DETERMINATION OF INFECTION ACTIVITY OF VA MYCORRHIZAE INFECTION AGENT

PROBLEM TO BE SOLVED: To easily and quickly determine the infection activity of a VA mycorrhizae infection agent for infecting a plant with VA mycorrhizae effective for promoting the growth of plants and imparting the plants with blight resistance and dry resistance by measuring the activity of an enzyme in a VA mycorrhizae infection source. SOLUTION: Spores of a VA mycorrhizae [e.g. Gigaspora albida] are recovered from a VA mycorrhizae infection agent, various numbers of the recovered spores are collected and crushed in a 0.1M tris-HCl buffer solution (pH 8.0) with a homogenizer and the crushed product is subjected to centrifugal separation to obtain supernatant liquid. The liquid is used as a crude enzyme liquid, the enzymatic activities of an enzyme participating in the respiration (e.g. hexonase), an enzyme participating in the phosphoric acid metabolism (e.g. alkaline phosphatase), an enzyme participating in the amino acid metabolism (e.g. glutamic acid dehydrogenase) and an enzyme participating in the cell membrane permeability (e.g. esterase) are respectively measured and the infection activity of the objective VA mycorrhizae infection agent is determined by the correlation between the number of spores and the enzymatic activities.