壳聚糖处理对两种马铃薯干腐病菌的抑制效果比较

Comparison of inhibition on two pathogens of dry rot in potato tubers by chitosan treatments

由镰刀菌(Fusarium)引起的干腐病是马铃薯块茎采后的重要病害。本文通过体外和体内实验测定了不同浓度壳聚糖处理对马铃薯干腐病菌的抑制效果。结果表明,体外条件下壳聚糖处理能够有效抑制F.sulphureum和F.sambucinum的孢子萌发,不同浓度壳聚糖处理后F.sulphureum的孢子萌发相比对照下降了92%,F.sambucinum的孢子萌发几乎完全被抑制。壳聚糖处理能够有效抑制F.sulphureum和F.sambucinum的菌落直径的扩展,其中以0.25%处理效果最好,比同期对照分别下降7.46%和8.9%,且对F.sambucinum的抑制效果较好。壳聚糖处理可显著降低F.sulphureum和F.sambucinum损伤接种马铃薯块茎切片的病斑直径,0.25%的壳聚糖处理者的病斑直径分别低于对照45.3%和34.5%,更高浓度处理并没有增加抑制效果。由此表明,壳聚糖可通过直接抑菌抑制马铃薯的干腐病。

Dry rot is an important postharvest disease of potato tubers caused by Fusarium.This study investigated the effects of chitosan at different concentrations against F.sulphureum and F.sambucinum of dry rot pathogens in potato tubers in vitro and in vivo.Resuits indicated that chitosan significantly inhibited the spore germination of two pathogens.The rate of spore germination of F.sulphureum was 92% lower than the control, and of F.sambucinum was completely inhibited.Chitosan also inhibited the mycelium growth of two pathogens, the mycelium diameter were 7.46% and 8.9% lower than the control at 0.25% of the optimum treatment concentration.Its inhibition showed more effective to F.sambucinum.Chitosan inhibited the lesion diameter of slices inoculated with F.sulphureum and F.sambucinum, and lesion diameters were 45.3% and 34.5% lower than the control at 0.25% of the optimum treatment concentration. Efficacy was not enhanced when the concentration of chitosan was increased. It is proposed that chitosan treatment could directly inhibit pathogen growth and decrease dry rot of potato tubers by induced resistance.