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本文对来自红海榄(Rhizophora stylosa)赤斑病同一病斑上获得的2个菌株PⅠ-1和PⅡ-3进行了鉴定和生物学特性研究。结果表明,PⅡ-3菌株的致病力比PⅠ-1的稍强;2个菌株均具有一定的寄主专化性。经形态特征观察与rDNA-ITS序列分析,2个菌株均鉴定为异色拟盘多毛孢(Pestalotiopsis versicolor)。生物学特性测定结果表明,温度、pH值和光照对2个菌株菌丝生长及孢子萌发的影响差异不大,生长温度均为10～32℃(最适25℃),pH值为3.0～10.9(最适4.0);孢子萌发温度均为10～35℃(最适25～28℃),pH值为2.5～8.0(最适3.0);黑暗条件有利于2个菌株菌丝生长和孢子萌发。但2个菌株的产孢特性存在明显差异,其中PⅠ-1产孢的最适温度为28℃而PⅡ-3为20℃;PⅠ-1产孢的最适pH值为5.1而PⅡ-3为9.0;PⅠ-1产孢对光照不敏感,而PⅡ-3在黑暗条件下几乎不产孢。另外,在相似条件下,PⅠ-1产孢量比PⅡ-3大,而PⅡ-3菌丝生长速度比PⅠ-1快,孢子萌发率也比PⅠ-1高。由此可见,2个菌株PⅠ-1和PⅡ-3虽属于同一个种,但某些生物学特性存在一定的差异。
In this paper, two strains PⅠ-1 and PⅡ-3 from the same lesion of Rhizophora stylosa were identified and their biological characteristics were studied. The results showed that the pathogenicity of PⅡ-3 strain was slightly stronger than that of PⅠ-1. Both of the two strains had some host specificity. Morphological observation and rDNA-ITS sequence analysis showed that the two strains were identified as Pestalotiopsis versicolor. The results of biological evaluation showed that the effects of temperature, pH value and light on the mycelial growth and spore germination of the two strains were not significantly different. The growth temperature was 10 ~ 32 ℃ (optimum 25 ℃) and the pH value was 3.0 ~ 10.9 (Optimum 4.0). The spore germination temperature was 10-35 ℃ (optimum 25-28 ℃) and the pH value was 2.5-8.0 (optimum 3.0). The darkness was favorable to mycelial growth and spore germination of the two strains. However, there were significant differences in the sporulation characteristics of the two strains, in which the optimal temperature for sporulation of PⅠ-1 was 28 ℃ and that of PⅡ-3 was 20 ℃. The optimum pH for sporulation of PⅠ-1 was 5.1 and PⅡ-3 was 9.0; PⅠ-1 sporulation is insensitive to light, while PⅡ-3 hardly sporulates in dark conditions. In addition, under similar conditions, the sporulation of PⅠ-1 was larger than that of PⅡ-3, while the growth of PⅡ-3 mycelium was faster than that of PⅠ-1, and the spore germination rate was also higher than that of PⅠ-1. Thus, two strains PⅠ-1 and PⅡ-3 belong to the same species, but some biological characteristics are different.