Responses of Six Species of Vesicular‐arbuscular Mycorrhizal Fungi and Their Effects on Soybean at Four Soil Temperatures

Abstract

SUMMARYThe effects of four soil temperatures on colonization of soybean roots, sporulation and enhancement of plant growth by six species of vesicular-arbuscular (VA) mycorrhizal fungi were tested. The mean values for all fungus and plant variates in three tests were generally greatest at 30 °C and lowest at 18 °C. Four fungus species, Glomus claroideum, Glomus datum, Gigaspora pellucida, and Gigaspora gregaria, produced the greatest number of spores per gramme of colonized root at 24 °C, while Glomus mosseae and Acaulospora laevis reached their maximum at 30 °C. Gigaspora gregaria had its maximum percentage of root colonization at 36 °C, Glomus mosseae reached its maximum at 24 °C, while all other species had maximum root colonization at 30 °C. Glomus claroideum and Acaulospora laevis were the only species which had maximum root colonization and sporulation occurring at the same temperature, 30 °C. Spore diameter was generally less at 30 than 24 °C, but this varied with fungus species and test. Soybean flower numbers, pod set and seed yield varied considerably in the three tests, but plant height was little affected by soil temperature or by fungus species. Generally, plants colonized with Glomus mosseae had an increased plant response and those colonized with Acaulospora laevis had a depressed plant response. There was considerable variation in plant response to various combinations of temperature and fungus species, with both growth stimulatory and growth repressive effects occurring.

Arbuscular mycorrhizal fungi altered the hypericin, pseudohypericin, and hyperforin content in flowers of Hypericum perforatum grown under contrasting P availability in a highly organic substrate

“…In particular, it has been shown that AM fungi usually increase flower amount, the number of flowering plants in a stand, or flowering earliness (Schenck and Smith 1982;Gaur et al 2000;Scagel 2004;Perner et al 2007;Bunn et al 2009;Asrar et al 2012;Bona et al 2015). However, it also has been found that AM fungi can have no effects on flowering (Linderman and Davis 2004), delay its onset, or increase its duration (Schenck and Smith 1982;Dubský and Vosátka 2000;Saia et al 2014a;Jin et al 2015). Such effects could depend on both the competition for N and photosynthates between AM fungi and flowers (Johnson et al 1982) and the ability of AM fungi to reduce nutrient deficiency or other stresses for the host plant.…”

Mycorrhizal symbiosis has contrasting effects on fitness components in Campanula rotundifolia

“…Myorrhizal symbiosis may affect plant reproduction also without affecting vegetative parameters (Schenck & Smith, 1982;Pendleton, 2000;Philip et al ., 2001). It is possible that these effects are mediated by hormones since hormone levels are altered in mycorrhizal plants (Ludwig-Müller, 2000).…”

Efficacy of Endomycorrhizal‐fungus Isolates and Inoculum Quantities Required for Growth Response*

“…Comparison of efficacy have been made with unknown quantities of inoculum (Mosse, 1975;Powell, 1979;Menge et al, 1980;Bagyaraj & Sreeramulu, 1982;Poweil, Clark & Verberne, 1982) or inoculum concentrations based upon spore numbers (Carling, Brown & Brown, 1979;Schenck & Smith, 1982). However, the spore numbers in inoculum often have been poorly correlated with the percent of VAM-roots in the inoculated plants (Daft & Nicolson, 1969;Daniels, McCool & Menge, 1981;Smith, 1981).…”