Martínez J A, Valdés R, Bañón S
Universidad Politécnica de Cartagena, Escuela Técnica Superior de Ingeniería Agronómica, Dept. Producción Vegetal, Paseo Alfonso XIII, 48, ES-30203 Cartagena, Spain.
Commun Agric Appl Biol Sci. 2010;75(4):709-19.
The growth of different isolates of Botrytis cinerea, collected from potted plants affected by Botrytis blight in southern Spain during recent years, was studied. These isolates, which show wide phenotypic differences when grown in vitro, are differentially affected by growth temperature, gibberellic acid, and paclobutrazol--an efficient plant growth retardant used widely in nursery potted plants to reduce plant size, favouring compactness, a more intense green foliage and increased stress tolerance to maintain quality prior to sale. In addition, paclobutrazol may have a fungicidal effect since it belongs to the triazole chemical group. However, paclobutrazol is only used as a plant growth retardant in Spain. In this work, we evaluate the effect of paclobutrazol dose (0, 0.05, 0.25, 1.25, and 6.25 mg/plate) on the growth of a collection of different B. cinerea isolates obtained from the following potted plants: Cyclamen persicum, Hydrangea macrophylla, Lantana camara and Lonicera japonica. Mycelial growth curves and growth rates assessed from difference in colony areas during the linear phase, conidiation (measured as time of appearance), conidial length (microm), and sclerotia production (number/plate) were evaluated in the isolates, which were grown at 26 degrees C on Petri dishes containing potato dextrose agar for up to 36 days. Mycelial growth curves fitted a typical kinetic equation of fungus grown on solid media. The B. cinerea isolates showed a high degree of variability in their growth kinetics, depending on the isolate and paclobutrazol dose. This triazole delayed mycelial growth during the linear phase in an isolate-dependent manner, and isolates from C. persicum and L. japonica were more affected by paclobutrazol than H. macrophylla. On the other hand, 0.25 mg of paclobutrazol was the critical dose to significantly reduce the growth rate in all isolates. 6.25 mg paclobutrazol inhibited conidiation in isolates from C. persicum, and reduced the conidial length in isolates from H. macrophylla and L. camara. The sclerotia production process was blocked at paclobutrazol doses higher than 1.25 mg, while no sclerotia were produced in isolates from C. persicum and L. japonica with 0.25 mg. H. macrophylla was the isolate in which sclerotia production was most influenced by paclobutrazol. It was concluded that the exact effect of paclobutrazol on B. cinerea growth depends on the isolate, and new strategies should be considered for evaluating its use as retardant and fungicide.
对近年来从西班牙南部受灰霉病影响的盆栽植物中分离得到的不同灰葡萄孢菌菌株的生长情况进行了研究。这些菌株在体外培养时表现出广泛的表型差异，它们受生长温度、赤霉素和多效唑（一种在苗圃盆栽植物中广泛使用的高效植物生长延缓剂，用于减小植株大小，促进紧凑性，使叶片颜色更浓绿，并提高胁迫耐受性以在销售前保持品质）的影响各不相同。此外，多效唑可能具有杀菌作用，因为它属于三唑化学基团。然而，在西班牙多效唑仅用作植物生长延缓剂。在这项研究中，我们评估了多效唑剂量（0、0.05、0.25、1.25和6.25毫克/平板）对从以下盆栽植物中获得的不同灰葡萄孢菌菌株集合生长的影响：仙客来、大叶绣球、马缨丹和日本忍冬。在含有马铃薯葡萄糖琼脂的培养皿中于26℃培养分离菌株长达36天，评估了菌丝生长曲线以及根据线性阶段菌落面积差异评估的生长速率、产孢（以出现时间衡量）、分生孢子长度（微米）和菌核产生（数量/平板）。菌丝生长曲线符合真菌在固体培养基上生长的典型动力学方程。灰葡萄孢菌菌株的生长动力学表现出高度变异性，这取决于菌株和多效唑剂量。这种三唑类化合物以菌株依赖的方式在线性阶段延迟菌丝生长，来自仙客来和日本忍冬的菌株比大叶绣球的菌株受多效唑的影响更大。另一方面，0.25毫克多效唑是显著降低所有菌株生长速率的临界剂量。6.25毫克多效唑抑制了来自仙客来的菌株的产孢，并减小了来自大叶绣球和马缨丹的菌株的分生孢子长度。当多效唑剂量高于1.25毫克时，菌核产生过程受阻，而在含有0.25毫克多效唑的情况下，来自仙客来和日本忍冬的菌株未产生菌核。大叶绣球是菌核产生受多效唑影响最大的菌株。得出的结论是，多效唑对灰葡萄孢菌生长的确切影响取决于菌株，应考虑采用新策略来评估其作为生长延缓剂和杀菌剂的用途。
