菌根真菌在墨兰和建兰根中的感染特征及生理特性

Infection Characteristics and Physiological Features of Mycorrhizal Fungi in Roots of Cymbidium sinense and C.ensifolium

从产于粤北山区的野生建兰报中分离出4株内生真菌，并对这些真菌在兰根上的感染特征及生理学特性进行了研究。结果表明，菌根真菌多数浸染植株根段离很尖3～18cm的根毛区，而根尖和新长出的根则很少被感染；几乎所有的老根都受过真菌的感染。真菌菌丝从兰报表皮侵入，通过表皮层进入皮层薄壁细胞内部形成菌丝团，而在表皮层并不进入细胞内，也不形成菌丝团。真菌感染极状整后第9天，皮层细胞内的菌丝团开始消解。所分离的菌株能利用大部分简单的有机碳源和氮源，能在营养成分不明确的天然介质中生长良好，但对硝酸盐的利用较差。

Four endophytic fungi (unidetified) have been isolated from the roots of Cymbidium ensifolium growing in the mountain area of northern Guangdong province. The characteristic of mycorrhizal infection,general morphology and physiology of these isolates were investigated. The results showed that fungi hyphae were frequently present in root hairs sections that were 3～18 cm from root tip. CorticaI infection was rarely seen in root tip and y0ung roots. Almost all old roots have been invaded by mycorrhizal fungi. Fungi hyphae invaded root epidermis into cortical cells and formed pelotons there, but peloton were not seen in epidermal cells. The pelotons in cortical cell of Cymbidium sinense and C. ensifolium rhizomes began to digest after 9 days of infection. These isolates could utilize most of simple carbohydrate and nitrogen source except for nitrate.