Mycorrhiza Effect on Maize P Uptake from Phosphate Rock and Superphosphate

Abstract

Low available phosphorus (P) is a serious constraint for crop production in acidic tropical soils. Economical yields in these environments require application of large amounts of costly nitrogen (N) and P fertilizers. Although phosphate rock (PR) has been proposed as a less expensive P source, the slow P release to the soil limits its use for annual crops. The objective of this work was to examine the effect of inoculating a nonsterile acidic soil with vesicular arbuscular mycorrhizal (VAM) Gigaspora margarita on PR dissolution and P uptake by aluminum (Al)-tolerant maize inbreds. Three maize inbreds from CIMMYT, at Cali, Colombia, ranked as Al-tolerant and one local breed ranked as Al-susceptible were seeded in 4-kg pots filled with a soil of pH 4.1 and 2.5 mg kg 21 available P. Inoculants (Gigaspora margarita and indigenous VAM), P fertilizer (Riecito phosphate rock and triple superphosphate), and the four inbreds were arrainged in a factorial design (2 6 2 6 4) with four replications. Plants were harvested 35 days after seeding, and P was determined in shoots. Four 2.5-cm-diameter soil cores were obtained from each pot to determine root length (two cores), root colonization (one core), and available P (one core). The inoculation with Gigaspora margarita caused a reduction in root length but better root colonization, 55% increase in P uptake, and 27% increase in shoot growth. When PR was used as fertilizer, plant growth was reduced in both roots and shoots. However, when PR was used in the presence of Gigaspora margarita, 2058 inbreds had 13% longer roots and shoot growth was the same as shoots fertilized with triple superphosphate. Our data suggest that inbreds exhibit different abilities to acquire P from PR under the influence of Gigaspora margarita fungi.

Carbon investment into mobilization of mineral and organic phosphorus by arbuscular mycorrhiza

“…Burghelea et al (2015) observed in a similar approach as ours, that over 124 days, AM mycorrhized plant growth was enhanced in presence of rhyolite rocks, due to an efficient P mining. Different authors have demonstrated the ability of AMF to mobilize P from AP, e.g., Rhizophagus fasciculatus and Rhizophagus tenuis (Powell and Daniel 1978), Rhizophagus manihotis (Ness and Vlek 2000), Rhizophagus clarum (Alloush and Clark 2001), and Gigaspora margarita (Ramirez et al 2009), and Koele et al (2014) (mean values ± standard error, n = 3). Within each P source and day, treatments with significant differences are indicated by different small letters (p < 0.05) as analyzed by one-way ANOVA.…”

Arbuscular mycorrhizal fungus influence maize root growth and architecture in rock phosphate amended tropical soil

“…Ramirez et al (2009) also reported a reduction in maize growth in response to RP application and a reversal of the effect by inoculation of the AM fungus Gigaspora margarita W.N. Becker & I.R.…”

Growth benefits provided by different arbuscular mycorrhizal fungi to Plantago lanceolata depend on the form of available phosphorus

“…These Ca-phosphate species are often denoted by the term rock phosphates if they originate from a marine diagenetic mineral deposit [4,22]. A number of plant-mycorrhiza studies have demonstrated that AMF can successfully mobilize the phosphorus in apatites or at least, can significantly contribute to the solubilization of these P minerals, e.g., Glomus manihotis [25]; Glomus fasciculatus and Glomus tenuis [26], Glomus clarum [27] and Glomus margarita [28]. In root organ cultures it was shown that the extraradical mycelium (ERM) of Rhizophagus irregularis (formely known as Glomus intraradices) was able to release orthophosphate from hydroxyapatite, and to a lesser extent, also from a low-reactive rock phosphate mineral [29].…”