Inoculation of Arbuscular Mycorrhizal Fungi Improves Growth and Photosynthesis of Ilex paraguariensis (St. Hil) Seedlings

Abstract

Yerba mate (Ilex paraguariensis St. Hill.) is an important woody tree in South America, however the production of quality seedlings is a major problem. Microorganisms that promote plant growth have shown to be efficient biotechnologies in the production of seedlings. The arbuscular mycorrhizal fungi (AMF), it establishes symbiosis with several plant species and increases the accumulation of biomass and absorption of poorly mobile nutrients such as phosphorus. Here, we test the effects of two AMF species on growth, root architecture, phosphorus accumulation and gas exchange of yerba mate seedlings cultivated under different phosphorus levels. We used seedlings in a non-sterile soil, inoculated with AMFs Rhizophagus clarus SCT720A and Acaulospora colombiana SCT115A, and non-inoculated (control) treatment under five levels of phosphorus (0; 25; 50; 100 and 200% recommendation). After 90 days of AMF inoculation, plant dry biomass, root architecture and mycorrhizal colonization were determined and after 180 days, the same parameters plus photosynthetic rate, transpiration rate, stomatal conductance and P content were evaluated. AMF inoculation increased shoot and root dry biomass, total root length, root volume. Plants inoculated with AMF showed higher photosynthesis rate. Phosphorus content and mycorrhizal colonization were increased almost three times when inoculated with AMF. Our findings highlight the importance of AMF inoculation for Ilex paraguariensis seedlings production, reducing the time needed in nurseries to enhance tree performance. HIGHLIGHTS• Arbuscular mycorrhizal fungi (AMF) inoculation increases root development and photosynthesis of yerba mate.• The inoculation of AMF improves yerba mate growth and can reduce the time needed in nurseries.• No P supply was needed to produce I. paraguariensis seedlings inoculated with AMF.

Effects of arbuscular mycorrhizal fungus inoculation on the growth and nitrogen metabolism of Catalpa bungei C.A.Mey. under different nitrogen levels

“…Mycorrhizal symbiosis also affects photosynthesis (Auge ́, 2000). After colonizing roots, AMF could maintain the high gas exchange capacity of plants and enhance photosynthesis, which has also been documented in mycorrhizal Robinia pseudoacacia (Zhu et al, 2014), Gleditsia sinensis (Wang et al, 2019) and Ilex paraguariensis (Tomazelli et al, 2022). In particular, in most cases, we also recorded a significant positive correlation between the percentage of mycorrhizal colonization and photosynthetic characteristic parameters (p < 0.01, or 0.05; Supplementary data, Table S3).…”

“…These results were in keeping with those of previous studies. Several studies have shown that AMF colonization can improve the root architecture of woody plants, and directly affect the uptake of soil water and mineral nutrients by plants (Zhang et al, 2016;Gao et al, 2019;Tomazelli et al, 2022). In our study, compared with noninoculated treatment, AMF inoculation could significantly improve root architecture, enhance root activity, and stimulate root growth of C. bungei seedlings under moderate N concentration, while too low or too high N concentrations were not conducive to mycorrhizal effect.…”

“…Our study found that moderate N addition could significantly increase the colonization rate of R. intraradices and promote the growth of C. bungei seedlings, but excessive N could inhibit mycorrhizal colonization and the growth of seedlings, which was similar to the previous results in Camellia sinensis (Zhao et al, 2014), Sophora japonica (Yang et al, 2021). Several studies have shown that mycorrhizal symbiosis could promote the growth of woody plants (Turjaman et al, 2006;Outamamat et al, 2022;Tomazelli et al, 2022). However, the effects of AMF on plant growth can be altered by soil N levels.…”