Effects of plant root extracts on growth of Trifoliate orange rootstocks inoculated with arbuscular mycorrhizal fungus under salinity conditions
This research aimed to evaluate how the plant extracts and arbuscular mycorrhizal fungi (AMF) can alleviate the salinity negative impacts on rootstocks growth. Targeting on this, two experiments were carried out in a greenhouse. In the first one 3 levels of NaCl (0, 75 and 150 mM) and 3 treatments (no inoculation, inoculation with AMF, and AMF with millet root extracts - MRE) were evaluated. The trifoliate orange (Poncirus trifoliata Raf.) was used as host plant and Gigaspora margarita as inoculum. The AMF colonization, total fresh weight (TFW) and root fresh weight (RFW) of trifoliate orange roots were benefited by the addition of MRE. The second experiment was carried out in the same conditions, except for NaCl levels (0, 300 and 600 mM), and the treatments (no inoculation, inoculation with AMF, and AMF with bahiagrass root extracts - BRE). The alleviation effects of BRE were observed in the TFW and RFW at 0 and 300 mM of NaCl. A third experiment was carried out in vitro to evaluate the effect of these extracts on the hyphal growth of AMF under salinity conditions. The petri dishes contained 3 treatments (agar only, with MRE and with BRE) with 3 levels of NaCl (0, 75, and 150mM). Increases in NaCl concentration induced decreases in the hyphal growth. Treatment with MRE and BRE, however, alleviated the effects of NaCl on the inhibition of AMF hyphal growing.