豌豆蚜刺吸胁迫对不同苜蓿品种体内单宁含量及生理活性的影响

通过对甘农5号(G5)、甘农3号(G3)、金皇后(JH)和猎人河(Hu)4种不同抗蚜苜蓿(Medicago sativa L.)品种受豌豆蚜(Acyrthosiphon pisum)胁迫后其叶片内丙二醛(MDA)和单宁含量及防御性酶(超氧化物歧化酶(SOD)和过氧化物酶(POD))活性的动态变化研究,以期明确各项生理指标与抗虫性之间的关系。结果表明:在蚜虫刺吸诱导过程中,抗虫品种(G5)的MDA含量低于低抗品种(G3)和感虫品种(JH),抗虫品种和感虫品种的单宁含量高于低抗品种,感虫品种的SOD和POD活性低于抗虫品种和低抗品种,且所有品种的SOD和POD活性均表现先上升后下降的趋势,而MDA和单宁含量变化无规律。因此,MDA,SOD和POD活性的变化与苜蓿的抗蚜性密切相关,可作为苜蓿抗蚜性生理指标,而单宁与苜蓿抗蚜性的关系有待进一步研究。

Effects of Herbivore Stress by Acyrthosiphon pisum on the Contents of Tannin and Physiological Activity in Different Alfalfa Cultivars

It is necessary to study the relationship between aphid stress and physiological activity in different alfalfa varieties for breeding of resistant alfalfa varieties and sustainable control of aphids.The dynamics of Malondialdehyde(MDA) and Tannin contents and the activities of protective enzymes(Superoxide dismutase(SOD),Peroxidase(POD)) were studied in the leaves of four alfalfa cultivars,Gannong No.5(G5),Gannong No.3(G3),Gloden Empress(JH),and Hunter River(Hu),infested by pea aphid,Acyrthosiphon pisum Harris.Results show that the MDA contents of resistant variety(G5) were lower than that of the susceptible variety(Hu) and low resistant varieties(G3) when their leaves were piercing-sucked by the aphid.The Tannin contents of resistant variety(G5) and the susceptible variety(Hu) were lower than that of the low resistant ones(G3 and JH),While the SOD and POD activities in the susceptible variety(Hu) appeared lower than that of the resistant variety(G5) and low resistant varieties(G3,JH).Throughout the period of aphid attacks,the activities of SOD and POD of all varieties rose initially then declined,whereas the dynamics of MDA and Tannin contents of four alfalfa cultivars were irregular.Therefore,under the aphid stress,the contents of MDA and the activity of SOD,POD in susceptible,low resistant and resistant varieties are closely related to the aphid-resistance of alfalfa.These biochemical markers may be used as physiological indices for aphid-resistance appraisal.However,the relationship between Tannin contents and aphid-resistance of alfalfa requires further research.