3种镰刀菌对小扁豆生长的影响

Effects of three Fusarium spp. on the growth of lentil in Huining County,Gansu Province

小扁豆(Lens culinaris)是甘肃中部地区普遍栽培的小杂粮之一,既是经济作物,又是轮作倒茬和肥地作物。会宁县种植的小扁豆近年来死亡严重,为查明其死亡原因,开展了田间调查与病原物研究。2012年,当地小扁豆根腐病的发病率为58.4%,死亡率为43.2%,从发病植株的根部分离出的真菌从形态学上鉴定为尖孢镰刀菌(Fusarium oxysporum)、锐顶镰刀菌(F.acuminatum)和木贼镰刀菌(F.equiseti),分离率分别为55%、18%和9%,以ITS为引物扩展真菌的DNA,测序后构建的系统发育树支持以上形态学鉴定结果。接种试验结果显示,此3种镰刀菌均能显著(P<0.05)降低植株的根长和干重,其中尖孢镰刀菌的影响最大,其次为木贼镰刀菌,此2种镰刀菌还显著降低植株的鲜重和株高,但3种镰刀菌均未对出苗率和死亡率产生影响(P>0.05)。在发病田间采集的土壤中播种小扁豆,与灭菌土壤中栽培的植株相比,未灭菌土壤中植株的根长和根干重显著降低。3种镰刀菌对小扁豆菌有致病性,但致病性均不强,干旱可能是导致镰刀菌在田间危害程度加大的主要原因。

Lentil is one of the widely planted crops in the center areas of Gansu Province as economic,rotation and soilfertilized plant. However,death of lentil is very serious in Huining County in recent years. The field investigation,isolation and identification of causal agent were conducted to determine the reasons of plant death. In 2012,incidence of lentil root rot was 58. 4%,and mortality was 43. 2%. Fungi isolated from the roots of diseased plants were morphologically identified as Fusarium oxysporum,F. acuminatum and F. equiseti,which were consistent with the phylogenetic tree based on ITS sequence. Isolation frequency of these fungi was 55%,18% and 9%,respectively. In the inoculation experiment,the root length and root dry weight of host inoculated with all 3 fungi significantly（ P〈0. 05） decreased in which the host with F. oxysporum decreased most and the host with F. equiseti decreased more. The fresh weight and plant height of host inoculated with F. oxysporum and F. equiseti also decreased. However,the emergence and survival rates of host inoculated with all 3 fungi were not affect（ P〉0. 05）. The soils were collected from lentils fields in Huining as plants growth medium. Compared with plants grown in autoclaved soil,root length and root dry weight of plant grown in no-autoclaved soil significantly（ P〈0. 05） decreased. In conclusion,3 Fusarium species were weak pathogenic to lentils. Drought possible was the main reason for these Fusarium species causing serious death on lentils.