Analyzing the Effect of Arbuscular Mycorrhizal Fungi and Plant Growth-Promoting Bacteria Inoculation over the Growth of Tomatoes in a Martian Regolith Analog: Perspectives for Martian Agriculture.

Abstract

For future Mars colonization, crop production will be a challenge due to the chemical composition of the Martian Regolith, which contains perchlorates and heavy metals. This research was conducted to determine if the use of Arbuscular Mycorrhizal Fungi (AMF), Plant Growth-Promoting Bacteria (PGPB), and fertilization have a positive effect on tomato growth in a Martian Regolith Analog. The analog contains 52.54% SiO₂, 1.81% TiO₂, 17.66% Al₂O₃, 9.46% Fe₂O₃, 0.145% MnO, 3.43% MgO, 7.09% CaO, 3.95% Na₂O, 1.96% K₂O, and 0.55% P₂O₅. Two hundred and forty tomato plants were grown for 45 days. One hundred and twenty tomato plants grown over perchlorate-polluted analog (1% m/m) died in less than 2 weeks, while 120 tomato plants grown in a non-polluted analog survived. Forty-eight plants supplemented with Long-Ashton solution increased their shoot length 100% more than the control plants and the plants inoculated with the commercial AMF formulation TM-73^MR and PBB; the latter showed 25% mycorrhizal colonization. There was no significant difference between the growth parameters of inoculated plants and non-inoculated plants. However, there was a significant difference compared to the plants supplemented with Long-Ashton solution. The perchlorate is toxic to tomato plants, and the metal content of the analog was not a limiting factor for tomato growth or AMF colonization.