水分胁迫对番茄幼苗叶片和根系中多胺代谢的影响

Effect of water stress on polyamines metabolism in leaves and roots of tomato seedlings

【目的】探讨番茄体内多胺代谢与抗旱性的关系,为植物抗旱性的深入研究提供理论依据。【方法】以番茄幼苗为材料,用不同质量浓度(0(CK),50,75,100 g/L)的聚乙二醇(PEG6000)模拟水分胁迫,研究不同水分胁迫条件下番茄幼苗叶片和根系中多胺代谢的变化。【结果】水分胁迫影响番茄幼苗叶片和根系中的多胺代谢,随胁迫时间的延长,番茄幼苗叶片和根系中游离态腐胺(Put)、亚精胺(Spd)、精胺(Spm)及精氨酸脱羧酶(ADC)、鸟氨酸脱羧酶(ODC)、多胺氧化酶(PAO)活性均呈先上升后下降的趋势,且除PAO外上升幅度随胁迫程度加重而增大。番茄幼苗叶片和根系中ADC、ODC活性与Put含量极显著正相关,水分胁迫下ADC、ODC都参与番茄幼苗Put的合成代谢;PAO活性与Spd、Spm含量变化趋势相似且极显著相关,叶片与根系中的多胺代谢显著相关。【结论】水分胁迫下番茄幼苗中多胺代谢活跃,且不同水分胁迫处理间多胺代谢差异显著,多胺代谢与番茄抗旱性间关系密切。

[Objective] The study was done to evaluate the relationship between polyamines metabolism and the resistance to drought in tomato, and to provide theoretical foundation for further research of plants＇ drought-resistance. [Method] The changes in contents of endogenous polyamine （PAs） and metabolic enzyme activities in leaves and roots of tomato seedlings grown by hydroponic cultivation under different levels of water stress, which were induced by different polyethylene glycol （PEG6000） concentrations as 0（CK）, 50,75 and 100 g/L respectively, were studied. [Result] Polyamines metabolism in leaves and roots of tomato seedlings was affected by water stress. The contents of PAs （Put,Spd,Spm） and activities of ADC,ODC and PAO in leaves and roots of tomato seedlings showed a trend of rise first, then fell with the prolongation of time. With the water stress degree intensifying, the rising amplitude of PAs contents and activities of ADC and ODC increased. [Conclusion] There was a significant positive correlation between Put contents and the activities of ADC and ODC in the leaves and roots,which suggested that both ADC and ODC are the major pathway of Put biosynthesis in tomato seedlings under water stress. Moreover,it was indicated that there was a significant positive correlation between PAs （Spd and Spm） contents and PAO activity in leaves and roots of tomato seedlings, and polyamines metabolism in leaves and roots was correlated evidently. A close relationship between polyamines metabolism and tomato drought-resistance was found.