ネギ実生の生長に及ぼすＶＡ菌根菌胞子接種濃度ならびに床土への炭化材添加の影響

Abstract

The means and spore density of inoculation with vesicular-arbuscular mycorrhizal (VAM) fungal (Glomus etunicatum) spores and addition of carbonized material to bed soil on seedling growth in Welsh onion (Alliuin fistulosum L.) were investigated in relation to VAM fungus infection.1. Growth was enhanced by VAM fungus infection in both 'Green-negi' and 'Ishikurafutonegi'. In 'Green-negi', greater growth enhancement through host-fungus symbiosis was obtained in plants inoculated with 1000 spores•g-1 rather than 3000 spores•g-1 inoculum. Growth of these plants was further accelerated when 70 g of carbonized material were mixed with 10 kg of bed soil.2. VAM fungus infection promoted both leaf emergence and leaf blade elongation, especially in leaves above the third true leaf. In 'Green-negi', growth promotion was largest in leaves located in higher leaf position, and further growth was promoted by the addition of carbonized material to bed soil. Thickening of both leaf blades and leaf sheaths, and an increase in number of main roots were observed in VAM fungus-infected plants.3. The rate of VAM fungus-infected portions in a whole root system of Welsh onion fluctuated, increasing initially (1st stage), remaining constant (2nd stage), and then decreasing (3rd stage). The infected portions in a whole root system increased when carbonized material was mixed with bed soil.4. VAM fungal hyphae grew on the surface of the carbonized particle.