Inhibition of Membrane-Bound Adenosine Triphosphatase Activity from Nicotiana tabacum L. Leaves with Alkyltrimethylammonium Bromide

Cetyltrimethylammonium bromide (CTAB), a cationic detergent,more effectively inhibited the activity of membrane-bound epidermaladenosine triphosphatase (ATPase) of tobacco (Nicotiana tabacumL. cv. Samsun) leaves than anionic or non-ionic detergents.The inhibition of ATPase activity was highly dependent on thelength of the alkyl chain of alkyltrimethylammonium: CTAB >dodecyltrimethylammonium bromide > n-octyltrimethylammoniumbromide trimethylammonium chloride cetyl bromide, comparedat 10^–4 M. The last three derivatives hardly inhibitedthe activity. CTAB inhibition was equivalent to that due toother cationic detergents, cetylpyridinium bromide and cetylamine, but less than that by gramicidin S and tyrocidine andstronger than that by N,N'-dicyclohexylcarbodiimide and vanadate. These results show that a certain length of the alkyl chain(C_n>12) and the combination of both hydrophobic and chargedgroups of a detergent moiety are indispensable for inhibitingthe membrane-bound epidermal ATPase activity. (Received January 26, 1982; Accepted April 10, 1982)     

An Arabinogalactan-protein from the Leaves of Nicotiana tabacum

The signals of fatty acids in the form of triglycerides were observed in the ¹³C NMR spectrum of an intact soybean seed. The major fatty acid component composition of triglycerides in a soybean seed, which includes linoleic acid, oleic acid and palmitic acid, was estimated by subtracting the spectra of authentic fatty acids from the spectrum of the intact soybean seeds. The fatty acid compositions of seeds of 11 Japanese soybean cultivars and 5 lines bred at the Asian Vegetable Research and Development Center (AVRDC) were estimated by this rapid (within lhr for one seed) and nondestructive analytical method.     

Differential Ion Stimulation of Plasmalemma Adenosine Triphosphatase from Leaf Epidermis and Mesophyll of Nicotiana rustica L

An ATPase preparation, presumed to be associated with plasma membrane due to the coincidence on isopycnic gradients of cellulase and β-glucan synthetase at high substrate, has been isolated from the epidermal and mesophyll of tobacco leaf. The ATPase from both tissues was found to prefer ATP over other nucleotides. The pH optimum was 7.0 in the presence of 3 millimolar MgCl₂ and pH 6.5 in the presence of 3 millimolar MgCl₂ and 100 millimolar KCl. Monovalent ion stimulation patterns of the ATPases from these tissues were found to differ and ion accumulation patterns in these tissues reflect this difference: mesophyll accumulated roughly equal amounts of Na⁺ and Rb⁺ and its plasma membrane ATPase is also equally stimulated by these ions; on the other hand, epidermal ATPase preparations showed a stronger stimulation by Rb⁺ than Na⁺ and this tissue was found to accumulate Rb⁺ in preference to Na⁺. Abscisic acid and fusicoccin affected both ATPase activity and ion uptake, the former inhibiting and the latter stimulating these parameters. These data support the hypothesis that the epidermal plasmalemma ATPase is involved in stomatal opening.     

Rapid flowering Nicotiana tabacum L.

 Selected Nicotiana tabacum Tobacco Introductions from the Nicotiana Germplasm Collection were crossed, back-crossed, and then selfed. When compared to parents, the new genotypes produce smaller plants with a shortened life-cycle that go from seed to seed in under 11 weeks. Received: 11 December 1998 / Revision accepted: 8 January 1999     

Pectin Isolated from the Midrib of Leaves of Nicotiana tabacum

A pectin isolated from tobacco midrib contained residues of d-galacturonic acid (83.7%), L-rhamnose (2.2%), l-arabinose (2.4%) and d-galactose (11.2%) and small amounts of d-xylose and d-glucose. Methylation analysis of the pectin gave 2, 3, 5-tri- and 2, 3-di-O-methyl-l-arabinose, 3, 4-di- and 3-O-methyl-l-rhamnose and 2, 3, 6-tri-O-methyl-d-galactose. Reduction with lithium aluminum hydride of the permethylated pectin gave mainly 2, 3-di-O-methyl-d-galactose and the above methylated sugars. Partial acid hydrolysis gave homologous series of β-(1 → 4)-linked oligosaccharides up to pentaose of d-galactopyranosyl residues, and 2-O-(α-d-galactopyranosyluronic acid)-l-rhamnose, and di- and tri-saccharides of α-(1 → 4)-linked d-galactopyranosyluronic acid residues.

These results suggest that the tobacco pectin has a backbone consisting of α-(1 → 4)-linked d-galactopyranosyluronic acid residues which is interspersed with 2-linked l-rhamnopyranosyl residues. Some of the l-rhamnopyranosyl residues carry substituents on C-4. The pectin has long chain moieties of β-(1 → 4)-linked d-galactopyranosy] residues.     

Sperm dimorphism in Nicotiana tabacum L.

Sperm cells of tobacco have been intensively studied as examples of isomorphic gametes in which major cellular and organellar parameters remain statistically indistinguishable in the two sperm cells. An examination of sperm cells late in maturation, however, displays that the sperm cell associated with the vegetative nucleus becomes statistically significantly smaller than the other sperm cell in tobacco. If late divergence occurs in the two sperms of other angiosperms, sperm dimorphism may be more prevalent than has previously been assumed and dimorphism may have a major influence on the pattern of double fertilization. Received: 15 December 2000 / Accepted: 4 May 2001     

Galactan Isolated from the Midrib of the Leaves of Nicotiana tabacum

The structure of a galactan, obtained from the pectic polysaccharides of the midrib of the leaves of Nicotiana tabacum, was investigated by methylation analysis and partial acid hydrolysis. The galactan contained only d-galactose and was composed of a straight chain of β-(1→4)-linked d-galactopyranosyl residues.     

An Acidic Polysaccharide Isolated from the Midrib of Leaves of Nicotiana tabacum

An acidic polysaccharide (APS-H) purified from the hemicellulosic fraction of the midrib of Nicotiana tabacum was composed of d-galacturonic acid, l-rhamnose, l-arabinose and d-galactose in a molar ratio of 31.8: 15.4: 9.9: 42.9. Its molecular weight was estimated to be 90,000 by gel filtration chromatography. APS-H had a pectin-like structure in which the rhamnogalacturonan backbone was composed of (1 → 2)-linked l-rhamnopyranosyl and (1 → 4)-linked d-galacturonosyl residues in a ratio of approximately 1: 2.1. It also contained (1 → 4)-linked d-galactan and (1 → 5)-linked l-arabinofuranosyl moieties as the side chains. Branch points occurred mainly at C-4 of (1 → 2)-linked l-rhamnosyl residues in the backbone and at C-6 of (1 → 4)-linked d-galactosyl residues in the side chains.     

Biological effects of ion beams in Nicotiana tabacum L.

The biological effects of ion beams on Nicotiana tabacum L., particularly the induction of chromosome aberrations, were investigated. Dry seeds were exposed to ¹²C⁵⁺, ⁴He²⁺ and ¹H⁺ beams with linear energy transfer (LET) ranging from 1 to 111 keV/μm and irradiated with gamma-rays. Ion beams were more effective in reducing germination and survival of the seeds than gamma-rays. The LD₅₀ for ¹²C⁵⁺ beams, ⁴He²⁺ beams and gamma-rays were 35, 60 and 500 Gy, respectively. The frequencies of mitotic cells with chromosome aberrations, such as chromosome bridges, acentric fragments and lagging chromosomes in the root tip cells of the exposed seeds, increased linearly with increasing doses. Relative biological effectiveness (RBE) values, based on the doses that induced a survival inhibition of 50% and a 10% frequency of aberrant cells, were 14.3–17.5 for the ¹²C⁵⁺ beams, 7.0–8.3 for the ⁴He²⁺ beams and 7.8 for the ¹H⁺ beams. Furthermore, the relative ratios of the chromosome aberration types were significantly different between the ion beam and the gamma-ray regimes: chromosome fragments were more frequent in the former, and chromosome bridges in the latter. Based on these results, we concluded that the repair process of initial lesions induced by ion beams may be different from that induced by low- LET radiation. Received: 29 October 1998 / Accepted in revised form: 25 March 1999     

Influence of Iron Chlorosis on Pigment and Protein Metabolism in Leaves of Nicotiana tabacum L

Experiments were conducted on Nicotiana tabacum, L. to study the relation in the grana among chlorophylls, carotenoids, and proteins. The effect of iron chlorosis on protein and pigment synthesis was studied at different stages of chlorosis using glycine-U-C¹⁴. Pigments were separated by thin layer chromatography.

Chlorophyll a, chlorophyll b, carotenoid, and protein contents of chloroplasts from chlorotic tissue were less than those of normal tissues. A 25% decrease in protein labeling and a 45% decrease in chlorophyll labeling was noted in deficient tissue compared to normal tissue even before chlorosis was perceptible. Both normal and iron deficient leaf discs which received iron in the incubation medium incorporated higher amounts of radioactive glycine into chlorophyll a and chlorophyll b at all stages of development than their respective counterparts not supplied with iron in the incubation medium. The presence of iron in the incubation medium reduced the amount of glycine incorporated into carotenes and xanthophylls, except where the tissue was severely chlorotic. This may be attributed to active competition for glycine between the iron-dependent- (chlorophyll) and iron-independent-(carotenoid) biosynthetic pathways. Incorporation of glycine into chloroplast pigments was lowest at severe chlorosis, probably due to a reduction in the overall enzyme activity.

     

Developmental physiology of floral initiation in Nicotiana tabacum L.

The central process in the making of a multicellular organismis the fating of cells and tissues for their terminal phenotypes.The formation of a flower from a shoot apical meristem completesa sequence of fating processes initiated in embryogenesis. Thefating of a vegetative meristem of Nicotiana tabacum L. to initiatea flower involves at least two signals and two developmentalstates. A signal from the roots maintains vegetative growth,or prevents flowering, in the young seedling. As the plant grows,the vegetative meristem gains greater competence to respondto the floral stimulus from the leaves until it is evoked, byfloral stimulus, into a florally determined state. The florallydetermined state is then expressed. These developmental processesnot only establish the time of floral initiation, but also regulateplant size as measured by the number of nodes produced. Key words: Plant size, floral stimulus, competence, floral determination, induction     

Photosynthesis and Activity of Phosphoenolpyruvate carboxylase in Nicotiana tabacum L. Leaves Infected by Potato virus A and Potato virus Y

The influence of viral infection caused by two different potyviruses, Potato virus Y (PVY) and Potato virus A (PVA) on plant metabolism and photosynthetic apparatus of Nicotiana tabacum L. cv. Samsun and cv. Petit Havana SR1 was studied. The main stress was focused on the activities of phosphoenolpyruvate carboxylase (PEPC), NADP-malic enzyme (NADP-ME), and pyruvate phosphate dikinase (PPDK). The analysis of the presence of viral proteins, enzyme activities, and different photosynthetic parameters showed the time dependent progress of viral infection and NADP-ME and PEPC activities. PVY caused significant response, while PVA affected both tobacco cultivars only slightly. Viral infection, namely PVY, affected more negatively photosynthetic apparatus of cv. Petit Havana SR1 than cv. Samsun.     

Direct flower neoformation from superficial tissue of small explants of Nicotiana tabacum L.

Summary On explants composed of 3–6 layers of epidermal and sub-epidermal cells of Nicotiana tabacum L. from the floral branches, it is possible to obtain mitoses followed very rapidly by meioses and the direct formation of anthers and pistil without any intermediate callus.     

土壤pH值对烤烟叶片生理生化特性的影响

烟草生长初期,超氧化物歧化酶(SOD)活性及丙二醛(MDA)含量与pH增长呈正相关,而过氧化氢酶(CAT)和过氧化物酶(POD)活性则随着pH的增加而下降,pH值6.5和7.5时叶绿素含量和净光合速率(Pn)较高,旺长期达到高峰;生长后期,各处理的MDA含量和POD活性最高,SOD、CAT活性最低.各pH值处理的叶片中,叶绿素含量、Pn下降,比叶重达到高峰,但pH 8.5下的烟叶中叶绿素含量高,Pn大,比叶重较小.pH 6.5和7.5下的烟叶中蛋白质和可溶性糖总体含量高于其它pH的.烟碱含量在pH 5.5时最高,pH 8.5时最低.     

Genotypic control of pollen plant formation in Nicotiana tabacum L.

Summary Tobacco plants (Nicotiana tabacum L.) of four varieties (Badischer Burley, White Burley, Techne, Kupchunos) were raised at different temperatures and daylengths and the effect of genotype on embryogenic pollen grain formation in situ and on pollen plant formation in anther and pollen cultures from these plants was studied. Genotype controlled embryogenic pollen grain and pollen plant formation by defining productivity under standard growth conditions (long days at 24 °C). Kupchunos was the most productive variety, followed by White Burley, Techne, and Badischer Burley. Furthermore, genotype defined which environmental factor was able to affect embryogenic pollen grain and pollen plant formation and also to which degree. In anther cultures, in addition to these effects, genotype controlled the formation of (an) inhibitory substance(s) in the anther wall in interaction with the plant growth conditions. In Badischer Burley and Techne, inhibitor action could be prevented by isolation of the pollen after one week of anther culture. Finally, direct pollen cultures in Badischer Burley and Techne produced embryos were only when the pollen was isolated from nearly mature anthers, while in White Burley and Kupchunos, embryos also produced at earlier stages and at higher yields. This indicated that genotype controls the time when the embryogenic pollen grains become ready to divide. The results are discussed in relation to strategies to overcome recalcitrance of species and genotypes.     

Nicotiana tabacum DNA: Isolation from cell culture

The adaptation of Marmur’s method, suitable for DNA isolation from plant cell culture, is described.