Abstract: Swainsonia salsula was selected and eight treatments (0(CK),80,160,240,320,400,480,560 mmol·L^-1 of NaCl) were designed. Proline (Pro), pyrroline-5-carboxylate synthetase (P5CS), ornithine-oxo-acid transaminase (δ-OAT), and proline dehydragenase (ProDH) of leaves and roots of Swainsonia salsula were analyzed to assess the relationship between proline metabolism and salinity tolerance. The metabolic regularity of proline was revealed. Results show that the root top ratio of Swainsonia salsula was initially increased then decreased under NaCl stress. Proline content increased as the concentration of NaCl increased (P＜0.05). Proline metabolism of Swainsonia salsula seedling was most vigorous under 400 mmol·L^-1 salt stress. The critical threshold of Swainsonia salsula was 400 mmol·L^-1 NaCl. Ornithine as a main synthesis pathway of praline metabolism in Swainsonia salsula seedlings was replaced by glutamate while praline metabolism and the pathway of ornithine remained as auxiliary synergy components with increased NaCl.

Key words: Swainsonia salsula, Proline metabolism, δ-OAT, P5CS, ProDH

摘要： 以苦马豆(Swainsonia salsula Taub.)为试验材料,通过8个不同浓度(0(CK),80,160,240,320,400,480和560 mmol·L^-1 )NaCl胁迫,对苦马豆苗期脯氨酸(Pro)含量及吡咯啉-5-羧酸合成酶(P5CS)、鸟氨酸δ-氨基转移酶(δ-OAT)和脯氨酸脱氢酶(ProDH)活性进行测定,探讨苦马豆对NaCl胁迫的耐受程度和脯氨酸代谢与其耐盐性的关系,以期揭示苦马豆苗期脯氨酸代谢规律,为进一步研究其耐盐性奠定基础。结果表明:在NaCl胁迫下,苦马豆植株根冠比呈现先升高后降低的趋势,苦马豆中脯氨酸含量随NaCl浓度的升高而增大(P＜0.05),在400 mmol·L^-1 NaCl胁迫时,脯氨酸代谢最为旺盛;400 mmol·L^-1 NaCl浓度为苦马豆耐盐阈值。随NaCl浓度的不断升高,苦马豆苗期脯氨酸合成由以鸟氨酸途径为主逐渐转变为以谷氨酸途径为主,鸟氨酸途径为辅的协同合成。

关键词: 苦马豆, 脯氨酸代谢, 吡咯啉-5-羧酸合成酶, 鸟氨酸δ-氨基转移酶, 脯氨酸脱氢酶