盐胁迫下苜蓿中盐蛋白的诱导产生

The Emergence of Salt-Induced Proteins in Alfalfa Under NaCl Stress

盐胁迫下苜蓿叶片中蛋白质的合成受到抑制,而其离体叶绿体中蛋白质合成增强,ABA阻碍了后者的蛋白质合成。NaCl胁迫下,“松江”和“肇东”两品种的根和叶中均无新多肽出现。在盐敏感的“松江”品种离体叶绿体中,NaGl诱导70,65,60和43kD4种多肽产生,ABA诱导60和17kD两种多肽产生;在较抗盐的“肇东”品种离体叶绿体中,NaGl诱导83,80kD和43kD3种多肽产生,但100mmol/L NaCl并不诱导83kD多肽出现,ABA无明显作用。两品种的43kD多肽和肇东品种的80kD多肽都存在于类囊体膜上,而松江品种的60kD多肽则存在于叶绿体间质中。

The effect of salt stress on the pattern of protein synthesis and the emergence of salt-induced proteins was investigated in salt-sensitive Songjiang and salt-tolerant Zhaodong alfalfa. The incorporation of ~3H-Leu indicated that protein synthesis was inhibited in leaves and enhanced in isolated chloroplasts under NaG1 stress. The effect of ABA on the incorporation of ~3H-Leu into isolated chloroplast proteins was also examined. No new polypeptides were detected in roots and leaves in the presence of NaCl and ABA. In isolated chloroplasts, four polypeptides (70, 65, 60 and 43 kD) were induced by NaCl, and two (60 and 17 kD) by ABA in var. Songjiang; three (83, 80 and 43 kD) by NaCl (but 83 kD polypeptides were not found with 100 mmol/L NaCl), and ABA did not affected notably in var. Zhaodong. 43 kD polypepfide was located in the thylakoid membrane in both varieties and 80 kD polypeptide was so in var. Zhaodong; 60 kD polypeptide in var. Songjiang was detected in chloroplast stroma. This fact indicated that ABA induced only the emergence of salt-induced proteins in chloroplast stroma, while NaCl induced the emergence of salt-induced proteins in chloroplast stroma and thylakoid membrane.