PEG胁迫及复水对不同抗旱性小麦幼苗脯氨酸代谢关键酶活性的影响  

Effects of PEG Stress and Recovery on Activities of Key Enzymes Involved in Proline Metabolism in Wheat Cultivars with Difference in Drought Tolerance

作　　者：姜淑欣[1] 刘党校[1] 庞红喜[2] 吕金印[1] 

机构地区：[1]西北农林科技大学生命科学学院,陕西杨陵712100 [2]西北农林科技大学农学院,陕西杨陵712100

出　　处：《西北植物学报》2014年第8期1581-1587,共7页Acta Botanica Boreali-Occidentalia Sinica

基　　金：国家自然科学基金项目(31271624)

摘　　要：以两种不同抗旱性小麦品种幼苗为试验材料,采用PEG模拟干旱胁迫处理,探究干旱胁迫及复水对小麦幼苗叶片与根系脯氨酸累积及关键酶活性的影响。结果显示:(1)PEG胁迫下抗旱品种‘普冰143’根长和根干重下降不大,而水敏感品种‘郑引1号’根长和根干重下降显著;且于胁迫处理36h时‘普冰143’根系脯氨酸含量增加(75.0%)显著大于‘郑引1号’(37.7%),复水24h后均恢复至对照水平。(2)PEG胁迫下‘普冰143’叶片中谷氨酸合成途径关键酶P5CS和鸟氨酸合成途径关键酶δ-OAT活性均显著增加,且‘普冰143’叶片脯氨酸两条合成途径关键酶活性均得以加强;PEG胁迫处理36h时,‘郑引1号’叶片中P5CS活性增加显著,δ-OAT活性变化较小,且‘郑引1号’叶片脯氨酸合成可能以谷氨酸途径为主;但在PEG胁迫下两个不同抗旱性品种的根中P5CS、δ-OAT活性均变化较小。(3)PEG胁迫处理36h时‘普冰143’叶片脯氨酸降解酶PDH活性显著下降,而‘郑引1号’叶片PDH活性显著增加,复水后抗旱品种叶片该酶活性显著增加,水敏感品种恢复至对照水平;但PEG胁迫处理下两个不同抗旱性品种的根中PDH活性均显著下降。研究表明,PEG胁迫下小麦叶片是合成脯氨酸的主要部位,抗旱品种‘普冰143’根系脯氨酸持续积累与叶片中高的脯氨酸合成关键酶活性及脯氨酸转运有关。The contents of proline and activities of key enzymes involved in proline metabolism in the leaves and roots were investigated for two wheat cultivar seedlings（differing in drought tolerance）exposed to PEG-6000 stress and recovery.The results showed that：（1）The root length and the root dry weight of‘Pubing 143＇（drought tolerant）were little affected little by PEG stress,whereas the root length and the root dry weight of‘Zhengyin 1＇（drought sensitive）decreased significantly.Under PEG stress the increasing range（75.0%）of proline content in the roots of‘Pubing 143＇was more than that in‘Zhengyin 1＇（37.7%）at 36 hand the proline contents of both genotypes tended to be equal to their respective control after recovery from drought;（2）The activities of P5CS（synthesize proline from glutamate）andδ-OAT（synthesize proline from ornithine）increased significantly in the leaves of‘Pubing 143＇under PEG stress,which indicated that two biosynthetic pathways were enhanced in the drought-tolerance cultivar‘Pubing143＇under PEG stress.P5 CS activity increased while the change ofδ-OAT activity was not obvious in‘Zhengyin 1＇at 36 h,which indicated that the leaves of drought-sensitive cultivar‘Zhengyin 1＇synthesized proline from ornithine primarily under PEG stress.Under PEG stress the activities of P5 CS andδ-OAT were less affected in both wheat varieties roots;（3）PDH activity had a significant decrease at 36 hunder PEG stress and increased significantly after recovery in the leaves of‘Pubing 143＇.PDH activity increased significantly compared with control in leaves of‘Zhengyin 1＇under PEG stress.However,the activity of PDH decreased significantly in both wheat varieties roots.These results suggested that proline was mainly synthesized in the leaves of wheat and the accumulation of proline in the roots of‘Pubing 143＇was associated with increased P5 CS activity in leaves and transport of proline.

关 键 词：PEG胁迫 小麦 吡咯啉-5-羧酸合成酶 鸟氨酸δ-氨基转移酶 脯氨酸脱氢酶 

分 类 号：Q945.78[生物学—植物学]