS,activities of antioxidative enzymes of both bryophytes,such as superoxide dismutase (SOD),catalase (CAT) and ascorbic peroxidase (APX) manifested the same tendency of ROS alternation,in other words,possessed a peak during dehydration and rehydration,and their activities in P.commune was much more sensitive to dehydration oxidative stress than that in P.acutum.(6)The ascorbic acid (AsA) content decreased under desiccation and then increased under rehydration, and content in P.commune was obviously lower than that in P.acutum.Results mentioned above indicated that both bryophytes contains powerful ability to adapt desiccation oxidative stress,especially,the repair ability in rehydration process.Nevertheless,bryophytes from deferent habitat should reflect distinct response on desiccation.P.commune from relative drought habitat possess stronger desiccation tolerance than P.acutum from wet habitat for its higher antioxidtive ability.

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