干旱胁迫对紫花苜蓿叶片和根系多胺代谢的影响

摘要

采用盆栽试验方法研究了紫花苜蓿(品种:陇东)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)活性的动态变化.结果表明,干旱胁迫下紫花苜蓿叶片和根系中的多胺含量增加,随着胁迫时间的延长,Put、Spd、Spm及ADC、ODC、PAO活性均呈先上升后下降的趋势,且随胁迫程度加重而增大.ADC、ODC活性与Put含量呈极显著正相关,参与了紫花苜蓿Put的合成代谢.PAO活性与Spd、Spm含量变化趋势相似且呈极显著相关关系,叶和根中多胺代谢显著相关,表明多胺代谢与紫花苜蓿抗旱性关系密切.%Changes in the contents of endogenous polyamines (PAs) and the activities of metabolic enzyme in the leaves and roots of alfalfa under drought stress were studied to clarify the theoretical role of polyamine metabolism in alfalfa drought-resistance. The contents of PAs (Putrescine, Spermidine, Spermine) and the activities of ADC, ODC and PAO in the leaves and roots of alfalfa initially increased but then decreased with time. With drought stress intensification, the rising amplitude of PAs content and the activities of ADC and ODC increased. There was a significant positive correlation between Put content and the activities of ADC and ODC in the leaves and roots, suggesting that both ADC and ODC were the major pathways of Put biosynthesis in alfalfa under drought stress. Moreover, it indicated that there was a significant positive correlation not only between PA (Spd and Spm) contents and PAO activity in the leaves and roots of alfalfa but with polyamine metabolism in the leaves and roots as well. There was a close relationship between polyamine metabolism and alfalfa drought-resistance.