棉花枯萎病菌在棉株体内外产生孢子的类型

棉花枯萎病是一种维管束病害,此病菌在导管中产生大量小分生孢子,小分生孢子在茎中部及子叶节产生较多,其次主根及下胚轴,病子叶柄与生长点较少。棉株随着病情的加重,病导管中孢子数量随之减少。病棉株体表可产生很大数量大分生孢子,并由大分生孢子某些细胞形成厚垣孢子。用 PDA 或选择性培养基培养能产生小分生孢子、厚垣孢子,或数量有限的大分生孢子。体内外部较易产生小分生孢子,而且数量也大。而大分生孢子则需求特定的营养及生态条件才能产生。

Types of spores of(Fusarium oxysporum f.vasinfectum)from infected cotton plants

The Fusarium wilt is a vascular disease of cotton.A large number of microconidia were formed in the vessels.The quantities of microconidia formed in the stem and cotyledon nodes were more than those in the main roots and hypocolyls,while a few microconidia were formed in the growing points and petioles of cotyledons.There were many macroconidia formed on the surface of the infected cotton plants and certain cells of the macroconidia are able to form chlamydospores were observed.The pathogen might produce microconidia,chlamydospores and a few macroconidia when cultured on the PDA selective medium.It necessatates specified nutrients and ecological conditions to produce macroconidia.The microconidia which can be formed both in the vessels and on the surface of infected plants,often caused more serious damage to cotton plants owing to the quantity and higher adoptability of the microconidia.