Abstract：
Despite significant research on early and late leaf spot diseases of peanut, in vitro study of the respective causal agents, Passalora arachidicola and Nothopassalora personata, has been limited due to cultural challenges that make growth of these fungi difficult to quantify with traditional methods. Studies were conducted to evaluate the practicality of image analysis to assess radial growth and tissue volume by correlating these assessments to dry mass. Image analysis was also used to estimate radial growth rates for these fungi over time. Tissue area and volume were significantly correlated to dry mass for P. arachidicola in two separate experiments, and for N. personata when medium had been removed from tissues prior to dry mass assessments. Tissue area densities were the same for P. arachidicola and Pseudocercospora smilacicola, evaluated as a nonstromatal cercosporoid comparison, whereas tissue volume densities were greater for P. archidicola and N. personata than P. smilacicola. A quadratic relationship was observed between radial growth and incubation time for all isolates evaluated. Growth rates of P. arachidicola isolates were 2 to 4 times faster than N. personata during the first week of incubation and slowed over time. Growth rates of NP18R, a phenotype variant of N. personata, increased after neighboring colonies met and was nearly 2.5 times faster than the fastest rates observed for P. arachidicola. These experiments demonstrate that when fungal tissues are observable, image analysis is a useful assessment tool for P. arachidicola and N. personata. Care should be taken to monitor fungal phenotypic changes in these species because phenotype degeneration can affect growth rates.
摘要：
尽管对花生早期和晚期叶斑病进行了大量研究，各自病原体的体外研究，帕萨洛拉·阿奇迪科拉和Nothopassalora人格，由于文化挑战使这些真菌的生长难以用传统方法量化，因此受到限制。进行研究以通过将这些评估与干重相关联来评估图像分析以评估径向生长和组织体积的实用性。图像分析还用于估计这些真菌随时间的径向生长速率。在两个单独的实验中，花生双歧杆菌的组织面积和体积与干质量显着相关。以及在干质量评估之前从组织中去除培养基时的属性菌。arachindicola和sempseocerosporasilacicola的组织面积密度相同，评估为非基质类cercosporoid比较，而古生假单胞菌和N.personata的组织体积密度大于smiracicola。在所有评估的分离株的径向生长和孵育时间之间观察到二次关系。在孵育的第一周期间，花生双歧杆菌分离株的生长速率比N.personata快2至4倍，并且随着时间的推移而减慢。NP18R的增长率，N.personata的表型变体，在邻近的殖民地相遇后增加，比观察到的最快速度快2.5倍。这些实验表明，当真菌组织是可观察的，图像分析是一种有用的评估工具。应注意监测这些物种的真菌表型变化，因为表型退化会影响生长速率。
