Growth of zinnia, Italian ryegrass, and alfalfa and their remediation effects in diesel oil-contaminated soils.

Our objective in this study was to compare the growth of zinnia, Italian ryegrass, and alfalfa, and their remediation effects in oil-contaminated soils. The soils were prepared by mixing 2, 4, or 8% diesel oil by weight with soil. The plant height and dry weights of shoots and roots were highest for zinnia in the 2 and 4% oil treatments, and highest for Italian ryegrass in the 8% oil treatment. The reduction ratios in soil total petroleum hydrocarbons concentration (TPH) for 3 plants were lower in the 4 and 8% oil treatments than those in the 2% treatment. The reduction ratios for Italian ryegrass and zinnia contaminated with 2, 4, and 8% diesel oil treatments were significantly higher than those for alfalfa and the non-cultivation treatment at 45 days after sowing, and there were no significant differences in reduction ratios between Italian ryegrass and zinnia. The reduction ratio of soil TPH concentration brought about by zinnia was also comparable to that of Italian ryegrass. Therefore, we conclude that zinnia shows growth and remediation effects that are equivalent to those of Italian ryegrass, in soils contaminated with less than 8% oil.

Relationships between root growth of Zinnia hybrid "profusion orange" flowers and phytoremediation of oil-contaminated soil.

Relationships exist between plant root growth and the phytoremediation of oil-contaminated soils. In a previous study, we demonstrated that zinnia flowers are well suited for the remediation of oil-contaminated soil. In this study, our goal was to quantify the relationship between zinnia root growth and purification of oil-contaminated soils. Three treatments were used: (1) cultivation of zinnia in oil-contaminated soil (contaminated pots), (2) cultivation in non-contaminated soil (non-contaminated pots), and (3) contaminated soil with no cultivation and only irrigation (irrigated pots). Growth of the Zinnia plants, including their roots, was significantly reduced in the contaminated pots compared with the noncontaminated pots. The soil dehydrogenase activity increased between 45 and 90 days after planting in all parts of the contaminated pots, especially the upper parts. The soil total petroleum hydrocarbon (TPH) concentrations in the contaminated pots decreased throughout the study period. Interestingly, the soil dehydrogenase activity increased, and the soil TPH concentration decreased even in lower parts of the pots where there was very little root growth. Therefore, the cultivation of plants can have a remediative effect on oil-contaminated soil even below the depth reached by the plant roots.

Disinfection by Ozone Microbubbles Can Cause Morphological Change of Fusarium oxysporum f. sp. melonis Spores.

To investigate the difference in the disinfectant efficiency of ozone microbubbles (O3MB) and ozone millibubbles (O3MMB), the morphological change of the treated Fusarium oxysporum f. sp. melonis spores was observed with scanning and transmission electron microscopies (SEM and TEM). The disinfectant efficiency of O3MB on F. oxysporum f. sp. melonis spores was greater than that of O3MMB. On observation with SEM, it was revealed that morphological change of F. oxysporum f. sp. melonis spores was caused by O3MB and O3MMB, and damage to the spore surfaces by O3MB occurred sooner than that by O3MMB. On observation with TEM, it was furthermore confirmed that F. oxysporum f. sp. melonis spores treated with O3MB induced wavy deformation of cell membrane and the intracellular change different from that with O3MMB. Therefore, the greater disinfection efficiency of O3MB was suggested to be caused due to the function of the MB in addition to the oxidative power of O3.

Effects of basal fertilizer and perlite amendment on growth of zinnia and its remediation capacity in oil-contaminated soils.

In a previous study we demonstrated that Zinnia hybrida 'Profusion White' can be effective in the remediation of oil-contaminated soil. However, the rates of removal of total petroleum hydrocarbons (TPH) were greatest in soils containing 9000 mg/kg TPH and less in soils with higher concentrations of TPH. This study was conducted to investigate the effects of basal fertilizer rates and perlite amendments on the growth of zinnia and its remediation capacity in soils with TPH concentrations of 26,000 mg/kg. METHODOLOGY: Soils were prepared with or without TPH at an initial concentration of 26,194 mg/kg, and then each of these soils was amended with either a basal fertilizer rate with or without 20% perlite, or twice the basal fertilizer rate with or without 20% perlite. Pots were prepared with the following treatments in these soils: contaminated soil planted with zinnia (planted-contaminated), uncontaminated soil planted with zinnia (planted-uncontaminated), and contaminated soil not planted with zinnia (unplanted-contaminated). Plant growth, soil dehydrogenase activity (DHA), and TPH concentrations were analyzed at 30 and 60 days after sowing. RESULTS: Plant growth in oil-contaminated and uncontaminated soils was superior in pots with twice the basal fertilizer and with perlite. The DHA values in the planted-uncontaminated treatments were significantly lower than those in the planted-contaminated and unplanted-contaminated treatments. However, the effects of basal fertilizer amount and perlite on the DHA values of the soils were small. The TPH concentrations in the planted-contaminated soils were significantly lower than those in the unplanted-contaminated soils after 30 and 60 days. Furthermore, the TPH concentrations in the planted-contaminated soils were lowest in pots with twice the basal fertilizer and with perlite. CONCLUSIONS: These results show how phytoremediation of soils with high levels of oil contamination by Z. hybrida 'Profusion White' can be practically enhanced by amending the soil with perlite and higher basal fertilizer rates.

Screening of plants for phytoremediation of oil-contaminated soil.

Several species of ornamental flowering plants were evaluated regarding their phytoremediation ability for the cleanup of oil-contaminated soil in Japanese environmental conditions. Thirty-three species of plants were grown in oil-contaminated soil, and Mimosa, Zinnia, Gazania, and cypress vine were selected for further assessment on the basis of their favorable initial growth. No significant difference was observed in the above-ground and under-ground dry matter weight of Gazania 180 days after sowing between contaminated and non-contaminated plots. However, the other 3 species of plants died by the 180th day, indicating that Gazania has an especially strong tolerance for oil-contaminated soil. The total petroleum hydrocarbon concentration of the soils in which the 4 species of plants were grown decreased by 45-49% by the 180th day. Compared to an irrigated plot, the dehydrogenase activity of the contaminated soil also increased significantly, indicating a phytoremediation effect by the 4 tested plants. Mimosa, Zinnia, and cypress vine all died by the 180th day after seeding, but the roots themselves became a source of nutrients for the soil microorganisms, which led to a phytoremediation effect by increase in the oil degradation activity. It has been indicated that Gazania is most appropriate for phytoremediation of oil-contaminated soil.

Effects of ozone microbubble treatment on removal of residual pesticides and quality of persimmon leaves.

This study investigated the effects of ozone microbubble (OMCB) treatment on the removal of residual fenitrothion (FT) and benomyl pesticides from red and green persimmon leaves, and also the treatment effect on the leaf colours, physical properties and flavour. The continuous bubbling OMCB treatment was more effective than the non-bubbling OMCB treatments at reducing the FT and benomyl agricultural pesticide residues from both the red and green persimmon leaves. Moreover, the bubbling OMCB treatment had no effect on the colour and pulling strength of the leaves. These results indicate that the treatment by bubbling OMCB is an extremely effective method for removing the residues of FT and benomyl in persimmon leaves and has relatively little effect on leaf quality characteristics.

Distribution of amylose, nitrogen, and minerals in rice kernels with various characters.

The distribution of chemical constituents is known not to be even within a rice kernel. To improve the eating quality of rice or to give it some special traits by adjusting the milling intensity, we investigated the distribution of amylose, nitrogen (N), and specific minerals (P, K, Mg, Ca, and Mn) in rice kernels of 11 cultivars with various characteristics cultivated under similar conditions. The distributions of these constituents were determined using flour samples prepared consecutively by abrasive milling from the outer to the inner portions of hulled rice. In all the cultivars tested, N and the minerals were found to be more abundant in the outer than in the inner portion, but amylose was rich in the inner portion. P, Mg, K, and Mn were extremely rich in the outer portion, while N and Ca were only relatively rich there. Koshihikari, which is the most popular cultivar in Japan because of its excellent eating quality, showed the highest Mg/K ratio in the outermost portion of polished rice. The color of flour samples became pure white going from outside portions toward the center of the kernel, even if the sample was from red rice or purple-black rice because only the surface of hulled rice contains pigments. These findings suggest that the outer portion contains various compounds other than starch and the inner portion contains relatively pure starch. Rice palatability and other characteristics can be improved through controlling the degree of milling using the biased distribution of chemical constituents within a rice kernel.