Department of Plant Medicine, College of Life Science and Natural Resources, Sunchon National University, Suncheon 540-950, Korea.
Department of Environment Education, College of Education, Sunchon National University, Suncheon 540-950, Korea.
Plant Pathol J. 2013 Dec;29(4):440-5. doi: 10.5423/PPJ.NT.07.2013.0073.
Balloon flower (Platycodon grandiflorum) is a kind of mountain herbs whose roots have restorative properties and the cultivating acreage of balloon flower has been steadily increasing in Korea. More frequent rain and high amount of rainfalls as a result of climate changes predisposed balloon flower to the outbreaks of root rot at high-density cultivation area in recent years. Root crowns were usually discolored into brown to blackish brown at first and the infected plants showed slight wilting symptom at early infection stage. Severely infected roots were entirely rotted and whole plants eventually died at late infection stage. The overall disease severities of root rot of balloon flower were quite variable according to the surveyed fields in Jeonnam, Gyeongnam and Jeju Provinces, which ranged from 0.1% to 40%. The root rot occurred more severely at the paddy or clay soils than the sandy soils and their severities were much higher at lowland than upland in the same localty. The disease increased with aging of the balloon flower. The causal fungi were identified as Fusarium solani and F. oxysporum on the basis of their mycological characteristics. The optimum temperature ranges of their mycelial growths was found to be 24°C. The pathogenic characters of F. solani and F. oxysporum treated by artificial wounding inoculation on healthy roots of balloon flower revealed that F. solani was more virulent than F. oxysporum. This study identified the causal agents of root rot of balloon flower as Fusarium solani and F. oxysporum, probably for the first time.
桔梗是一种山草药，其根具有恢复特性，在韩国，桔梗的种植面积一直在稳步增加。由于气候变化导致降雨更加频繁且降雨量增加，近年来，在高密度种植区，桔梗容易发生根腐病。根冠最初通常会变成棕色到黑褐色，感染初期，受感染的植物会出现轻微萎蔫症状。严重感染的根全部腐烂，晚期感染时整株植物最终死亡。根据在全罗南道、全罗北道和济州道调查的结果，桔梗根腐病的总体严重程度差异很大，范围从 0.1%到 40%不等。在稻田或粘土地中，根腐病比在沙质土壤中更为严重，在同一地区，低地的严重程度比高地高。该病随着桔梗的老化而增加。根据其真菌学特征，将引起该病的病原菌鉴定为茄腐镰孢菌和尖孢镰孢菌。发现它们菌丝生长的最适温度范围为 24°C。通过对健康的桔梗根进行人工创伤接种，研究了茄腐镰孢菌和尖孢镰孢菌的致病性特征，结果表明茄腐镰孢菌比尖孢镰孢菌的毒性更强。本研究首次确定了桔梗根腐病的病原菌为茄腐镰孢菌和尖孢镰孢菌。
