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盐碱混合胁迫对裸燕麦幼苗叶片脯氨酸和多胺代谢的影响

刘建新*,王金成,刘秀丽   

  1. (甘肃省高校陇东生物资源保护与利用省级重点实验室, 陇东学院生命科学与技术学院, 甘肃庆阳 745000)
  • 出版日期:2016-11-10 发布日期:2016-11-10

Effects of salt-alkaline mixed stress on proline and polyamine metabolism in leaves of naked oat seedlings.

LIU Jian-xin*, WANG Jin-cheng, LIU Xiu-li   

  1. (College of Life Science and Technology, Longdong University, Provincial Key Laboratory for Protection and Utilization of Longdong Bioresources in Gansu Province, Qingyang 745000, Gansu, China).
  • Online:2016-11-10 Published:2016-11-10

摘要:

为探讨裸燕麦对盐碱混合胁迫的脯氨酸(Pro)和多胺(PAs)响应机制,采用温室砂培试验,研究了低(25 mmol·L-1)、高(75 mmol·L-1)浓度盐碱混合胁迫0、1、3、5和7 d幼苗叶片Pro和PAs含量及相关代谢酶活性的变化。结果表明:与对照相比,盐碱混合胁迫在整个胁迫期间提高了裸燕麦叶片Pro含量,高浓度胁迫提高的幅度大于低浓度胁迫;低浓度胁迫下吡咯啉-5-羧酸合成酶(P5CS)活性提高,而鸟氨酸-δ-氨基转移酶(δ-OAT)和脯氨酸脱氢酶(ProDH)活性受抑;高浓度胁迫下δ-OAT活性提高,而P5CS和ProDH活性下降,说明低浓度胁迫下Pro合成以谷氨酸途径为主,高浓度胁迫下以鸟氨酸途径为主;低、高浓度盐碱混合胁迫下,游离态腐胺(Put)、亚精胺(Spd)和精胺(Spm)及结合态Spd和束缚态Spd、Spm含量提高,结合态Put、Spm和束缚态Put含量在胁迫1~5 d时提高,胁迫7 d时下降,且高浓度胁迫的变幅大于低浓度胁迫;Put/PAs和(cPAs+bPAs)/fPAs在胁迫1~3 d时提高,胁迫5~7 d时下降或变化不明显,(Spd+Spm)/Put的变化却相反;整个胁迫期间低浓度胁迫保持了较低的Put/PAs和较高的(Spd+Spm)/Put,(cPAs+bPAs)/fPAs除胁迫1 d 时低浓度胁迫低于高浓度胁迫外,其余胁迫时间两浓度处理间差异不显著;精氨酸脱羧酶(ADC)和鸟氨酸脱羧酶(ODC)活性在低、高浓度盐碱混合胁迫期间提高,二胺氧化酶(DAO)活性在胁迫1~3 d下降或变化不大,胁迫5~7 d时升高,多胺氧化酶(PAO)活性的变化与DAO相反,且高浓度胁迫下ADC、ODC、DAO和PAO的变幅大于低浓度胁迫。说明盐碱混合胁迫初期(1~3 d)游离态PAs(fPAs)向结合态和束缚态PAs(cPAs+bPAs)转化增强,低浓度胁迫后期(5~7 d)Put向Spd和Spm转化的能力强于高浓度胁迫,但高浓度胁迫在整个胁迫期间PAs合成和分解的速率更高。
 

关键词: 根系, 籽粒产量, 固定道, 春小麦, 水氮互作

Abstract: To explore the proline and polyamine metabolism-responsive mechanisms of naked oat (Avena nuda) under saltalkaline mixed stress, a naked oat cultivar ‘Dingyou No. 6’ was cultured with perlitesandy pot in greenhouse. The contents of proline and polyamine and the activities of proline and polyaminemetabolizing enzymes of naked oat leaves on 0, 1, 3, 5 and 7 days by the treatments using Hoagland nutrient solution added with mixed saltalkali (molar ratio of NaCl∶Na2SO4∶NaHCO3∶Na2CO3=12∶8∶9∶1) at 25 and 75 mmol·L-1 were investigated after the seedlings had three leaves. The results showed that both low and high levels of saltalkaline stress significantly increased the proline contents in leaves during the whole stress compared with the control, and the increment was higher under the high concentration stress. Activities of pyrroline-5-carboxylate synthetase (P5CS) in leaves were enhanced significantly under the low concentration stress, while the activities of ornithine-δ-aminotransferase (δ-OAT) and proline dehydragenase (ProDH) were inhibited obviously. The δ-OAT activities were enhanced significantly, but P5CS and ProDH activities were decreased obviously under the high concentration stress. These changes demonstrated that the proline in naked oat seedlings was mainly metabolized through the pathway of glutamate under low concentration stress, and an ornithine pathway was predominant under high concentration stress. Moreover, the contents of free putrescine (Put), free spermidine (Spd), free spermine (Spm), conjugated Spd, bound Spd and bound Spm in leaves were increased significantly in the whole period of both levels of stress, and the contents of conjugated Put, conjugated Spm and bound Put were increased significantly in the 1-5 days of saltalkaline stress, but they were obviously decreased on day 7 under the same stress. All of these changes were more obvious under the high concentration stress than that under the low concentration stress. The values of Put/PAs and (cPAs+bPAs)/fPAs were increased significantly in the first 3 days, but decreased or without significant changes in the 5-7 days under the same stress, while the changes of (Spd+Spm)/Put demonstrated the contrary trend. Low concentration stress had lower Put/PAs value and higher (Spd+Spm)/Put value in the whole period, and the (cPAs+bPAs)/fPAs value was lower in the first day under the low concentration stress compared with the high concentration stress; during the 3-7 days, there were no significant differences between the two concentration treatments. Furthermore, the activities of arginine decarboxylase (ADC) and ornithine decarboxylase (ODC) were increased significantly in the whole period under each level of stress, and the diamine oxidase activities in the first 3 days of the stress decreased or slightly changed while a significant increase was observed in the 5-7 days. The change of polyamine oxidase (PAO) activities demonstrated the contrary to the DAO. These changes were much greater under the high concentration stress than under the low concentration stress. All of the results mentioned above suggested that salt-alkaline stress enhanced the capabilities for the transformation of free polyamine to conjugated and bound polyamines in the early period (1-3 days), and the low-concentration stress had stronger capabilities for the transformation of Put to Spd and Spm in the late period (5-7 days) compared with the high concentration stress, while the rate of PAs synthesis and decomposition in the whole period under the high concentration stress was faster than that under the low concentration stress.

Key words: spring wheat, irrigation and nitrogen application, permanent raised bed, grain yield., root