Leaf Alkaloid Research Articles

The Reproductive Consequences Associated with Inducible Alkaloidal Responses in Wild Tobacco

We experimentally examined the phenotypic cost (as measured by the effect on seed set) associated with an inducible alkaloidal response in Nicotiana sylvestris (Solanaceae). Alkaloid concentrations were partially uncoupled from leaf damage in two experiments with the use of two techniques: (1) applying auxins to damaged leaf edges, and (2) minimizing the damage to veins of the leaf. Both of these techniques inhibited the induced response. In both experiments with flowering—stage plants, damaged plants with elevated alkaloids contents had lower reproductive output than similarly damaged plants with low alkaloid contents. Plants were able to compensate for damage inflicted during the rosette stage; reproductive output of damage plants did not differ from that of control plants. In addition, we found a significant negative correlation between seed number and leaf alkaloid content in undamaged full—sib plants. While these results are consistent with the hypothesis that the alkaloidal response to damage is associated with diminished reproductive output, and decrement in reproductive output cannot be directly attributed to alkaloid production because other unmeasured responses to damage may accompany the alkaloidal response to damage and thereby confound these measures of phenotypic cost. Last, we examined the consequences of altering leaf alkaloid concentrations, within the range found during the induced response, on rates of carbon gain and found no effect in tobacco.

Mechanism of damage-induced alkaloid production in wild tobacco

Greenhouse-grown tobacco plants of the speciesNicotiana sylvestris (Solanaceae) subjected to leaf damage show a fourfold increase in the alkaloid content of their undamaged leaves. This increase in nicotine and nornicotine concentrations begins 19 hr after the end of the damage regime, reaches a maximum at nine days, and wanes to control levels 14 days after the start of leaf damage. The increase in leaf alkaloid content in damaged plants is largely due to a 10-fold increase in the alkaloid concentration of the xylem fluid entering leaves, which, in turn, suggests that increased synthesis of alkaloids is occurring in the roots. This research distinguishes between positive and negative cues affecting the change in xylem fluid alkaloid concentrations. A negative cue, such as auxin, when lost or diminished as a result of leaf damage could signal the alkaloidal response. Indeed, exogenous applications of auxin to damaged leaves inhibit the alkaloidal response. However, attempts to block endogenous auxin transport by steam girdling or applying an auxin transport inhibitor fail to mimic the effect of leaf damage on leaf alkaloid concentrations. The damage cue appears to be a positive cue that is related to the timing and the amount of leaf damage rather than to the amount of leaf mass lost. Moreover, when performed proximally to leaf damage, steam girdling truncates the alkaloidal response. This induced alkaloidal response appears to be triggered by a phloem-borne cue that allows the plant to distinguish between different types of leaf damage. The physiological and ecological consequences of the mechanism of this damage-induced alkaloidal response are further explored.

Damage-induced alkaloids in tobacco: Pot-bound plants are not inducible

Field-grown wild tobacco plants (Nicotiana sylvestris) were subjected to a defoliation regime designed to mimic the rate and amount of leaf mass removed by one tobacco hornworm per plant. Undamaged leaves on these plants undergo a dramatic (457% for leaf position 5, 410% for leaf position 8) increase in total leaf alkaloids compared to same-age and positioned control leaves on undamaged control plants. However, potted greenhouse-grown plants fail to exhibit the same damage-induced increase in alkaloid content. The greenhouse environment differs from the field environment in factors known to influence leaf alkaloid content, particularly soil N, P, K, near-UV radiation, and relative humidity. However, altering these environmental factors does not make potted plants able to increase their leaf alkaloid levels in response to defoliation. Transplanting plants into larger pots with more soil does allow the plants to respond to defoliation. Thirty days after transplanting, the plants are again unresponsive to damage, probably as a result of becoming "pot-bound." This result suggests a mechanism for the induction response, specifically that leaf damage triggers synthesis of these alkaloids in the roots, and offers a potentially valuable experimental tool for the study of induced-plant defenses in tobacco and other plants that synthesize alkaloids in their root tissues.

Short-term damage-induced increases in tobacco alkaloids protect plants.

Leaf damage significantly increases the alkaloid content in undamaged leaves on damaged field-grown wild tobacco plants. Although field-grown pot-bound plants fail to exhibit the same damage-induced increase in alkaloid content, the ability to respond to leaf damage is restored 6 days after removing plants from their pots. Freshly hatched Manduca sexta larvae reared individually in the laboratory on the high-alkaloid foliage of damaged plants released from their pots gain less weight and eat less (57.2% and 45.7% of controls, respectively) than larvae fed low-alkaloid foliage from undamaged released plants. Moreover, larvae grow equally well on the foliage of damaged and undamaged pot-bound plants. The higher chlorophyll contents characteristic of damaged released plants did not negate the effects of the increased alkaloid contents on larval growth. Undamaged leaves from undamaged field-grown plants stem-fed nicotine solutions had elevated leaf nicotine and nornicotine contents. Larvae reared on these artificially induced leaves gain only 38.5% of the weight gained by larvae reared on low-alkaloid foliage. These results demonstrate that damage-induced increases in leaf alkaloids protect induced foliage from attack and are sufficient to explain the decreased growth of caterpillars on the foliage of damaged plants.

Variations in the Leaf Alkaloid Content of Androgenic Diploid Plants ofDatura innoxia

Anther culture of DATURA INNOXIA Mill, has permitted the obtention of spontaneous diploid androgenic plants which produced the tropane alkaloids. The source plants (zygotic diploid) showed no significant variations in the leaf alkaloid content. On the contrary, androgenic diploid plants obtained after the first cycle of androgenesis showed important quantitative and qualitative variations in the leaf alkaloid content. Thus, androgenesis was found to induce a large variation in the accumulation of these secondary metabolites in the leaves. It has also permitted the obtention of tropane alkaloid-overproductive plants, particularly rich in scopolamine. The analyses of zygotic plants obtained from seed germination of the first cycle androgenic plants have shown that this variability is transmissible by simple cross-pollination. The analyses of androgenic diploid plants obtained after the second cycle of androgenesis also showed variations in the leaf alkaloid content. IN VITRO androgenesis, therefore, clearly induced variability in the leaf alkaloid content of the androgenic plants. The role of IN VITRO androgenesis in inducing variability has been discussed.

Regulation of Product Synthesis in Cell Cultures ofCatharanthus roseus. III. Alkaloid Metabolism in Cultured Leaf Tissue and Primary Callus1

Cultured leaf discs of Catharanthus roseus produced visible callus under a variety of cultural conditions within 10 to 15 days. A peak of respiratory activity typical of rapidly growing callus was observed after 10-20 days culture. Photosynthesis was inactivated on transferring leaf tissue into culture within 5 days. During this period the two main leaf alkaloids, catharanthine and vindoline, were rapidly metabolised and were not found in primary callus or in the original leaf tissue after 40 days culture. The alkaloids serpentine and ajmalicine accumulated in leaf tissue but predominantly in callus, during the callus induction and growth period. Serpentine was the major alkaloid accumulated in the light and ajmalicine in the dark. Maximal alkaloid accumulation was found with the production media devised by Zenk but sustained callus growth did not occur. Cultures which accumulated high levels of serpentine over repeated subcultures were derived on other media, but these cultures did not contain catharanthine or vindoline.

Fertilizer Placement Effects on Growth, Yield, and Chemical Composition of Burley Tobacco1

AbstractApplication of high rates of commercial fertilizers to burley tobacco (Nicotiana tabacumL.) soils through commonly used broadcast methods increases the osmotic pressure of the soil solution and soil acidity. Such changes in the soil may result in damage to plant roots, nutrient toxicities and deficiencies, delayed growth and maturity, and reduced yields. The current study was conducted to determine the influence of placing N and K fertilizers in bands of varying width between rows on selected chemical characteristics of soil (Maury silt loam, clayey, mixed mesic, Typic Paleudalf) and on growth, yield, and chemical composition of burley tobacco, cv. Ky‐14. Field experiments were conducted during 1979 to 1980 at two locations. Treatments consisted of 840 kg NH4NO3ha−1and 672 kg K2SO4ha−1applied either broadcast or in bands 80, 60, 40, and 20 cm wide centered between rows. Plant samples were taken at 45 days, and after maturity and curing for growth, yield, and chemical analysis. Surface soil pH depression in the row decreased as distance of the fertilized band from the row increased and pH in rows of the 20 cm band treatment remained about 0.3 to 0.5 pH units higher throughout the season than in broadcast treatments. The reverse was true for soil pH in the fertilized bands, with the 20 cm band treatment having lowest pH. Placement of the fertilizer in bands away from the row resulted in decreased electrical conductivity of the soil solution in the row, in decreased DTPA‐extractable Mn in the row, lower concentration of plant Mn and K, and fewer days to flower. In contrast, banding increased plant dry weight (21 to 40%) and plant Mg concentration at 45 days, cured leaf yields (9%), value per ha, and cured leaf alkaloid concentration.

Lysine decarboxylase in plants and its integration in quinolizidine alkaloid biosynthesis

In leaves of alkaloid producing Lupinus polyphyllus lysine decarboxylase activity is positively correlated with the chlorophyll content during leaf regreening. A similar positive correlation was found between the leaf alkaloid content and lysine decarboxylase activity in L. albus and L. luteus. These results indicate that in lupin leaves lysine decarboxylase is an integrated part of the alkaloid specific biosynthetic sequence. Lysine decarboxylase could also be demonstrated in 46 alkaloidal and non-alkaloidal species out of 17 families of higher plants, including cell cultures of seven species.

Investigation of Cinchona leaf alkaloids by high-performance liquid chromatography

A high-performance liquid chromatographic (HPLC) system has been developed for the separation of thirteen Cinchona alkaloids. This system separates into two distinct groups the quinoline alkaloids, which are found predominantly in Cinchona bark, nd the indole alkaloids, which have been found to predominate in the leaves of one species. HPLC has been used to examine the alkaloid content of four plantation samples of Cinchona leaves obtained from different parts of the world. All four samples were found to contain different proportions of alkaloids and although the cinchophyllines were the major alkaloids found in two samples of Cinchona ledgeriana, quinoline alkaloids were also present. However, quinoline alkaloids were the major alkaloids of Cinchona succirubra from Thailand and C. succirubra × C.ledgeriana from Guatemala. In addition, quinamine and 3-epiquinamine were present in the four leaf samples investigated.

Antifungal stress metabolites from Solanum aviculare

The steroidal alkaloids 5β-solasodan-3-one and solasodenone were isolated as antifungal stress metabolites from leaves of Solanum aviculare stressed by vacuum infiltration with water. The constitutive leaf alkaloids, solasodine and solamargine, also showed antifungal activity.

Mammoth Genotypes and Tobacco Management Regimes for Reduced Production of Downstalk Tobaccos1

AbstractDemand for flue−cured tobacco (Nicotiana tabacum L.) from basal leaf positions has decreased in recent years, and production systems which maximize higher quality, upstalk, leaf grades are needed.In this study we tested production regimes utilizing photoperiod−sensitive genotypes to prevent flowering and produce additional upstalk leaves as a substitute for discarded basal leaves.Normal and photoperiod−sensitive (mammoth) versions of four cultivars were grown in field experiments at two locations in 2 years. Apical meristems of mammoth genotypes were removed when plants had produced the same number of leaves as normal cultivars, four leaves more than normal in 1977, and two leaves more than noma1 in 1978.Mammoth genotypes allowed to produce the same leaf number as normal cultivars provided higher yields, with leaf quality equal or superior to the controls. Total alkaloids were lower than in normal cultivars in 1977, but equal in 1978. Reducing sugar contents were equal in both types in 1977, but significantly higher for mammoths in 1978.Permitting mammoth plants to produce four more leaves than normal, with the bottom four leaves removed from the plants and discarded, resulted in yield overcompensation with slight reductions in leaf alkaloids and increases in reducing sugars. Two additional top leaves on mammoth entries did not compensate adequately for yield reductions caused by discarding the bottom four leaves. Leaf alkaloids and sugar contents in the latter production regime did not differ from those of control cultivars.These regimes could reduce the production of downstalk tobaccos without significant yield reductions and would eliminate all premature flowering. The maintenance of apical dominance in mammoths would enhance axillary bud control.

Berberine contents and alkaloid profile of Berberis species from different altitudes

Roots, stem and leaves of eight species of Berberis collected from different altitudes in Garhwal, Himilaya, were analysed for berberine. Lowland species and types were found to have considerably higher berberine contents in all plant parts than sub-alpine and alpine species. In all, 12 or more alkaloids were separable in these species. Based on the similarity coefficient of leaf alkaloids, B. nepalensis was found to be identical to B. asiatica and B. vulgaris was identical to B. lycium . It is suggested that the concentration of berberine is probably a result of adaptive response to altitudinal gradient in addition to it being a genetic character of different species of Berberis .

Constituents of Pachygone ovata and Pharmacological Action of its Major Leaf Alkaloid

Constituents of Pachygone ovata and Pharmacological Action of its Major Leaf Alkaloid

CORRELATION STUDIES AMONG AND BETWEEN AGRONOMIC, CHEMICAL, PHYSICAL AND SMOKE CHARACTERISTICS IN FLUE-CURED TOBACCO (NICOTIANA TABACUM L.)

Coefficients of correlation among 23 characteristics were determined for several flue-cured tobacco (Nicotiana tabacum L.) cultivars and advanced generation breeding lines, representing a wide range of variability for each characteristic. The variables were grouped into agronomic, chemical and physical characteristics of the leaf and smoke properties of cigarettes. Most of the traits studied in these individual groups could be classed into two main categories in terms of their relationship to yield, leaf alkaloids, smoke total particulate matter (TPM) and wet tar (WT). Those agronomic characteristics positively associated with yield were negatively correlated with leaf total alkaloids, lamina weight and smoke TPM, WT and alkaloids on a per cigarette basis. Conversely, grade index and the average length of the three top leaves, which were in negative association with yield, showed a positive relationship with leaf total alkaloids and smoke characteristics. Leaf total alkaloids and lamina weight, in positive association with each other, were positively correlated with smoke TPM, WT, and alkaloids. However, both of these traits were negatively correlated with yield.

Leaf alkaloids of Fagara mayu

Leaf alkaloids of Fagara mayu

Varietal Response of Burley Tobacco to Stage of Physiological Development when Topped1

AbstractLittle is known about the effects of stage of physiological development at which the plants are topped on early vs. late flowering cultivars of burley tobacco (Nicotiana tabacum L.). Four cultivars with a range of 18 days in flowering were topped at different stages of development to determine the optimum topping date for specific cultivats, whether discrimination would exist if all cultivars were topped simultaneously, and whether or not it would be feasible to use an extremely late‐flowering cultivar commercially.Topping ‘MS Burley 37 × LS’ or ‘Burley 37’ earlier than full bloom, ‘Burley 49’ later than 50% bloom, or ‘Burley 64’ later than button stage did not increase yield significantly. Percent total N and percent total alkaloids in leaf from plots of the respective cultivars topped at these stages were within normally accepted ranges. Thus, all entries in a variety trial may be topped at the same time without creating undue bias of the estimates obtained. Maximum performance of Burley 64 was obtained when it was topped in the button stage. This indicates that a late flowering cultivar may be grown commercially if it is topped at an earlier stage of development but about the same date as early flowering cultivars.

RESPONSE OF CIGAR TOBACCO TO DIFFERENT DATES OF PLANTING AND SPACING

Response of cigar tobacco (Nicotiana tabacum L.) in morphological, agronomic and chemical characteristics to date of planting and planting distance was studied during 1971–73. A cultivar and a breeding line of cigar tobacco were transplanted outdoors on 26 May, 9 (or 12) June and 23 June. The tobacco was spaced 36, 41 and 46 cm in rows that were 97 cm apart. The best results were obtained when cigar tobacco was transplanted not later than 9 June, and the plants were spaced 41 cm in the rows that were 97 cm apart. The highest number of leaves per plant, cured-leaf yield, percentage of nicotine and total alkaloids were obtained from the tobacco transplanted on the first or second date in 3 yr. In 2 yr, the later tobacco had the tallest plants, the largest leaves, the highest percent filler leaf, grade and crop index. Earlier-transplanted tobacco was harvested earlier, although the period to flower decreased with later date of planting. On the average, the tobacco spaced 41 cm was taller and had a shorter period to flower, and higher yield and crop index than that spaced 36 cm or 46 cm. Grade index, percent filler leaf, nicotine and total alkaloids were affected significantly by the distance in 1 yr only.

Biological and Phytochemical Evaluation of Plants XI: Isolation of Aspidospermine, Quebrachidine, Rhazinilam, (—)-Pyrifolidine, and Akuammidine from Aspidosperma Quebracho-blanco (Apocynaceae)

A phytochemical investigation of the leaves of Aspidosperma quebracho-blanco (Apocynaceae) resulted in the isolation of rhazinilam, a new nonindole lactam alkaloid, in addition to the known bases, aspidospermine, quebrachidine, (—)-pyrifolidine, and akuammidine. Aspidospermine and quebrachidine were the major leaf alkaloids. Akuammidine and (—)-pyrifolidine were isolated from the leaves for the first time, and the isolation of the latter compound confirms its natural occurrence in this plant.

Elaeocarpus Alkaloids. V. The Alkaloids of Elaeocarpus kaniensis

The leaf alkaloids of Elaeocarpus kalziensis Schltr. are a complex mixture, from which eight new alkaloids have been separated. Spectroscopic evidence has shown that these alkaloids are a closely interrelated group of indolizidines and structures have been assigned to elaeokanine A (1), elaeokanine B (8), elaeokanine C (10), elaeokanine D (12), elaeokanine E (17), and elaeokanidine A (18), Elaeokanidine B and elaeokanidine C are stereoisomers of elaeokanidine A, but the spectroscopic evidence is insufficient for the structures of these alkaloids to be assigned unequivocally. The assigned structures in all cases indicate relative and not absolute stereochemistry. The structures established for elaeokanine A, elaeokanine B, and elaeokanine C by spectroscopic methods have been confirmed by synthesis. Catalytic hydrogenation of synthetic 8-n-butyryl-7-oxoindolizidine (22) over platinum oxide in ethanol afforded (�)elaeokanine C in 30% yield. Under these hydrogenation conditions a major product was 8-n-butyryl-7-oxo-8,9-dehydroindolizidine (23) formed by loss of hydrogen from (22).

The alkaloidal pattern in the leaves, stem-bark and root-bark of Mitragyna species from Ghana.

Abstract The leaves, stem-bark and root-bark of Mitragyna ciliata, M. inermis and M. stipulosa have been examined quantitatively and qualitatively for alkaloids. In addition, the plant parts of M. stipulosa collected at 12 regular monthly intervals have been similarly examined. The presence of mitraphylline in the leaves of this plant and the absence of indole alkaloids was confirmed. The predominant leaf alkaloids are oxindoles of the A series, those of the stem- and root-bark, oxindoles of the B series. Whereas the general alkaloidal pattern of M. ciliata appears similar to that of M. inermis rather than M. stipulosa, a more detailed study suggests that M. ciliata and M. inermis have a distinctly different metabolic pattern in relation to the C(9)-OMe alkaloids.