花生不同品种叶片类黄酮含量和相关合成酶活性对PEG胁迫的响应

以花生品种花17、农大818、丰花5号和山花11号为试材，聚乙二醇(PEG)室内砂培法模拟干旱胁迫，研究20%PEG胁迫下花生幼苗叶片中类黄酮含量及相关合成酶活性的变化。20% PEG开始处理后，随胁迫时间延长，幼苗叶中类黄酮含量逐步上升，在胁迫9h达到高峰，之后逐步下降至对照水平，农大818、丰花5号和山花11号均在处理后72h降至对照水平，花17在36h降至对照水平。PEG开始处理后苯丙氨酸解氨酶（PAL）、查尔酮合成酶（CHS）、查尔酮异构酶（CHI）酶活性均逐渐提高，6h后CHS、CHI酶活性达到高峰，9h后PAL酶活性达到高峰，之后下降，4个品种趋势一致。分析表明PEG处理后山花11号和丰花5号的合成酶具有较高的活性和积累速率是其类黄酮快速大量合成的原因，而农大818 CHS酶活性和PAL酶活性提高速率较低限制了其类黄酮的积累，3种酶的活性和积累速率均较低导致花17叶中类黄酮合成少，含量提高慢。相关分析表明PEG胁迫下PAL、CHS、CHI共同调控类黄酮的代谢，胁迫引起PAL、CHS、CHI酶活性改变是类黄酮含量变化的原因。

Response of flavonoids and related enzymes activity in peanut leaves to PEG stress

Abstract: A method based on sand culture and 20% polyethylene glycol-6000 (PEG 6000) was developed to study the dynamic variation on flavonoids and related enzymes activity in leaves of four peanut varieties (Hua 17, Nongda 818, Fenghua 5, Shanhua 11) seedling with simulate water stress. Results showed that the contents of flavonoids in all varieties seedling leaves decreased initially and increased subsequently，and peaked after 9h under 20% PEG stress, Nongda 818 with Fenghua 5 and Shanhua 11 decreased to control levels at 72h after the treatment, hua17 was about 36h. The activities enzymes of PAL with CHS and CHI gradually increased after PEG stress, CHS and CHI activities peaked at 6h, PAL activity peaked at 9h, then activities declined. These 4 peanut varieties had the same trend. Analysis showed that the reasons of quick synthesis in large quantity for flavonoids of Shanhua 11 and Fenghua 5 for were their higher CHS activity and accumulation rate. PAL of Nongda 818 had lower activity and accumulation rate which limited accumulation of flavonoids. The lower activities and accumulation rates of these 3 enzymes on Hua 17 resulted slow synthesis and small quantity of flavonoids. The correlation analysis indicated that peanut flavonoids was regulated by the combined effect of PAL, CHS and CHI, and the variances of flavonoid contents were a result of changes of these enzymes’ activities under PEG stress.