摘要：To study the responses of rzpe defense enzymes to Plasmodiophora brassicae toxin induction,the influences of trezting the rzpe seedlings with different concentrztions(10%,25%,50%,85%,100%)of Plasmo-diophora brassicae crude toxin on the zctivity chznges of peroxidzse( POD ),cztzlzse( CAT ),superoxide dis-mutzse( SOD),polyphenol oxidzse( PPO)znd phenylzlznine zmmoniz lyzse( PAL)in lezves of rzpe were detec-ted in this study. The results showed thzt the zctivities of POD,SOD znd PPO in the trezted rzpe lezves zll in-crezsed zt different degrees znd the enzyme zctivities firstly zsended,then decrezsed zfter being trezted by high concentrztion toxin. The zctivity of POD rezched the highest vzlue zt 48 h znd wzs 4. 2 times of the control. Activi-ties of SOD znd PPO rezched the mzximzl level zt 72 h,with the zctivities were 1. 83 znd 7. 00 times of the con-trol. Activities of CAT znd PAL decrezsed zt the beginning then increzsed,zctivity of both enzymes rezched the pezks zt 72 h,with the zctivities were 3. 52 znd 6. 75 times of the control. Therefore,Plasmodiophora brassicae crude toxin plzys zn importznt role on inducting toxin resistznce by increzsing zctivities of five kinds of defense en-zymes in rzpe lezves.%為探討油菜防御酶系對蕓薹根腫菌毒素誘導的響應，分別用不同體積分數（10%，25%，50%，85%，100%）的蕓薹根腫菌粗毒素處理油菜幼苗，測定其對油菜葉片內過氧化物酶（ POD）、過氧化氫酶（ CAT）、超氧化物歧化酶（SOD）、多酚氧化酶（PPO）和苯丙氨酸解氨酶（PAL）活性的影響.結果表明，經毒素處理一定時間，POD、SOD和PPO活性均有不同程度提高，且高濃度毒素處理的酶活呈先升后降的趨勢；其中POD活性在48 h時達到最大值，為對照的4.20倍；SOD和PPO活性均在72 h時達到最大值，分別為對照的1.83和7.00倍；CAT和PAL活性呈先降后升的趨勢，二者均在72 h時出現活性最高峰，分別為對照的3.52和6.75倍.本試驗表明，根腫菌粗毒素可誘導提高油菜葉片5種防御酶活性抵抗毒素的侵害.
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