Abstract

Incomserb, P. (1994)

Effect of Mycorrhyiza on Germination and Seedling Growth Rate of Native Tree Species at Doi Suthep-Pui National Park and Chiang Mai University

This study investigated the effects of vesicular-arbuscular mycorrhiza on germination and growth rate of 5 tree species: Bauhinia purpurrea Linn., Toona ciliata M. Roem, Peltophorum dasyrachis Miq. Kunz, Turpinia pomifera DC. and Melia toosandra Sieb & Zuee.

Two species: M. toosandra and T. pomifera, were selected from Doi Suthep-Pui National Park. B. purpurea, T. ciliata and P. dasyrachis seeds were collected in Chiang Mai University. In the experiment, 3 treatments were set up for each species: i) soil from around the roots of the adult trees was used. ; ii) sterilized soil was prepared and iii) sterile soil was inoculated with the mycorrhizal fungus, Glomus micropus. A pilot study was carried out to determine the condition required to sterilize soil. The most effective sterilization method was 1/2 kg of soil placed in an autoclave at 121oC, 15 pound / inch 2 for 3 hours.

Only three species germinated and survived: B. purpurea, T. ciliata and T. pomifera. Mycorrhiza had no effect on the percent germination rate. But soil sterilization increased germination rate of T. ciliata (p = 0.05). Inoculation of soil with G. microcarpus had no significant effect on any of the parameters measured, except percent root infection of seedlings at the end of the experiment which was significantly increased (p< 0.05). Soil sterilization significantly increased germination of T. ciliata and increased height and growth rate of B. purpurea and T. ciliata. It is likely that sterilisatioin had a significant effect by eradicating pathogens from the soil.