Importance of light and CO₂ on the effects of endomycorrhizal colonization on growth and photosynthesis of potato plantlets (Solanum tuberosum) in an in vitro tripartite system

Abstract

A factorial analysis was conducted to investigate the effects of different levels of photosynthetic photon flux (PPF) and CO2 concentration on the interactions between the vesicular–arbuscular endomycorrhizal fungus Glomus intraradices and potato plantlets (Solanum tuberosum) cultured in an in vitro tripartite system. We observed that CO2 enrichment from 350 to 10000 ppm stimulated root colonization by the fungus, and that this stimulation was more pronounced under high PPF (300 μmol m−2 s−1) than low PPF (60 μmol m−2 s−1). Consistent with these observations, the effects of G. intraradices on dry matter production in potato plantlets were strongly dependent on the CO2 and PPF levels during cultivation. There was no significant effect of the mycorrhizal fungus on dry matter production at 350 ppm of CO2. However, under the high CO2 concentration, mycorrhiza had opposite effects on dry matter production depending on the PPF: a decrease (−21%) and a stimulation (+25%) of dry matter production after 2 wk of growth under low and high PPF, respectively, were observed in presence of G. intraradices relative to plantlets grown in its absence. Furthermore, in mycorrhizal plantlets grown under high levels of both PPF and CO2, the chlorophyll and carotenoid contents as well as the quantum yields of photosynthetic electron transport and the photochemical quenching qP of the chlorophyll‐a fluorescence measured near the PPF during growth were all higher than in non‐infected plantlets. Our results therefore indicate that mycorrhizal G. intraradices can alleviate the down regulation of photosynthesis related to sink limitation, and its effect on dry matter production is strongly dependent on the levels of CO2 and PPF during growth which determine the balance between the photosynthetic carbon uptake by the plantlets and the carbon cost by the fungus.

Molecular–Physiological Aspects of the AM Symbiosis Post Penetration

“…Anyhow, the outcome seems to be in case of beneficial mycorrhizal interactions an increased photosynthetic activity. This can be also seen from experiments under reduced photon fluxes or CO 2 concentrations, where the costs of mycorrhizal colonisation cannot be balanced by increased assimilation and negative effect of the fungus on plant growth become evident (Louche-Tessandier et al 1999). …”

Integration of mycorrhization and photoautotrophic micropropagation in vitro: feasibility analysis for mass production of mycorrhizal transplants and inoculants of arbuscular mycorrhizal fungi

“…However, no optimal environmental parameters have been determined with respect to mycorrhization-PM cultivation systems. For lighting and CO 2 concentration, previous studies concentrated mainly on the effect of interactions between lighting and CO 2 concentration on AMF function and development, as well as on the growth of plantlets in in vitro tripartite systems (Elmeskaoui et al 1995;Louche-Tessandier et al 1999;Gavito et al 2002). For substrate conditions, pH (Clark and Zeto 1996;van Aarle et al 2002), temperature (Addy et al 1994, 1998Wang et al 2002;Gavito et al 2003), and the interaction effects of atmospheric CO 2 concentration and soil temperature on P uptake by AMF were examined (Gavito et al 2003).…”

“…In the midnineties, two kinds of in vitro culture systems, tripartite (strawberry plant-mycorrhizal carrot root) (Elmeskaoui et al 1995) and bipartite (strawberry-AMF) (Cassells et al 1996), were developed for mycorrhization of micropropagated plantlets. For these systems, studies were performed on water uptake and stomatal conductance (Hernández-Sebastià et al 1999, the effects of light and CO 2 on the growth and photosynthesis of mycorrhizal plants (Louche-Tessandier et al 1999), and the use of mycorrhizal vitroplants in the micropropagation industry (Mark et al 1997). In particular, Voets et al (2005) recently developed an autotrophic culture system for the in vitro mycorrhization of potato plantlets with shoots grown exposed to air conditions.…”

Benefits of the Mycorrhizal Fungi in Tomato Leaves Measured by Open Photoacoustic Cell Technique: Interpretation of the Diffusion Parameters

“…The association increases the drought resistance of the plant and its photosynthetic rate, among other benefits that have been previously studied and are still under investigation [4][5][6][7]. Most of the studies regarding the symbiosis between mycorrhizal fungi and plants have been performed using conventional techniques (e.g., gas exchange techniques such as infrared gas analysis (IRGA) [8]).…”