渗透胁迫与大豆幼苗叶片多胺含量的关系

Relationship between osmotic stress and polyamine levels in leaves of soybean seedlings

用高效液相色谱(HPLC)法对渗透胁迫下两个抗旱性不同的大豆品种(抗旱性弱的豫豆6号和抗旱性强的豫豆24号)幼苗叶片的三种不同形态多胺游离态(Free:f)、酸可溶性共价结合态(Acid soluble covalently conjugated:AS-CC)和酸不溶性共价结合态(Acid insoluble covalently conjugated:AISCC))的含量变化进行了研究。结果如下:三种游离态多胺:腐胺(fPut)、亚精胺(fSpd)和精胺(fSpm)均在渗透胁迫条件下上升,但是豫豆24号的fSpd和fSpm的上升幅度明显大于豫豆6号,而豫豆6号的fPut的升幅明显大于豫豆24号。甲基乙二醛-双(鸟嘌呤腙)(MGBG)处理豫豆24,明显抑制了渗透胁迫诱导的fSpd和fSpm的增加,并且加重了渗透胁迫的伤害;外源Spd处理豫豆6号明显促进了渗透胁迫诱导的fSpd和fSpm的增加,并且减缓了渗透胁迫的伤害。统计分析表明:在渗透胁迫条件下,大豆幼苗叶片的fSpd+fSpm/fPut的比值与相对干重增长率(RDWIR)呈显著正相关。渗透胁迫下,豫豆24叶片的AISCC-PAs含量的上升幅度明显大于豫豆6号。菲咯啉处理明显抑制了渗透胁迫所诱导AISCC-PAs的增加,同时也加重了渗透胁迫对幼苗的伤害。渗透胁迫也引起了幼苗叶片中ASCC-PAs含量的上升,但是在两个大豆品种之间的上升幅度没有差异。这些结果表明,渗透胁迫条件下,大豆幼苗叶片的fSpd、fSpm及AISCC-PAs含量的上升有利于增强大豆幼苗的抗胁迫能力。

The changes in content and form of polyamines （PAs） in the leaves of two soybean （ Glycine max L. ） cultivar seedlings differing in drought tolerance were investigated with HPLC under osmotic stress. Yudou No. 24 cv. （drought- No. 6 cv. （drought-sensitive） after treated with polyethylene glycol （PEG） 6,000 for 7 d, while Yudou No. 6 cv. showed a higher increased magnitude in free putrescine （fPut）. Thus Yudou No.24 cv. gave a higher ratio of （fSpd ＋ fSpm） / fPut than Yudou No. 6 cv. in leaves under osmotic stress. Exogenous treatment of seedlings with methylglyoxal-bis （guanylhydrazone） （MGBG）, an S-adenosylmethionine decarboxylase （SAMDC, which catalyzes the Spd and Sam biosynthesis） inhibitor, resulted in a reduction of fSpd and fSpm in leaves and aggravation of PEG-induced injury to Yu- dou No.24 cv. seedlings, while exogenous Spd treatment resulted in an increase in fSpd ＋ fSpm in leaves, furthermore retarded PEG-induced injury in Yudou No. 6 cv. seedling. There was no statistically significant difference between the contents of acid soluble covalently conjugated PAs （ASCC-PAs） in leaves of both cultivars under PEG osmotic stress, suggesting that the level of ASCC-PAs in leaves had no relationship with the osmotic stress tolerance of wheat seedlings. Osmotic stress induced a significant increase in acid insoluble covalently conjugated polyamines （AISCC-PAs） level in AISCC-PAs biosynthesis）, also aggravated PEG-induced injury to Yudou No.24 cv. seedlings, combined with a decrease in AISCC-PAs levels. The results suggested that fSpd, fSpm and PIS-Pas, which strengthened the osmotic stress tolerant capacity of soybean seedlings.