Stimulatory effect of peat on spore germination and hyphal growth of arbuscular mycorrhizal fungus Gigaspora margarita

Abstract

The effects of peat extract solutions on spore germination and hyphal growth of the arbuscular mycorrhizal fungus Gigaspora margarita Becker & Hall were investigated. Spores were incubated in extract solutions of peat from China and peat moss from Canada, which were prepared at a weight ratio of 1:10, 1:20, 1:30, 1:50 and 1:100 for each substrate according to the weight ratio of water. Compared with peat and peat moss solutions, solutions of KH₂PO₄ and (NH₄)₂SO₄ at various concentrations were used as media to investigate the effect of phosphorus (P) and nitrogen (N). Spores in the peat solutions showed the highest values for germination percentage, hyphal length and number of auxiliary cells, and these values were significantly higher than the values recorded for the other treatments. In contrast, in the peat moss extract solutions, which had a lower content of N and higher content of P than the peat solutions, the germination and hyphal growth of spores decreased. Spore growth was promoted with increased concentrations of the N solutions. However, P solutions exerted an inhibitory effect on spore germination and hyphal growth. Peat solutions showed a high N content and low P content, which might be related to the promotion of spore growth.

Key words:

• arbuscular mycorrhizal fungus
• Gigaspora margarita
• hyphal growth
• peat
• spore germination

ACKNOWLEDGMENTS

We thank Dr Takahiro Tateishi, Iwate University, for valuable comments on the study. We also thank Mr Kimio Nakamura and Takumi Mitsuno for their assistance with the work and for helpful suggestions on the study.