Efficiency of Some Plant Essential Oils on Root-Knot Nematode Meloidogyne incognita

During the last few decades, researchers have been in the search for environmental friendly ways to cope with agricultural pests, instead of using chemical pesticides. The use of essential oils has a high potential to become an alternative control strategy against plant parasitic nematodes. This study was conducted to determine the toxicity of 10 essential oils （Artemisia absinthium, Citrus bergamia, Eucalyptus citriodora, Hypericum perforatum, Lavandula officinalis, Mentha arvensis, Ocimum basilicum, Piper nigrum, Thymus serpyllum and Zingiber officinale） against the second stage juveniles of the root-knot nematode Meloidogyne incognita. The aqueous solutions of these essential oils have been applied to the second stage juveniles in three different concentrations （1%, 3% and 5%） at four different application time intervals （12, 24, 48 and 72 h）. The interactions between the variables have been examined with repeated measure analysis of variance （ANOVA）. This showed that the interactions of essential oil-time and essential oil-concentration were statistically significant, and it is concluded that L. officinalis, A. absinthium, P. nigrum, C. bergamia and M. arvensis have the most toxic effect in all concentrations and times, respectively.

Bioactive compounds and antioxidant activities of cold-pressed seed oil

Ten cold-pressed oil from 6 herb plant seeds （sesame, fax, saffower, pumpkin, tomato and hemp） and 4 woody plant seeds （camellia, almond, walnut and peony） were analyzed to determine bioactive compounds content, including tocopherols, phytosterols and phenolics, as well as their antioxidant activities. Total tocopherols content ranged from 161.11 mg/kg in camellia seed oil to 1,072.51 mg/kg in tomato seed oil. Tomato seed oil had the highest total phytosterols （708.89 mg/100 g） and phenolics content （20.27 mg SAE/100 g）,whereas, saffower seed oil has the lowest total phytosterols （173.75 mg/100g） and walnut kernel oil contained the lowest phenolics （2.32 mg SAE/100 g）, respectively. Tomato seed oil exhibited the strongest ferric-reducing antioxidant power （FARP, 311.36 μmol/100 g） and 2,2-diphenyl-1-picrylhydrazyl （DPPH） radical scavenging activity （56.40 μmol/100 g）, while camellia seed oil had the lowest FRAP value （34.83 μmol/100 g） and fax seed oil had the lowest DPPH value （2.75 μmol/100 g）. Correlation coeffcient was determined as 0.647 and 0.863 between FRAP value and total tocopherols and phenolics, and 0.673 and 0.711 between DPPH value and total tocopherols and phenolics （p 〈 0.05）, respectively. This result indicated the antioxidant activities （FRAP and DPPH） were highly correlated with total tocopherols and phenolics content of oil. This study will be very useful for comprehensive utilization of all 10 cold-press oils.

Ecological Remediation of Hydrocarbon Contaminated Soils with Weed Plant

Considerable efforts have been undertaken to accelerate the breakdown of existing anthropogenic petroleum hydrocarbons （PHCs） by appropriate in situ remediation technologies. In situ phytoremediation, using higher plants to remove, stabilize, degrade, and/or metabolize hazardous contaminants, has emerged as a promising green technology for cleaning up environments contaminated with PHCs. Weed plants are generally considered to have great potential for use in phytoremediation due to their extensive fibrous root systems and relatively robust characteristics, thus helping establish a strong rhizosphere through contaminated soils. In this review, some important mechanisms involved in phytoremedation of PHC contaminated soils, including phytoaccumulation, phytostabilization, phytodegradation, phytovolatilization, and rhizodegradation, were summarized and discussed. In recent years, a large number of laboratory approaches have been developed to further enhance the phytoremediation efficiency of PHC contaminated soils. The success of these laboratory studies has encouraged researchers to attempt phytoremediation of PHC contaminated soils in the field. However, many limitations still exist in order to successfully apply laboratory experiments to trials in the field.

Influence of Ectomycorrhizal Fungi on Absorption and Balance of Essential Elements of Pinus tabulaeformis Seedlings in Saline Soil

Pinus tabulaeformis seedlings were grown under a factorial design to measure biomass accumulation and P, Na and K concentrations of plants, with 3 different ectomycorrhizal fungus (EMF) strains (Boletus edulis, Xerocomus chrysenteron and Gomphidius viscidus) and two P treatments (with or without extra P). Growth and mineral nutrition of pine seedlings were stimulated by three EMF under salinity stress. Na concentrations were changed and plant K and P concentrations were increased significantly by EMF. Adding extra P made no difference in accumulation of seedlings biomass, and did not assist element absorption of plants. Although three strains of EMF can all enhance the tolerance of pine seedlings to salinity stress, they may utilize different mechanisms because of different performance in absorption of elements. The increased P and K accumulation and the balance of ion concentrations might be due to the enhanced tolerance of EMF-inoculated plants to saline conditions.