Predicting Mycorrhizal Dependency of Troyer Citrange on Glomus fasciculatus in California Citrus Soils and Nursery Mixes

Abstract

In a greenhouse experiment the mycorrhizal fungus, Glomus fasciculatus, significantly increased growth of Troyer citrange (Poncirus trifoliata L.) (TC) seedlings in 20 of 26 methylbromide‐fumigated citrus soils from southern California. Of the six soils in which G. fasciculatus provided no growth increase, two were greenhouse soils, three were nursery soils, and only one was a field soil. Glomus fasciculatus increased foliar P, K, and Cu concentrations and decreased foliar Mg and Na concentrations of TC grown in the majority of the 26 citrus soils. Foliar concentrations of P, K, Ca, Na, Zn, Mn, Cu, and Fe from either mycorrhizal or nonmycorrhizal TC could not be significantly correlated with the mycorrhizal dependency of TC in the soils studied. A positive correlation was observed between foliage concentrations of Mg in nonmycorrhizal TC and mycorrhizal dependency. Mycorrhizal dependency of TC was also positively correlated with soil pH and inversely correlated with extractable soil P (bicarbonate), Zn, Mn, Cu, percent organic matter, and cation exchange capacity. In the fumigated soils studied, it was highly probable that inoculations with G. fasciculatus would induce significant growth response in TC provided the soils had <34 ppm extractable P, 27 ppm extractable Mn, 12 ppm extractable Zn, or 3% organic matter. The magnitude of the mycorrhizal dependencies of TC on G. fasciculatus in the 26 citrus soils were accurately predicted with equations which used soil P, Mn, Zn, and also Cu and pH as independent variables.

DEVELOPMENT OF EXTERNAL HYPHAE BY DIFFERENT ISOLATES OF MYCORRHIZAL GLOMUS SPP. IN RELATION TO ROOT COLONIZATION AND GROWTH OF TROYER CITRANGE

“…Menge et al (1982) found that the mycorrhizal dependency of Troyer citrange on G. fasciculatus isolate 0-1 in 26 citrus soils from California was inversely correlated with soil P, Zn, Mn, Cu, percentage organic matter and cation exchange capacity, and was positively correlated with soil pH. In general, arid soils are alkaline in pH, as was the California soil we used (pH 7-3), whereas soils from humid regions, such as Florida, have a pH below 7 (Brady, 1974).…”

“…For citrus the magnitude of growth response produced by VAM is referred to as mycorrhizal dependency which is determined in part by the efficiency of the fungus. Mycorrhizal dependency may vary with cultivar, soil factors and mycorrhizal fungus (Menge et al, 1978(Menge et al, , 1982Nemec, 1978). In a test of six citrus cultivars, Nemec (1978) found that differences in efficiency of three Glomus species varied with both rootstock and phosphorus fertilization.…”

Magnesium deficiency in citrus grown in the Gisborne district of New Zealand

“…Research has shown that considerable variation exists between mycorrhizal species in their effect on citrus nutrition and growth and between citrus species in their dependence on mycorrhiza (Camprubi & Calvet 1996). of the few published studies on the effect of mycorrhiza on Mg nutrition of citrus, three showed that inoculation with mycorrhiza reduced Mg uptake (Menge 1982;Rocha et al 1995;Souza 2000) and one found an increase (Gendiah & Zaghloul 1997). Melloni & Cordoso (1999) found that the relationship between Mg uptake and the amount of mycorrhizal mycelium on the roots varied depending on the species of citrus grown.…”

Influence of adverse soil conditions on the formation and function of Arbuscular mycorrhizas

“…In short, some mycorrhizal fungi may not readily adapt to soils with a pH unlike that of the soil of their origin, thus pH may constrain establishment of arbuscular mycorrhizas. Studies suggesting that this relationship may exist involved the direct liming of soils (Kucey and Diab, 1984;Newbould and Rangeley, 1984), analyses of arbuscular mycorrhizas across diverse soil types (Sylvia et al, 1993b;Menge et al, 1982;Skipper and Smith, 1979), and various management treatments that included fertilizing or physically modifying the soil (e.g. organic amendments, Soedarjo and Habte, 1993).…”