苹果组培苗形成丛枝菌根的过程

Arbuscular Mycorrhizae Formed Process on the Tissue-Cultured Plantlets of Apple

以苹果N26组培苗为试验材料．以漏斗球囊霉为接种体．进行温室接种试验．经过不同时间取样、染色、压片．观察丛枝菌根的形成过程及其形态结构变化。结果表明：接种2周后就有菌丝侵入，在皮层组织的细胞内开始形成丛枝结构．4周后有胞间泡囊产生．6周后丛枝较密集．8周后有些丛枝开始消解．在皮层细胞间和细胞内形成很多泡囊．10周后开始有抱子产生。12周后孢子数量逐渐增多。丛枝菌根着生率、根内泡囊数和根上菌丝着生率随时间的延长而呈递增趋势。最初以抱子或根外菌丝为侵染体．入侵点在根尖生长点后0.5～1.0cm处的伸长区。菌丝通过入侵点进入到皮层组织细胞后。经过多次分枝形成丛枝状吸器。当丛枝衰老时．在细胞腔内的菌丝顶端形成泡囊。老感染区细胞间的菌丝顶端也可见泡囊形成。丛枝菌根主要分布在中上层10cm的土层内．其菌根的感染率和感染强度随上层加深而减少。

The tissue-cultured plantlets of apple M26 were inoculated with Glomus mosseae in a greenhouse experiment. The formation process of the arbuscular mycorrhizae (AM) and their morphological change were sampled at different time and observed under microscope by staining. The results showed that at first. the spores and hyphae outside the root served as inoculum and infected the 0.5^-1.0 cm zone behind the growth point on the root tip. The hyphae of G. mosseae began to infect and form arbuscules in conices of the host in 2 weeks after inoculations. The vesicae appeared between the host cells in 4 weeks. The arbuscles became closer in 6 weeks and started to disintegrated. but a lot of vesicae occurred in conices in & weeks. The spores formed and gradually increased in 10 weeks. The infection rate of AM. the vesicae number and the hyphae infection rate in root increased with the extension of time. AM fungi (AMF) mainly distributed in the upper and middle level of the soil and the infection rate and seventy of AMF reduced with the increase of the depth of the soil.