在萌发过程中出现于向日葵子叶中的谷氨酰胺合成酶同工酶：光照和硝酸盐的影响。

Glutamine-synthetase isoforms appearing in sunflower cotyledons during germination : Effects of light and nitrate.

机构信息

Departamento de Biologia Vegetal y Ecologia, División de Fisiologia Vegetal, Facultad de Ciencias, Universidad de Córdoba, Avda. San Alberto Magno, E-14004, Córdoba, Spain.

出版信息

Planta. 1992 Mar;186(4):577-81. doi: 10.1007/BF00198038.

DOI:10.1007/BF00198038

PMID:24186788

Abstract

Ion-exchange chromatography has been used to separate the isoforms of glutamine synthetase (GS; EC 6.3.1.2) appearing in sunflower (Helianthus annuus L. cv. Peredovic) cotyledons during seedling growth under different light and nitrogen conditions. Both in dry and imbibed seeds, only a single form of GS (GSs) was detected. Upon seed germination, the GSs isoform was gradually replaced by cytosolic (GS1) and plastidic (GS2) isoforms. Light and nitrate decreased the levels of GS1. In contrast, the appearance of GS2 was greatly stimulated by light. Nitrate also had a positive effect, particularly in the light. Light and nitrate acted synergistically on the appearance of GS2. The GS2:GS1 ratio in cotyledons of 9-d-old seedlings ranged from about 2, in darkness and nitrate-deprivation conditions, to 16 under light and nitrate application. The possible physiological roles of the distinct GS isoforms appearing in the epigeal cotyledons of sunflower during germination, and their differential regulation by light and nitrate, are discussed.

摘要

离子交换色谱法已被用于分离在不同光照和氮条件下生长的向日葵（Helianthus annuus L. cv. Peredovic）子叶中出现的谷氨酰胺合成酶（GS；EC 6.3.1.2）同工型。在干燥和吸胀的种子中，仅检测到一种形式的 GS（GSs）。种子发芽后，GSs 同工型逐渐被细胞质（GS1）和质体（GS2）同工型取代。光照和硝酸盐降低了 GS1 的水平。相比之下，GS2 的出现受到光照的极大刺激。硝酸盐也有积极的影响，特别是在光照下。光照和硝酸盐对 GS2 的出现具有协同作用。在 9 天大的幼苗子叶中，GS2:GS1 的比值从黑暗和硝酸盐剥夺条件下的约 2 变化到光照和硝酸盐处理下的 16。讨论了在萌发过程中出现于向日葵地上子叶中的不同 GS 同工型的可能生理作用及其对光照和硝酸盐的差异调节。