稻曲病菌生长及其分生孢子萌发特性

Study on characteristics of the mycelial growth and conidia germination of Ustilaginoidea virens

研究了不同培养基、温度、pH对稻曲病菌生长及其分生孢子萌发的影响.结果表明,PSA适合病菌生长.该菌菌丝生长和分生孢子萌发的温度范围均为15-30℃,最适温度均为28℃;pH 4-11适合其生长和萌发,最适pH均为6.病菌在PSB培养液中培养13 d的菌丝干重最大(16.48 mg.mL-1),培养9 d的分生孢子数量最高(4.19×106个.mL-1).然而,随培养时间的延长,培养液中的菌丝干重、孢子数量和pH明显下降,培养液能抑制水稻种子发芽.在15-33℃和13-23℃自然变温条件下培养48 h分生孢子萌发率分别达81.79%和44.20%,而4℃存放168 h后能使分生孢子在28℃条件下48 h的萌发率下降43.38%,40℃存放6 h后未见分生孢子萌发.水稻品种两优培九、汕优63和甬优6号的孕穗期及灌浆初期的2%稻穗匀浆液对分生孢子萌发有促进作用,培养24 h后分生孢子萌发率均达94%以上,显著高于在PSA、2%蔗糖和2%葡萄糖的固体培养基上的萌发率.

The mycelial growth and conidia germination were tested in different culture media,temperature and pH,respectively.The results showed that PSA（potato sucrose agar） was suitable for pathogen growth.The range of temperature of mycelial growth and conidia germination was 15-30 ℃,with the optimum of 28 ℃.The favorable pH was 4-11,with the optimum of pH 6.There were highest dry weight of mycelia（16.48 mg·mL-1） and number of conidia（4.19×106 conidia·mL-1） after pathogen cultured in liquid culture of PSB（potato sucrose broth） for 13 d and 9 d,respectively.However,with the prolong of culture period,the dry weight of mycelia,number of conidia,and pH obviously decreased in PSB,which exhibited inhibition to germination of rice seeds.The conidia germination rate were 81.79% and 44.20% when exposed to temperature range of 15-33 ℃ and 13-23 ℃ for 48 h under natural condition,respectively,but the conidia germination rate decreased 43.38% during 28 ℃ for 48 h after they exposed to 4 ℃ for 168 h,and no conidia germination was found after they exposed to 40 ℃ for 6 h.The 2% extract of panicle at booting stage and preliminary stage of the grout in rice varieties ＇Liangyoupeijiu＇,＇Shanyou63＇ and ＇Yongyou6＇ could significantly promote conidia germination,the effect was better than PSA,2% sucrose and 2% glucose solid media,with over 94% of germination rate during 24 h.