Effect of shading and nitrogen fertilization on nitrogen metabolism, essential oil content and antimicrobial activity of Achillea millefolium

The Achillea millefolium L. is a perennial herb with important antibacterial, antifungal, anti-inflammatory, antitumoral, and antioxidant properties. This research aimed to investigate the effect of shading (75%; black net) and nitrogen fertilization (0, 75 and 150 kg urea ha-1) on the nitrogen metabolism, essential oil yield and antimicrobial activity of A.millefolium at vegetative- and reproductive-stage. The evaluated parameters varied depending on the organ and the phenological stage of the plant considered. Overall, our findings indicated that shading decreased nitrogen assimilation. Decreased activities of nitrate reductase and glutamine synthetase were observed on shaded plants during reproductive and vegetative stages, respectively. Nitrate and total amino acid levels increased in shaded plants at the vegetative stage. Regarding nitrogen supply, the improved nitrogen metabolism and essential oil yield values were accompanied by intermediate concentrations of urea (75 kg ha-1). Plants fertilized with 75 kg urea ha-1 produced the highest amino acids concentration (vegetative stage), ammonium concentration (vegetative stage) and essential oil yield (reproductive stage). Shading or nitrogen supply did not influence the microbial activity of A. millefolium essential oil.However, the essential oil of leaves and flowers were highly effective against fungi and bacteria, especially gram-positive bacteria. In conclusion, the current study showed that full light and 75 kg urea ha-1 enhanced the nitrogen metabolism of A. millefolium in both vegetative and reproductive stages.

Nitrogen losses through leachate and its distribution.

A column experiment was conducted to elucidate information on the nitrogen losses with clay loam and sandy clay loam soil collected from the farm of UPASI, Coonoor and UPASI, Valparai respectively with 5 levels of nitrogen viz., 0, 250, 375, 500 and 625 kg ha(-1) and two different rainfall intensities viz., i1 = 40 mm hr(-1) (medium rainfall intensity) and i2 = 60 mm hr(-1) (high rainfall intensity). The losses of nitrogen fractions through leachate were analyzed for a month period. The results indicated that the nitrogen application increased the concentration of NH4-N and NO3-N in the leachate collected under both the soils. The NH4-N concentration was high in the leachate collected under sandy clay loam soil (33.99 mg l(-1)) whereas N03-N concentration was high in the leachate collected under clay loam soil (17.75 mg l(-1)). Between the rainfall intensities, the NO3-N concentration was high in the leachate collected from clay loam soil under medium rainfall intensify and the reverse trend was observed under sandy clay loam soil. The distribution of NH4-N and NO3-N was higher in the clay loam soil than sandy clay loam soil. The NH4-N content increased with increase in the depth of soil column under both the soil. The N03-N distribution followed the similar trend under sandy clay loam soil. But in the clay loam soil, the highest N03-N content was detected at 14-21 cm depth under medium rainfall intensity.

Investigation of the reaction product of certain 3- [2- [bromophenyl] -2-oxoethylidene] -1,3-dihydro-2Hindol-2-ones with some nucleophiles

The addition of some nucleophilic reagents to certain 3-[2-[3- or 4-bromophenyl]-2-oxo-ethylidene]-1,3-dihydro-2H-indolones VIa-j was investigated. The anomalous behavior observed during the addition of phenylhydrazine or hydroxylamine indicated a Michael reaction. The structures of the products were established on the basis of their elemental and spectral analyses. A discussion of the experimental findings was presented