丛枝菌根真菌对植物根尖分生区和根冠细胞的侵染*

一般说来，从枝菌根（ＡＭ）真菌大多数是从植物根系根毛区（成熟区）侵入和扩展的，在显微镜下往往看不到根尖分生区和根冠表皮细胞被ＡＭ真菌侵染的特征。这就很容易给人们造成一种假象，似乎ＡＭ真菌不能侵染根尖分生区和根冠表皮细胞，即它们对ＡＭ真菌是免疫的。然而笔者多次于显微镜下看到ＡＭ真菌侵染根尖分生区和根冠表皮细胞，并形成典型的泡囊、丛枝、菌丝等结构。这一现象导致作者在温室盆栽和大田条件下研究了玫瑰红巨孢囊霉（ Ｇｉｇａｓｐｏｒａ　ｒｏｓｅａ Ｎｉｃｏｌ　＆ Ｓｃｈｅｎｃｋ）、珠状巨孢囊霉（Ｇｉｇａｓｐｏｒａ　ｍａｒｇａｒｉｔａ　Ｂｅｃｋｅｒ　＆　Ｈａｌｌ）、根内球囊霉（Ｇｌｏｍｕｓ　ｏｍｔｒａｒａｄｉｃｅｓ　ｓｃｈｅｎｃｋ　＆　Ｓｍｉｔｈ、摩西球囊霉（Ｇｌｏｍｕｓ ｍｏｓｓｅａｅ （Ｎｉｃｏｌ　＆ Ｇｅｒｄ．） Ｇｅｒｄｅｍａｎｎ　＆ Ｔｒａｐｐｅ）、地表球囊霉（ Ｇｌｏｍｕｓ ｖｅｒｓｉｆｏｒｍｅ（ Ｋａｒｓｔｅｎ）Ｂｅｒｃｈ）和弯丝硬囊霉（ Ｓｃｌｅｒｏｃｙｓｔｉｓ　ｓｉｎｕｏｓａ　Ｇｅｒｄｅｍａｎｎ　＆ Ｂａｋｈｉ）对棉花（Ｇｏｓｓｙｐｉｕｍ　ｈｉｒｓｕｔｕｍ　Ｌ．）、烟草（Ｎｉｃｏｔｉａｎａ　 ｔａｂａｃｕｍ Ｌ．）和白

COLONIZATION OF AM FUNGI IN MERISTEMATIC ZONE AND CAP CELLS OF PLANT ROOTS

Colonization characteristics of arbuscular mycorrhizal(AM) ac Gigaspora rosea Nicol & Schenck, Gigaspora margarita Becker & Hall, Glomus intraradices Schenck & Smith, Glomus mosseae (Nicol & Gerd.) Gerdemann & Trappe, Glomus versiforme (Karsten ) Berch and Sclerocystis sinuasa Gerdemann & Bakhi in root tips of cotton (Gossypium hirsutum L.), tobacco (Nicotiana tabacum L.) and white clover (Trifolium repens L. ) grown in pots were investigated. Roots of soybean (Glycine max (Linn.) Merr.), corn (Zea mays L.) and cotton grown in natal field were also sampled and Observed. The result showed that conical cells of the root meristematic zone and cap cells of cotton, tobacco and white clover were colonized by the AM fungi. Typical entry points, vesicles, hyphae and arbuscule were formed in the cap cells and conical cells of meristematic zones of roots. The colonization percentage of the meristematic zone and cap cells colonized by AM fungi on the second or third oder branch roots were higher than those on the first order branch roots and tap roots. White clover inoculated with G. mosseae had the highest frequency of colonization on root tips, while tobacco inoculated with Gigaspora margarita showed the lowest frequency. In nature field the conical cells of root meristematic zone and cap cells of soybean, corn and cotton were also colonized by AM fungi, but the incidence of root tip colonized was much lower. It was concluded that the meristematic zone and Cap cells of plant roots were able to be colonized by AM fungi.