对羟基苯甲酸胁迫下间作对蚕豆枯萎病发生和根系抗氧化酶活性的影响

连作障碍是限制蚕豆生产的重要因素,利用植物间化感作用的间作栽培模式是解决连作障碍的有效手段。为了探究对羟基苯甲酸胁迫下蚕豆与小麦间作对蚕豆生长和枯萎病发生的影响及其生理响应,通过盆栽土培试验研究不同浓度C0(0 mmol·L~(-1))、C1(0.36 mmol·L~(-1))、C2(0.72 mmol·L~(-1))和C3(1.45 mmol·L~(-1))]对羟基苯甲酸处理下,小麦与蚕豆间作蚕豆生长、枯萎病发生、抗氧化酶(POD和CAT)活性和膜质过氧化程度(MDA含量)的影响,从生理抗性角度探讨小麦与蚕豆间作缓解对羟基苯甲酸自毒效应的机制。结果表明,随着对羟基苯甲酸处理浓度提高,蚕豆生物量呈先增加后降低的趋势;C1和C2提高了蚕豆根系POD和CAT活性,降低了镰刀菌的数量,减轻了枯萎病的发生;C3降低了根系POD和CAT活性,增加了镰刀菌的数量,促进了枯萎病发生;随对羟基苯甲酸处理浓度增加,MDA含量显著增加,证实了对羟基苯甲酸是导致蚕豆连作障碍形成的主要自毒物质。与单作相比,对羟基苯甲酸胁迫下间作显著提高了根系POD活性(4.17%~22.22%)和CAT活性(10.53%~11.11%),显著降低了MDA含量(11.20%~52.80%);镰刀菌数量降低4.63%~23.65%,病情指数降低13.33%~50.00%,蚕豆干重显著增加15.73%~20.63%。综上,小麦与蚕豆间作通过提高蚕豆的生理抗性而减轻对羟基苯甲酸引起的枯萎病危害,促进蚕豆生长,是缓解对羟基苯甲酸自毒效应的有效措施。本研究结果为间作缓解连作障碍中的自毒效应提供了理论论据。

Effect of Intercropping on Fusarium Wilt of Faba Bean and Antioxidant Enzyme Activity of Roots Under the p-hydroxybenzoic Acid Stress

Faba bean is susceptible to wilt disease under continuous monocropping management.Faba bean and wheat intercropping was effective measure to alleviate faba bean wilt disease in continuous management soil.To investigate the effects of p-hydroxybenzoic acid on faba bean seedling growth and Fusarium wilt occurrence,and to explore the alleviation mechanism of wheat and faba bean intercropping on faba bean autotoxicity,A plot experiment of faba bean and wheat intercropping with p-hydroxybenzoic acid application was conducted in the greenhouse of Yunnan Agricultural University.Four p-hydroxybenzoic acid rates were set,which were C0 (0.00 mmol· L-1) 、C1 (0.36 mmol· L-1) 、C2 (0.72 mmol· L-1) and C3 (1.45 mmol· L-1)],with two planting patterns,faba bean monocropping and faba bean and wheat intercropping.The growth,enzymes activities (peroxidase,POD and catalase,CAT),peroxidation (MDA) content as well as occurrence of faba bean Fusarium wilt were investigated.The results showed that in comparison with C0,the biomass of monocropped faba bean increased first and then decreased with increasing ofp-hydroxylbenzoic acid application rates.The activities of POD and CAT in monocropped faba bean roots were increased with C1 and C2 treatment but decreased with C3 treatment,while the amount of Fusarium oxysporum and the occurrence of Fusarium wilt were decreased with C1 and C2 treatment but increased with C3 treatment,which promoted the occurrence of Fusarium wilt.Malondialdehyde (MDA) content in faba bean roots were significantly increased with increasing of p-hydroxybenzoic acid rates.Thus it was concluded that p-hydroxybenzoic acid was one of the main autotoxins in faba bean continuous cropping.Comparison with monocropped faba bean,Peroxidase (POD) and catalase (CAT) activities in intercropped faba bean roots were increased by 4.17％ to 22.22％ and 0.53％ to 11.11％.MDA content and disease index of intercropped faba bean were decreased by 11.20％ to 52.80％ and 13.33％ to 50.00％,the dry weights were increased by 15.73％ to 20.63％.In summary,faba bean and wheat intercropping significantly improved the activities of the antioxidant enzymes in faba bean,and decreased the degree of membrane lipid peroxidation,resulting in a increase in the resistance of faba bean to Fusarium oxysporum,faba bean growth was promoted.Thus,Faba bean and wheat intercropping was an effective method to alleviate faba bean autotoxicity caused by p-hydroxybenzoic acid.The results also provided a theoretical basis for intercropping to control soil-borne diseases caused by continuous crop cultivation.