Diseases, especially caused by seed borne fungi, are among the factors decreasing yield and quality of wheat. Common bunt is also an important seed borne disease of wheat worldwide. The objective of the study is to determine the effects of clove, ginger, mint, oregano and thyme oils on the fungal load of wheat seeds. In addition, effects of the oils on the germination rates of bunt spores were investigated. Blotter method was used to determine the effects of different concentrations (0.05 -10%) of the oils on fungal load of wheat seeds. After incubation at 22°C for 7 days, seeds were investigated under stereomicroscope and fungi growing on the seeds were recorded. Germination rates of bunt spores were determined after incubation on water agar with different concentrations of oils. Highest doses of clove, mint and oregano oils totally inhibited the fungal growth on wheat seeds, but they also inhibited the germination of seeds. Lower doses failed to inhibit fungi on seeds, however they decreased or totally inhibited the germination of bunt spores. As a result, it was found that plant essential oils could be used against bunt disease of wheat as an alternative to fungicides.

Rosa damascena Mill. is a very fragrant member of Rosaceae family, exhibiting strong antioxidant and antimicrobial activity. In this study, in vitro cell cultures from Rosa damascena Mill. flower petals were established and the effects of precursor L-phenylalanine, the elicitor methyl jasmonate and light/dark treatments on the accumulation of characteristic rose volatile compounds, tocopherols and β-carotene in addition to the antibacterial activity of petal callus extracts were investigated with Solid-Phase Microextraction Combined with Gas Chromatography-Mass Spectrometry (GC-MS). The amount of β-pinene increased by 236 times when 500 µM Phe was added to the culture medium or under light treatment. Strong antibacterial activity from petal callus extracts, up to 2.6-fold compared to amikacin as well as original petal tissues, was obtained under dark treatment for P. aeruginosa ATCC 27853 and S. aureus ATCC 25923. These results revealed that petal callus extracts are sources of natural antioxidants and antibacterial compounds.

Boron (B) toxicity is a considerable mineral nutritional problem for crop production in arid and semi-arid regions worldwide. The effect of mannitol (M) in wheat seedlings that are tolerant and sensitive to excessive B was studied to reduce B toxicity symptoms. Plants were grown in a peat with different concentrations of boric acid (0, 30, 45, 60 mg kg −1 ) and treated additionally with M (0, 1, 5, 10 g kg −1 ). Seedlings grown for 8 weeks were harvested for root length, shoot length, and dry-weight measurements and analyzed for B content of leaves. Compared with control groups (no boric acid treatment), B toxicity caused reductions in root length, shoot length, and dry weight of both wheat cultivars. Significant increases on growth parameters were observed under B treatments, the greatest with 1 g kg −1 M application in a tolerant bread cultivar. On the other hand, 10 g kg −1 M application under 60 mg kg −1 B treatment gave also good results on root length in a sensitive durum cultivar. Significant decreases in leaf B content were observed under B treatments with all M applications in both wheat cultivars, the greatest with 5 g kg −1 M application. The results suggest that M applications may have a possible role in overcoming in B toxicity in wheat grown in the field.