列当寄生对不同品种向日葵幼苗生长及抗氧化酶活性的影响

Effect of Orobanche cumana Parasitization on Growth and Antioxidant Enzymes Activity of Different Helianthus annuus Varieties in Seedling Stage

采用连作重茬含向日葵列当的土壤,进行不同列当抗性向日葵品种苗期盆栽试验,调查播种后第30、50和70天向日葵幼苗根系列当的寄生率、幼苗地上部和地下部干物质量及株高,并测定其叶片丙二醛(MDA)、苯丙氨酸解氨酶(PAL)、超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性。结果表明:不同向日葵品种苗期对列当抗性明显不同,其中油葵品种‘T012244’和‘MGS’对向日葵列当寄生免疫,‘S31’和‘白杂9号’为高抗,而‘星火大白边’和‘白杂6号’为敏感。列当寄生后明显抑制敏感品种向日葵幼苗生长,而对免疫品种和高抗品种的影响较小。列当寄生后的敏感性品种‘星火大白边’幼苗叶片MDA含量迅速上升,PAL活性也大幅度增加,列当对幼苗生长伤害加重;而苗期免疫品种"T012244"和高抗品种"S31"MDA含量下降,PAL活性则变化不大。随接种时间延长,不同抗性向日葵品种苗期SOD、POD和CAT活性均呈现先升高后降低的变化趋势,且免疫品种的保护酶活性变化幅度大于敏感品种,说明列当寄生对敏感向日葵品种造成了逆境胁迫,诱导其幼苗叶片保护酶系统产生防御响应。

We investigated the parasitism rate,dry weight of shoot and root,plant height of different Helianthus annuus varieties in seedling stage,measured the content of malondialdehyde （MDA） and the activities of enzyme PAL,SOD,POD and CAT in leaves after sowing 30,50 and 70 days,respectively.The seeds were sown in plastic pots and the soil was collected from continuous H.annuus cropping yield where the Orobanche cumana infection was severe.The results indicated that different H.annuus varieties in seedling stage exhibited obviously different resistance to O.cumana.Oil H.annuus varieties ‘T012244’ and ‘MGS’ were immune to O.cumana in seedling stage,‘S31’ and ‘Baiza 9’ showed a strong resistance to O.cumana.However,‘Xinghuodabaibian’ and ‘Baiza 6’ were sensitive to O.cumana in their seedling stage.Parasitization of O.cumana could restrain the growth of sensitive H.annuus varieties but hardly impact the growth of resistant H.annuus varieties.After parasitization of O.cumana,the MDA content and the PAL activity in leaves of ‘Xinghuodabaibian’ seedling increased significantly,which indicated an aggravated damage on H.annuus seedings.However,the MDA content in leaves of varieties‘T012244’and‘S31’ decreased and the activity of PAL did not significantly changed.The enzyme activities of SOD,POD and CAT in different H.annuus varieties all decreased after an initial increase.The change ranges of protective enzyme activities in immune varieties are bigger than that in sensitive varieties.The parasitization of O.cumana put the sensitive H.annuus varieties under environmental stress in seedling stage,defense reactions based on protective enzyme system were induced in seedling leaves.