影响空心莲子草镰刀菌生长发育的几个重要因子分析

Analysis of the Three Key Factors Affecting Growth and Sporulation of Fusarium sp. from Alligatorweed

在原有试验发现空心莲子镰刀菌草生长产孢对光照、通气及淹水与否不敏感的基础上,该研究进一步测定营养培养基、温度和酸碱度因子对空心莲子草镰刀菌生长发育的影响.研究结果表明,这3个因子对此真菌菌落生长、分生孢子产生和萌发都有极显著的作用,所以认为它们是影响真菌生长发育的关键因子.真菌菌落生长和产孢的温度范围为15℃～30℃,在25℃时生长最快而产孢最多;分生孢子萌发的适温范围是20℃～35℃,在30℃时萌发率显著高于其它温度处理.对6种培养基的测定结果显示,真菌在马铃薯葡萄糖培养基(PDA)、胡萝卜培养基(CAA)、空心莲子草根茎煎汁培养基(ARS)和空心莲子草叶片煎汁培养基(ALA)上都能够正常生长、产孢和萌发,而在清水洋菜培养基(WA)上不能生长发育,但是马铃薯蔗糖琼脂(PSA)是该真菌的最佳培养基.菌落生长和产孢的适宜酸碱度范围是pH 4.5～pH 11.0,最适约为pH 7.0,在pH 4.0和pH 12.0时生长和产孢都明显减缓;分生孢子萌发适宜的酸碱度范围为pH 4.0～pH 9.0,在pH 10.0～pH 12.0范围内孢子不能萌发.由此可见,在25℃和pH 7.0条件下使用PSA,是空心莲子草镰刀菌的最佳培养条件.

Fusarium sp. was shown a potential biocongtrol agent against alligatorweed （Alternanthera philoxeroides）. After a preliminary experiment which indicated no significant effects of light, aeration and ,wetness, further investigations were conducted to examine effects of nutrient media, temperature and acidity/alkalinity （pH） on growth and sporulation of this fungus. Six media including potato sucrose agar （PSA）, potato dextrose agar （PDA）, water agar （WA）, carrot agar, alligatorweed root extract agar （ARA） and alligatorweed leaf extract agar （ALA） were tested at 25 ℃ and pH7.0. Very significant differ ences （P〈0.01） in colony growth, conidia production and spore germination were detected between all different nutrient media; the fungus grew and sporulated best on PSA and the poorest on WA. The growth and sporulation of the fungus were normal on other media tested. The temperature and pH tests were then done using PSA plates （for colony suits indicated that the two factors gr ha owth and sporulation） or PSA slides （for spore germination） and red extremely significant effects （P〈0. 001） on the fungus. Fungal colony growth, spore production and germination were normal at 15℃ ～30℃ and pH4.5～11.0 and were the best at about 25℃ and pH7.0. The fungus did not grow and germinate normally at 10℃ and 35℃～40℃, and at pH4.0 and pH 2.0; the germination of fungal conidia was well at pH4.0~pH9.0 but no germina tion was observed when pH values were pH0.0~pH12.0. In conclusion, nutrient media, temperatur,and pH value had striki dium, temperature and conidia germination of t ng pH his impacts on and were thus the key factors affecting, Fusarium sp. The best me value were, respectively, PSA, 25℃ and pH7.0 for growth, sporulation and fungus.