摘要
为探讨H_2O_2对盐碱胁迫下植物脯氨酸代谢的调控机理,以燕麦新品种‘定莜6号’幼苗为材料,采用水培法研究了外源H_2O_2对混合盐碱胁迫下燕麦脯氨酸积累和代谢途径的影响。结果表明,75 mmol·L-1混合盐碱（Na Cl∶Na_2SO_4∶Na HCO_3∶Na_2CO_3=12∶8∶9∶1）胁迫可促进燕麦幼苗叶片脯氨酸的积累,提高脯氨酸合成的鸟氨酸途径关键酶鸟氨酸δ-氨基转移酶（δ-OAT）活性,抑制脯氨酸合成的谷氨酸途径关键酶Δ1-吡咯啉-5-羧酸合成酶（P5CS）及脯氨酸降解限速酶脯氨酸脱氢酶（Pro DH）活性。在75 mmol·L-1混合盐碱胁迫下添加0.01～1 000μmol·L-1H_2O_2可显著提高燕麦幼苗叶片的脯氨酸含量,其中10μmol·L-1H_2O_2的作用最明显;10μmol·L-1H_2O_2上调了75 mmol·L-1混合盐碱胁迫下燕麦幼苗叶片的P5CS和δ-OAT活性,降低了Pro DH活性。此外,10μmol·L-1H_2O_2使75 mmol·L-1混合盐碱胁迫下燕麦幼苗叶片内源性H_2O_2含量急剧升高后迅速降低。表明外源H_2O_2能够提高混合盐碱胁迫下燕麦幼苗内源H_2O_2的含量,并通过活化脯氨酸合成的谷氨酸途径和鸟氨酸途径,抑制脯氨酸的降解,促进混合盐碱胁迫下燕麦幼苗脯氨酸的积累。
Saline-alkali stress interferes with cell metabolism,and inhibits plant growth and development.Proline metabolism is closely related with plant salt-alkali resistance. As signaling molecules,hydrogen peroxide（ H_2O_2） plays vital roles in the regulation of plant cell metabolism,as well as in adaptation to the environmental stress. In order to understand the regulatory mechanism of exogenous H_2O_2 on proline metabolism in oat（ Avena nuda） under salinity-alkalinity stresses,the ‘Dingyou No. 6 ＇（ a new oat cultivar） seedlings with two leaves were used to investigate the effects of exogenous H_2O_2 on proline accumulation in leaves of the seedlings under complex saline-alkali stress by the method of solution culture. The results showed that 75 mmol·L- 1complex saline-alkali stress（ molar ratio of Na Cl∶ Na_2SO_4∶ Na HCO_3∶ Na_2CO_3= 12∶8∶9∶1） led to a significant accumulation of proline in leaves,and induced a rapid increase of activities of the key enzymes ornithine-δ-aminotransferase（ δ-OAT） of proline biosynthesis,and a decrease of activities of the key enzymes Δ1-pyrroline-5-carboxylate synthetase（ P5CS） of proline biosynthesis,as well as the key enzyme proline dehydrogenase（ Pro DH） of proline degradation. Moreover,treatments with 0. 01- 1 000 μmol · L- 1,especially,10 μmol · L- 1H_2O_2 couldenhance the accumulation of proline in oat seedling leaves under complex saline-alkali stress. H_2O_2 of 10 μmol·L- 1also increased the activities of P5 CS and δ-OAT,and decreased the activity of Pro DH in leaves under complex saline-alkali stress. In addition,10 μmol·L- 1H_2O_2 treatments could rapidly increase the endogenous H_2O_2 levels in oat seedling leaves under complex saline-alkali stress. The exogenous H_2O_2 treatment resulted in the increase of endogenous H_2O_2 content in oat seedlings under complex saline-alkali stress. H_2O_2 induced proline accumulation might be a combined result of the activation of glutamate and ornithine pathways of proline biosynthesis and inhibition of proline degradation pathway.
出处
《植物研究》
CAS
CSCD
北大核心
2016年第3期427-433,共7页
Bulletin of Botanical Research
基金
甘肃省庆阳市科技计划项目(KZ2014-19)资助~~
关键词
燕麦
混合盐碱胁迫
过氧化氢
脯氨酸代谢
oat
complex saline-alkali stress
hydrogen peroxide
proline metabolism
