This investigation examines responses of protoplasts in a systematic and quantitative way to the various electrical treatments used to achieve electrofusion and their individual and cumulative effect on protoplast viability. Mesophyll and cell suspension protoplasts from two species of the same genera, Nicotiana tabacum and N. rustica var brasilia were used in these experiments. Optimal frequen...

We have isolated and sequenced chloroplast (chl) and cytoplasmic (cyt) cysteine tRNAs from Nicotiana rustica. Both tRNAs carry a GCA anticodon but beyond that differ considerably in their nucleotide sequences. One obvious distinction resides in the presence of N6-isopentenyladenosine (i6A) and 1-methylguanosine (m1G) at position 37 in chl and cyt tRNA(Cys) respectively. In order to study the po...

Tobacco (Nicotiana rustica L. cv. Basmas) plants were exposed to a daily dose of 10 kJ m-1d-1 of UV radiation and treated with 0.5 mM exogenous polyamines (PAs) applied to the nutrient solution for two weeks. Dry weight of leaves increased under UVAB treatment in the absence of PAs and presence of spermidine but not putrescine. In the presence of putrescine, UVA treatment caused a significant i...

D-Glyceraldehyde-3J4C was synthesized and administered to intact Nicotiana rustica. Degradation of the pyridine moiety of nicotine produced by these plants showed that over half of the incorporated 1% was in position 4 of the pyridine ring, and the remainder of the radioactivity was divided almost equally among carbon atoms 2, 3, and 6. Lack of randomization of the label in positions 4, 5, and ...

Sexual adornments often vary markedly across a species’ range, which presumably is owing to differences in local environmental conditions and the associated selection pressures, such as natural versus sexual selection or the relative signaling value of different ornamental traits. However, there are only a few reported examples in which the information content of mating signals varies geographi...

Only two species of tobacco, Nicotiana tabacum L. and N. rustica L., have found an important place in cultivation for chewing or smoking purposes. N, rustica is now of little importance in agriculture, having been supplanted by AT', tabacum except in parts of Poland, Union of Soviet Socialist Republics, Asia Minor, and India. In both of these species the fundamental arrangement of the leaves al...