Partly dehydrated tobacco leaf tissue (Nicotiana rustica), stripped of the lower epidermis, was used to study the effect of kinetin on the rate of rehydration. Depending on the rate of rehydration in untreated tissue, kinetin either increased or decreased rehydration rates. The response to kinetin was very rapid and could be discerned in less than 2 minutes. On extensive dehydration, the tissue...

Logistic curves were fitted to sigmoidal growth data obtained from tobacco (Nicotiana rustica L.) callus grown on media prepared with 0.1, 0.03, 0.01, and 0.003 m sucrose. Analysis of the growth curves indicated that final yields and specific growth rates were influenced by the initial sucrose concentration. Growth yields from the four treatments were similar (0.61 +/- 0.04 gram dry tissue per ...

Nicotine is a natural water-soluble alkaloid obtained from the dried leaves and stems of tobacco plants (Nicotiana tabacum and Nicotiana rustica), with amounts of 0.5%-8% by weight. Because this substance has an addictive potential, leaves or products of tobacco have been sold as snuff, chewing tobacco, cigarettes, cigars and pipe tobacco. Nicotine is also used for therapeutic purposes, such as...

A 19S particle was purified from tobacco (Nicotiana rustica) leaf cells. Its density was determined as 1296 g/cm3 in Cs2SO4-DMSO gradients, indicating the presence of RNA and protein. Polyacrylamide gel electrophoresis (PAGE) revealed eight distinct proteins in the range of 20-30 kD and RNA in the range of 70-80 nucleotides. Electron microscopic examination showed the same raspberry-shaped stru...

The grana of chloroplasts of starch-free leaves of Nicotiana rustica are described in detail. Leaf sections were fixed in 2.5 per cent KMnO(4) and embedded in mixtures of butyl and ethyl methacrylate. Chain length of the polymer was modified by use of a transfer agent. The grana are composed of compartments consisting of electron-scattering partitions and electron-transparent loculi. Compartmen...

The methyl group of nicotine has been shown to participate in transmethylation reactions involving methionine (3) and choline (8). De novo synthesis of radioactive nicotine from nornicotine, methioninemethyl-C14 and ATP was demonstrated recently in leaves of Nicotiana alata (9). In the present study the rate of metabolism of the methyl group of nicotinemethyl-C14 ancl the rate of transmethylati...