Rostás Michael, Bennett Richard, Hilke Monika
Freie Universität Berlin, Institut für Biologie, Angewandte Zoologie/Okologie der Tiere, Haderslebener Str. 9, D- 12163 Berlin, Germany.
J Chem Ecol. 2002 Dec;28(12):2449-63. doi: 10.1023/a:1021427917603.
Fungal infection of Chinese cabbage leaves by Alternaria brassicae has earlier been shown to have detrimental effects on larval development of the chrysomelid beetle Phaedon cochleariae. Furthermore, adults of this leaf beetle avoid fungus-infected Chinese cabbage leaves for oviposition and feeding. However, herbivory had no impact on fungal growth. In this study, we investigated physiological responses of the host plant to herbivore attack and fungal infection in order to elucidate the mechanisms of the described ecological interactions between the fungus and the herbivore. Changes in primary factors (water, C/N ratio, protein, sucrose) and defense-related plant compounds (glucosinolates, anthocyanins, peroxidase) were measured. Herbivory and fungal infection reduced the sucrose concentration of leaves and increased amounts of indole glucosinolates as well as total anthocyanins. In addition, water content was slightly lower in insect-damaged but not in infected leaves. Higher levels of peroxidase activity resulted exclusively from fungal infection. The C/N ratio and total protein content remained unaffected by either treatment. The implications of the induced plant changes on the herbivore are discussed.
早前研究表明，芸苔链格孢对大白菜叶片的真菌感染会对叶甲科昆虫——菜蓝子的幼虫发育产生不利影响。此外，这种叶甲的成虫会避免在感染真菌的大白菜叶片上产卵和取食。然而，食草行为对真菌生长没有影响。在本研究中，我们调查了寄主植物对食草动物攻击和真菌感染的生理反应，以阐明所述真菌与食草动物之间生态相互作用的机制。我们测量了主要因素（水分、碳氮比、蛋白质、蔗糖）以及与防御相关的植物化合物（芥子油苷、花青素、过氧化物酶）的变化。食草行为和真菌感染降低了叶片中的蔗糖浓度，增加了吲哚芥子油苷以及总花青素的含量。此外，昆虫取食损伤叶片的含水量略低，但感染真菌的叶片含水量未降低。过氧化物酶活性的升高完全是由真菌感染导致的。两种处理均未影响碳氮比和总蛋白含量。本文还讨论了诱导植物变化对食草动物的影响。
