Trichoderma

Lucini, Luigi, Colla, Giuseppe, Moreno, Maria Begoña Miras, Bernardo, Letizia, Cardarelli, Mariateresa, Terzi, Valeria, Bonini, Paolo & Rouphael, Youssef, 2019, Inoculation of Rhizoglomus irregulare or Trichoderma atroviride differentially modulates metabolite profiling of wheat root exudates, Phytochemistry 157, pp. 158-167 : 159

2.1. AM root colonization, Trichoderma concentration, growth responses and SPAD index

The percentage AM root colonization at the end of the experiment was significantly affected by the microbial inoculation treatment ( Table 1 ). No AM fungi colonization was recorded in the roots of the control wheat plants or in the substrate or seed treatments with T. atroviride . However, in the plants supplied with R. irregulare , the percentage of AM was around 32% ( Table 1 ). Moreover, the total number of Trichoderma colonies recovered from the growing media and roots in the four treatments ranged between 1.1 × 10ˆ 1 and 3.7 × 10ˆ 4 CFU g −1, with the highest values recorded in both the cases with substrate application and seed treatment with T. atroviride ( Table 1 ).

Concerning the effects of microbial inoculation on growth responses, our results showed that inoculation with R. irregulare elicited significant increases (+18%, 39% and 20%) in the shoot, root dry biomass and root-to-shoot ratio compared to the untreated plants, whereas inoculation with T. atroviride via a substrate drench or as a seed treatment yielded intermediate values ( Table 1 ). Similar to the effects on biomass production, the Soil Plant Analysis Development (SPAD) index in the microbial inoculation treatments was significantly higher (by 8% on average) than that obtained in the untreated wheat plants, irrespective of the microbial-biostimulant treatment ( Table 1 ).