Sulfur deficiency assay with MGRL agar medium
After germinating on MS medium for 5 days, seedlings were rinsed gently with sterilize water and transferred to MGRL agar medium with high (1520.9 µM) or low (20.9 µM) sulfate concentrations and grown for 7 days.
To measure the influence of TMTM on seedling´s fresh and dry weights, a 3-compartments Petri dish (92 mm in diameter, Sarstedt, Germany) was used. Two compartments were filled with MGRL agar medium, both containing either high or low sulfate concentrations. A sheet of sterilized paper was put in the third empty compartment, to which 10 µL sterilized water and a 10 µL mixture of 0, 10, 100 or 1000 µg TMTM dissolved in dichloromethane was applied.
For monitoring root growth, 5 days-old seedlings were transferred onto high or low sulfate MGRL agar medium on a square plate (100 x 100 x 20 mm; Sarstedt, Germany). A sheet of sterilized paper was put on to the bottom of the plate, and TMTM was applied onto it as described above. Plates were incubated vertically. Root length was measured directly after transfer and after 7 days of treatment.