Effect of corn steep liquor on lettuce root rot (Fusarium oxysporum f.sp. lactucae) in hydroponic cultures.

BACKGROUND: Recent reports indicate that organic fertilisers have a suppressive effect on the pathogens of plants grown under hydroponic systems. Furthermore, microorganisms exhibiting antagonistic activity to diseases have been observed in organic hydroponic systems. This study evaluated the effect of corn steep liquor (CSL) on controlling lettuce root rot disease [Fusarium oxysporum f.sp. lactucae (FOL)] in a hydroponic system. The effect of CSL and Otsuka A (a chemical fertiliser) on the inhibition of FOL in terms of mycelial growth inhibition was tested in vivo. RESULTS: Addition of CSL suppressed FOL infection rates. CSL inhibited FOL infection by 26.3-42.5% from 2 days after starting incubation. In comparison, Otsuka A inhibited FOL growth by 5.5-19.4%. In addition, four of 10 bacteria isolated from the nutrient media containing CSL exhibited inhibition zones preventing FOL mycelial growth. CONCLUSIONS: We found that CSL suppressed FOL in lettuce via its antifungal and biostimulatory effects. We suggest that activation of beneficial microorganisms present in CSL may be used to decrease lettuce root rot disease and contribute to lettuce root growth.

Improvement of sonocatalytic activity of TiO2 by using Yb, N and F-doped Er3+:Y3Al5O12 for degradation of organic dyes.

In this study, several up-conversion luminescence agents (Er(3+):Y3Al5O12, Er(3+):Yb0.2Y2.79Al5O12, Er(3+):Yb0.2Y2.79Al5N0.01O11.99, Er(3+):Yb0.2Y2.79Al5F0.01O11.99 and Er(3+):Yb0.2Y2.79Al5N0.01F0.01O11.98) were synthesized using sol-gel method. And then, the corresponding sonocatalyst (Er(3+):Y3Al5O12/TiO2, Er(3+):Yb0.2Y2.79Al5O12/TiO2, Er(3+):Yb0.2Y2.79Al5N0.01O11.99/TiO2, Er(3+):Yb0.2Y2.79Al5F0.01O11.99/TiO2 and Er(3+):Yb0.2Y2.79Al5N0.01F0.01O11.98/TiO2 coated composites) were prepared by sol-gel coating process. The synthesized up-conversion luminescence agents and their coated composites were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). And that, the sonocatalytic activities were detected through the degradation of Azo Fuchsine (AF) dye in aqueous solution by UV-vis spectroscopy. Some key influences such as heat-treated temperature and heat-treated time on the sonocatalytic activity of Er(3+):YbaY2.99-aNxFyAl5O12-x-y/TiO2 coated composite, as well as ultrasonic irradiation time and initial dye concentration on the sonocatalytic degradation were studied. The results showed that the doping of Yb, N and F into Er(3+):Y3Al5O12/TiO2 significantly enhanced the sonocatalytic activity of Er(3+):Y3Al5O12/TiO2 coated composite in the degradation of organic dyes. Particularly, Er(3+):Yb0.2Y2.79Al5N0.01F0.01O11.98/TiO2 coated composites with 3:7 M ratio heat-treated at 550 °C for 60 min showed the highest sonocatalytic activity. At last, the experiments also indicated that the Er(3+):Yb0.2Y2.79Al5N0.01F0.01O11.98/TiO2 coated composites has a good sonocatalytic activity to degrade other organic dyes under ultrasonic irradiation.