Volume 18, Issue 44 (10-2009)
Abstract
Hyoscyamus is one of the medicinal plants, rich in tropane alkaloids. In this research the effects of nitrate and ammonium on production of secondry metabolites and other physiological parameters, were investigated. The results indicated that when nitrate and ammonium were both present in nutrient solution and ammonium concentration was lower than nitrate, dry and fresh weight of root and shoot increased. However, by increasing ammonium concentration, plant growth decreased. With increased concentra-tions of ammonium, root/shoot ratios were decreased. Nitrate reductase activity increased in both nitrate and ammonium fed plants. However, the higher ratio of ammonium to nitrate led to a decreased NRA. Alkaloid content (sum of hyoscyamine and scopolamine) increased in both nitrate and ammonium fed plants. However, the higher the ratio of ammonium to nitrate, the lower the alkaloid content.
Volume 18, Issue 49 (11-2006)
Abstract
The Complex formation reaction between iodine with tetrabutylammonium halides (TBAX) has been studied spectrophotometrically in chloroform solution at 25ºC. Various aspects of the spectra of iodine in the presence of various concentration of different tetrabutylammonium halides have been discussed in terms of electronic specifications of iodine and halides. In the case of tetrabutylammonium iodide and at high concentrations of iodine, both 1:1 (I3-) and 2:1 (I5-) complexes have been formed. Formation constants of charge transfer complexes were evaluated from the computer fitting of the absorbance-mole ratio data and found to vary in the order: TBAI>TBABr>TBACl>TBAF.
