保存时间对中华羊茅种子内生真菌活力的影响

以分别保存于2004-2006年的带Epichloë内生真菌(E＋)中华羊茅Festuca sinensis为研究对象,探讨了随着保存时间的延长,内生真菌活力的变化。结果表明,随着保存时间的延长,中华羊茅种子带菌率、幼苗带菌率以及种子的发芽率、发芽指数、根长、苗长均有降低的趋势,同一年种子带菌率均高于幼苗带菌率,2006年带菌率最高,种子为95.80%,幼苗为93.10%;以3个年份的(E＋)中华羊茅草粉浸提液对细交链孢Alternaria alternata、燕麦镰孢Fusarium avenaceum和绿色木霉Trichoderma viride的抑菌活性研究表明,3个年份的带菌草粉浸提液对3种菌的菌落生长和孢子萌发均有一定的抑制作用,但保存时间越长,其抑菌能力越弱,2006年的抑菌率为63.51%,2004年为25.49%,而2006年的抑制产孢能力为69.25%,2004年仅为26.34%。同时,从不同保存年份分离到的内生真菌在相同条件下再培养结果显示,保存时间越长的内生真菌生长越缓慢,产孢能力越弱,2006年的菌落直径为26.4 mm,而2004年仅为17.4 mm。说明随着保存时间的延长,内生真菌活力在逐渐下降,导致自身生长以及促进种子生长,抑制真菌的活性也开始减弱。

Effect of Storage Time on the Activity of Endophytic Fungi of Festuca sinensis

Vigor of Neotyphodium endophytes of Festuca sinensis was studied during seed natural aging condition. The results indicated the seed and seedlings infection rate, seed germination rate and germination index as well as root and shoot length decreased in the process of ageing, and the same year, seed infection rate was higher than seedling. The highest seed infection rate was 95.80%, and seedling was 93.10%. the acetone extracts of endophyte-infected F. sinensis could remarkably enhanced the inhibition on mycelia growth and spore germination of Alternaria alternata, Fusarium avenaceum and Trichoderma viride with the seed deterioration degree, inhibitory rate on mycelia growth was 63.51%, 44.15% and 32.56%, and spore germination was 69.25%, 59.64%, 44.32%, respectively. Fungal endophytes of different storage years were isolated from F. sinensis, which growth rate and sporulation capacity decreased on potato dextrose agar (PDA) after 4 weeks in the same conditions and it became lower and lower with prolonging storing time. In conclusion, vigor of Neotyphodium endophytes decreased with the increased preservation time.