Total Phenolic Production Research Articles

Pepper plants growth, yield, photosynthetic pigments, and total phenols as affected by foliar application of potassium under different salinity irrigation water

Irrigation with high salinity water influences plant growth, production of photosynthetic pigments and total phenols, leading to reduction in crop yield and quality. The objective of this study was to investigate the effects of potassium (K) foliar application in mitigating the negative effects of salt stress on pepper plants. A greenhouse experiment was conducted to investigate the effects of foliar application of potassium (K) on pepper plants grown with different salinity water irrigation (3000 and 6000 ppm as compared to tap water with salinity level of 300 ppm). Irrigation using high salinity water decreased plant height, biomass production, and fruit yield as compared to those of the plants irrigated by tap water. Photosynthetic pigments and total phenols increased in the former as compared to those of the latter plants. The most serious affect was for the plants under highest salinity irrigation (6000 ppm) as compared to that of the plants under moderate salinity irrigation (3000 ppm). Foliar application of potassium mono phosphate (KMP) at 200ppm concentration increased the plant growth, biomass production, and fruit yield. Chlorophyll_a content and total phenols increased significantly with foliar application of 100 ppm KMP. Further increase in foliar KMP concentration to 200 ppm had no significant benefits on photosynthetic pigments and total phenols content. This study demonstrated that foliar application of KMP, to some extent, mitigated the negative effects of high salinity water irrigation on pepper plant growth and fruit yield.

Genetic effects on total phenolics, condensed tannins and non-structural carbohydrates in loblolly pine (Pinus taeda L.) needles

Carbon allocation to soluble phenolics (total phenolics, proanthocyanidins (PA)) and total non-structural carbohydrates (TNC; starch and soluble sugars) in needles of widely planted, highly productive loblolly pine (Pinus taeda L.) genotypes could impact stand resistance to herbivory, and biogeochemical cycling in the southeastern USA. However, genetic and growth-related effects on loblolly pine needle chemistry are not well characterized. Therefore, we investigated genetic and growth-related effects on foliar concentrations of total phenolics, PA and TNC in two different field studies. The first study contained nine different genotypes representing a range of genetic homogeneity, growing in a 2-year-old plantation on the coastal plain of North Carolina (NC), USA. The second study contained eight clones with different growth potentials planted in a 9-year-old clonal trial replicated at two sites (Georgia (GA) and South Carolina (SC), USA). In the first study (NC), we found no genetic effects on total phenolics, PA and TNC, and there was no relationship between genotype size and foliar biochemistry. In the second study, there were no differences in height growth between sites, but the SC site showed greater diameter (diameter at breast height (DBH)) and volume, most likely due to greater tree mortality (lower stocking) which reduced competition for resources and increased growth of remaining trees. We found a significant site × clone effect for total phenolics with lower productivity clones showing 27-30% higher total phenolic concentrations at the GA site where DBH and volume were lower. In contrast to the predictions of growth-defense theory, clone volume was positively associated with total phenolic concentrations at the higher volume SC site, and PA concentrations at the lower volume GA site. Overall, we found no evidence of a trade-off between genotype size and defense, and genetic potential for improved growth may include increased allocation to some secondary metabolites. These results imply that deployment of more productive loblolly pine genotypes will not reduce stand resistance to herbivory, but increased production of total phenolics and PA associated with higher genotype growth potential could reduce litter decomposition rates and therefore, nutrient availability.

Increased carbon dioxide concentration improves the antioxidative properties of the Malaysian herb kacip fatimah (Labisia pumila Blume).

A randomized complete randomized design (RCBD) 3 by 3 experiment was designed to investigate and distinguish the relationships among production of secondary metabolites (total phenolics, TP; total flavonoids, TF), gluthatione (GSH), oxidized gluthatione (GSSG), soluble carbohydrate and antioxidant activities of the Malaysian medicinal herb Labisia pumila Blume under three levels of CO2 enrichment (400, 800 and 1,200 µmol mol−1) for 15 weeks. It was found that the treatment effects were solely contributed by interaction of CO2 levels and secondary metabolites distribution in plant parts, GSH, GSHH and antioxidant activities (peroxyl radicals (ROO), superoxide radicals (O2), hydrogen peroxide (H2O2) and hydroxyl radicals (OH). The records of secondary metabolites, glutahione, oxidized gluthathione and antioxidant activities in a descending manner came from the leaf enriched with 1,200 µmol/mol CO2 > leaf 800 µmol/mol CO2 > leaf 400 µmol/mol CO2 > stem 1,200 µmol/mol CO2 > stem 800 µmol/mol CO2 > stem 400 µmol/mol CO2 > root 1,200 µmol/mol CO2 > root 800 µmol/mol CO2 > root 400 µmol/mol CO2. Correlation analyses revealed strong significant positive coefficients of antioxidant activities with total phenolics, flavonoids, GSH and GSHH indicating that an increase in antioxidative activity of L. pumila under elevated CO2 might be up-regulated by the increase in production of total phenolics, total flavonoids, GSH, GSHH and soluble sugar. This study implied that the medicinal potential of herbal plant such as L. pumila can be enhanced under elevated CO2, which had simultaneously improved the antioxidative activity that indicated by the high oxygen radical absorbance activity against ROO, O2, H2O2, and OH radicals.

Bioactivity of wine prepared from ripened and over-ripened kiwifruit

Abstract In order to evaluate the fruit maturity value of ‘Hayward’ kiwifruit (Actinidia deliciosa) as material for wine production, ripened and over-ripened fruit samples were analyzed. In addition, the effect of pectinase enzyme treatment on physicochemical characteristics of the wine during the fermentation process was also examined. The results showed that wine production from ripening kiwifruit took almost twice as long as from over-ripened fruit. The yield of wine production was increased from 63.35% to 66.19% by using riper kiwifruits and adding pectinase before amelioration. The soluble solid content (13.5%) in the wine produced from over-ripened fruits increased in comparison with the wine produced from ripened samples (10.3%). In both groups there was a decrease to 5° Brix at the end of fermentation. Difference of fruit maturity did not have a significant effect on acidy, pH, nor color of wine. The highest scores of total acceptance estimated during fermentation were for wine made from over-ripened fruits. Total phenolics content and antioxidant activities were similar in both wine groups while the mineral content, especially potassium, in wine made from over-ripened kiwifruit was higher than wine produced from ripened fruits. In conclusion, the quality characteristics of kiwifruit wine made from over-ripened fruit treated with pectinase showed higher values of wine in many aspects such as sensory value, alcohol and total phenolics content, antioxidant activity, minerals and production yield.

In situ phenol removal from fed-batch fermentations of solvent tolerant Pseudomonas putida S12 by pertraction

In situ phenol pertraction with 1-octanol has been experimentally studied to improve the production of the model component phenol by a recombinant strain of Pseudomonas putida S12. When the phenol concentration in the reactor reaches 2mM, the cells in fermentations without phenol removal are inhibited in growth and phenol production. Growth and phenol production stop after approximately 80h at a phenol concentration in the reactor of 3.8mM. When phenol is removed from the fermentation broth by pertraction, a lower maximum aqueous phenol concentration of 2.6mM is achieved, while the total phenol production increases to 132%, as compared to the fermentation without pertraction. There are indications that the volumetric productivity (mmolL−1h−1) increases slightly in the fermentations with in situ pertraction compared to the reference experiments. As expected, the amount of phenol produced per gram biomass (the specific productivity, mmolg−1L−1) remains constant in time for all fermentations. The use of pertraction for in situ phenol removal is compared to in situ second phase extraction, in situ solvent impregnated resins and in-stream pertraction. Although the system shows promising results, further modifications such as using a solvent with a higher partition coefficient can improve the overall performance.

Effect of different light intensities on total phenolics and flavonoids synthesis and anti-oxidant activities in young ginger varieties (Zingiber officinale Roscoe).

Nowadays, phytochemicals and antioxidants in plants are raising interest in consumers for their roles in the maintenance of human health. Phenolics and flavonoids are known for their health-promoting properties due to protective effects against cardiovascular disease, cancers and other disease. Ginger (Zingiber officinale) is one of the traditional folk medicinal plants and it is widely used in cooking in Malaysia. In this study, four levels of glasshouse light intensities (310, 460, 630 and 790 μmol m−2s−1) were used in order to consider the effect of light intensity on the production, accumulation and partitioning of total phenolics (TP), total flavonoids (TF) and antioxidant activities in two varieties of Malaysian young ginger (Zingiber officinale). TF biosynthesis was highest in the Halia Bara variety under 310 μmol m−2s−1 and TP was high in this variety under a light intensity of 790 μmol m−2s−1. The highest amount of these components accumulated in the leaves and after that in the rhizomes. Also, antioxidant activities determined by the 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) assay in both of varieties, increased significantly (p ≤ 0.01) with increasing TF concentration, and high antioxidant activity was observed in the leaves of Halia Bara grown under 310 μmol m−2s−1. The ferric reducing (FRAP) activity of the rhizomes was higher than that of the leaves in 310 μmol m−2s−1 of sun light. This study indicates the ability of different light intensities to enhance the medicinal components and antioxidant activities of the leaves and young rhizomes of Zingiber officinale varieties. Additionally, this study also validated their medicinal potential based on TF and TP contents.

Linoleic and α-linolenic fatty acids affect biomass and secondary metabolite production and nutritive properties of Panax ginseng adventitious roots cultured in bioreactors

The effect of elicitation with linoleic (C18:2) and α-linolenic (C18:3) fatty acids (LLA and α-LNA) was investigated in Panax ginseng C.A. Meyer adventitious roots cultured in 5 l balloon-type bioreactors. Fatty acids were added in culture medium at 0.0, 1.0, 2.5, 5.0, 10.0, and 20.0 μmol l −1 at day 40, at the end of exponential growth phase. Roots were harvested and assayed at day 47. Elicitation with both LLA and α-LNA enhanced accumulation of total polyphenolics and flavonoids in roots compared with control without elicitation. The highest accumulation of flavonoids was observed at 5.0 μmol l −1 for both elicitors. Total phenolics production reached its highest value of about 4.0 mg g −1 DW under the elicitation with 5.0 μmol l −1 LLA and 5.0–20.0 μmol l −1 α-LNA. Meanwhile, α-LNA was more effective than LLA for increasing biomass and ginsenoside production. The biomass of 11.1 g DW l −1 and maximal total ginsenoside content of 7.9 mg g −1 DW were achieved at 5 μmol l −1 α-linolenic acid. The essential polyunsaturated linoleic (C18:2) and α-linolenic (C18:3) fatty acids were accumulated in roots in response to elicitation while content of palmitic (C16:0) and oleic (C18:1) acids declined. The activities of SOD, G-POD and CAT were enhanced by two elicitors to similar extent while APX activity was preferably stimulated by α-LNA. Our results demonstrate that elicitation with α-linolenic acid stimulates production of biomass and secondary metabolites in bioreactor-cultured P. ginseng adventitious roots.

Optimisation of antioxidants extraction from soybeans fermented by Aspergillus oryzae

The extraction of antioxidant compounds from soybeans fermented with Aspergillus oryzae was optimised using a factorial design. A kinetic study of the total phenolic production and DPPH radical scavenging activity was first performed at the points selected in the factorial design. In both cases, the experimental profiles were fitted to a modified first-order kinetic model. To investigate the combined effects of temperature and solvent concentration on the extraction, the parameters obtained from the fitted kinetic models were used as response variables in a rotatable second-order design with quintuple replications in the centre of the experimental domain. The results obtained indicate that temperature had the most significant effect. The response surfaces show a maximum in the experimental domain studied. The optimum conditions for the extraction of total phenolic content were 65.3 °C and 73.1% ethanol, in which 56.2 mg of GAE/g were predicted. A scavenging activity of 81.6% DPPH radical was predicted at the optimum conditions of 61.6 °C and 60% ethanol.

Production of phenolic compounds from Spirulina maxima microalgae and its protective effects

The purpose of this study was to illustrate the enhancing process of phenolics synthesis in Spirulina maxima grown in Zarrouk’s medium supplemented with different concentration of NaNO3 and/or combined with phenylalanine (L-PA). Also, the protective efficacy of Spirulina polyphenolic (SPP) extracts against CCI4-induced microsomal lipid peroxidation and scavenging of hydroxyl radical formation were performed. The results revealed that the levels of NaNO3 and L-PA in growth medium had positive effects on the production of biomass (34-64 mg/day), total phenolics (4.51-16.96 mg/g d.w) and flavonoids (1.32-5.12 mg/g d.w) contents. The highest levels of these compounds were obtained in Zarrouk’s medium containing 3.77 g/L NaNO3 and 100 mg/L L-PA. The HPLC-DAD profile of all phenolic extracts of Spirulina showed the presence of large numbers of phenolic acids and flavonoids, in variable levels. Gallic, chlorogenic, cinnamic, pinostrobin and p-OH-benzoic were found as the most abundant constituents among different extracts. Polyphenolic of Spirulina exhibited antioxidant effects CCI4-induced lipid peroxidation (inhibition %) in liver homogenate and on DPPH radical scavenging activity (with IC50 values ranged from 23.22 to 35.62 ig/ml), in dose-depended manner. Their protective potential was comparable to that of standard phenolic antioxidants (BHT, BHA and
-tocopherol, with IC50 values ranged from 13.22 to 23.62 ig/ml). Thus, S. maxima can be regarded as potent natural sources of nutraceutical and functional ingredients.

Relationships among the Contents of Total Phenolics, Soluble Carbohydrate, and Free Amino Acids of 15 Aquatic Macrophytes

ABSTRACT In order to examine how carbon and nitrogen status of a macrophyte may affect its total phenolics (TP) production, the contents of free amino acids (FAA), soluble carbohydrate (SC) and TP were examined in leaves of seven submersed, four floating-leaved, and four emergent macrophytes. The floating-leaved and emergent macrophytes had much higher contents of SC and TP than the submersed macrophytes. The contents of FAA were not significantly different among the submersed, floating-leaved, and emergent macrophytes. Correlations among the contents of FAA, SC, and TP indicated that the production of TP was more dependent on the SC content than on the FAA content.

Production of Iridoids and Phenolics by Transformed Harpagophytum procumbens Root Cultures

AbstractHarpagophytum procumbens (Devil's claw) is an important medicinal plant, which tubers are used for the treatment of different inflammatory diseases. In this study, the time courses of growth of Devil's claw hairy roots and accumulation of intracellular total iridoids and phenolics were investigated during cultivation under submerged conditions. After 21 days of growth in liquid hormone‐free MS medium, a growth index of 81.3 was achieved and the accumulated biomass reached 0.58 g/flask. It was found that the time courses of total iridoids and phenolics production showed almost the same patterns with a maximum on day 21 from the beginning of cultivation (15.93 mg harpagoside equivalents/L and 261 mg gallic acid equivalents/L, respectively). The methanolic extracts possessed relatively high DPPH‐radical scavenging properties (IC50 4.08 mg/mL), while for the culture media no antiradical activity was detected. According to our best knowledge, the present report is the first one dealing with the investigation of transformed root cultures from Harpagophytum procumbens plants.

Induced responses in three tropical dry forest plant species – direct and indirect effects on herbivory

Induced changes in plant quality are hypothesized to reduce herbivore numbers and subsequent damage to the plant. The resultant decrease in herbivory may be due to direct negative impacts on herbivores, through the reduction in foliage quality as food, or due to indirect effects of plant‐induced traits interacting with the third trophic level, increasing predation and parasitism rates on herbivores. The relative importance of induced responses as direct and/or indirect defenses has not been evaluated in natural systems. Moreover, few studies have evaluated the influence of early‐season damage on late‐season herbivory in natural systems, particularly in the tropics. The presence of induced responses and subsequent impact on folivory as a consequence of early‐season damage were evaluated in three plant species (Croton pseudoniveus, Bursera instabilis and Piper stipulaceum) in a tropical dry forest in Mexico. A two‐factorial experiment was applied to determine if induced responses influenced subsequent herbivory directly, by reducing foliage quality, or indirectly, through their interaction with parasitoids and predatory arthropods. Plants from all three species with reduced early‐season damage had higher herbivory rates through the rest of the growing season, compared to plants that were damaged during leaf expansion. Chemical analyses showed that early‐season damage induced the production of total phenolics and condensed tannins for C. pseudoniveus and B. instabilis, respectively. The mechanism by which these compounds affected subsequent herbivory was most likely by directly reducing foliage quality as food for herbivores, given that predatory arthropods and parasitoids had no effects on herbivory in this study. I conclude that early‐season damage in these three species influenced later‐season herbivory through the induction of plant responses that may act to reduce plant quality as food for herbivores.

Phenolic constituents and antioxidant capacities of Crataegus monogyna (Hawthorn) callus extracts.

Crataegus (Hawthorn) has long been used as a folk medicine and is widely utilized in pharmaceutical preparations mainly because of its neuro- and cardiosedative actions and its low toxicity. The pharmacological effects of Crataegus have mainly been attributed to the polyphenolic contents. In this study, the production of polyphenols by ten-year-old Crataegus monogyna calli was studied in relation to growth variation and antioxidant capacity within a subculture period. Assays based on the Trolox equivalent antioxidant capacity (TEAC), ferric reducing antioxidant power (FRAP) and stability in oil-in-water emulsion were used to characterize the antioxidant actions of the callus cultures. High TEAC (3.66 micromol/g dry weight) and FRAP (208.19 micromol Fe2+/g dry weight) values were observed when maximal growth was reached(days 30-35), and this seemed to be influenced by optimum total phenol (47.40 mg/g dry weight), proanthocyanidin (20.81 mg/g dry weight), flavonoid (7.01 mg/g dry weight), anthocyanin (6.18 mg/g dry weight), (-)-epicatechin (1.77 mgl/g dry weight), procyanidin B2 (3.97 mg/g dry weight), and chlorogenic acid (1.11 mg/g dry weight) production during that period. The TEAC values were strongly associated with total flavonoids and to a lesser extent with total phenols, anthocyanins and total proanthocyanidins. The FRAP antioxidant values correlated to total phenols, proanthocyanidins and flavonoids, respectively. The polyphenolic rich calli were as effective as butylated hydroxytoluene (BHT) in preventing hydroperoxide and conjugated diene formation in a 30% oil-in-water emulsion prepared with stripped sunflower oil, during 7days storage at 30 degrees C. Crataegus monogyna cell culture represents an important alternative source for natural antioxidants.

Light-mediated fava bean ( Vicia faba) response to phytochemical and protein elicitors and consequences on nutraceutical enhancement and seed vigour

Fava bean seedlings are a rich source of levo dihydroxy phenylalanine ( l-DOPA), the precursor of the neurotransmitter dopamine. The nutraceutical value and seed vigour of light germinated fava bean seedlings were significantly improved by priming with natural elicitors like fish protein hydrolysates (FPH), lactoferrin (LF) and oregano extract (OE). These elicitors stimulate the phenylpropanoid pathway through the pentose phosphate and shikimate pathway enhancing the production of total phenolics and seed vigour. Previous research in our laboratory has shown that the best elicitor concentration for fava bean was 2 ml/l FPH, 50 ppm LF and 5 ml/l of OE. A 100% germination rate was observed in seeds primed with FPH, 97% with OE, and 92% in LF primed and control. Priming with FPH improved growth by 35 and 25.5% by OE when compared to control. The seeds primed with LF showed no significant increase compared to the control. A significant boost in total phenolics was seen in primed seedlings and this correlated with enhanced seedling height and weight. On day 16 the total phenolics was 25, 9 and 17% higher in FPH, LF and OE primed, respectively, when compared to control. On all days measured the G6PDH activity was higher in control than the elicited seedlings. Previous experiments have shown that for all elicitor treatments a high G6PDH activity was recorded during early germination (24 h) with a concurrent increase in total phenolics and was then reduced by day 20. In the case of control seedlings, phenolics and G6PDH activity was highest on day 20 corresponding to potential delayed developmental demand for metabolites. A steady increase in the GPX activity was observed as the germination progressed both in the case of control and primed seedlings reflecting the plants need for phenolics for lignification and structural development during growth. The antioxidant activity was maximal on day 20 for all treatments demonstrating that perhaps polymerization of phenolics has an antioxidant enhancing effect. The l-DOPA content in fava bean primed with FPH showed a 120% increase over that of the control, corresponding with the high phenolic production on day 16. The elicitors LH and OE showed a 97 and 30% increase respectively over that of the control. The present study demonstrates that elicited fava bean seedlings containing enhanced levels of l-DOPA has excellent potential for use as a functional food, nutraceutical and as an antioxidant. This research also holds agronomic importance suggesting the use of FPH and OE as elicitors to improve fava bean seed vigour and plant productivity.

Phenolic antioxidant compounds produced by in vitro shoots of sage ( Salvia officinalis L.)

In vitro shoots of sage ( Salvia officinalis L.) were established under four different cytokinin supplementations by culturing nodal segments excised from aseptically germinated seedlings. The highest rates of shoot proliferation and linear shoot growth occurred with the supplementation of 1.5 mg/l benzyladenine and 0.05 mg/l dichlorophenoxyacetic acid. However, under these conditions, the specific production of total antioxidant phenolics was the lowest. Variation in kinetin (KIN) concentration (1.5; 2.0; 4.0 mg/l), in the presence of 0.05 mg/l 2,4-D, did not influence significantly the rates of shoot proliferation and linear shoot growth but influenced the production of antioxidant phenolics and biomass. Seventeen compounds were identified in the antioxidant phenolic extracts from shoots: gallic acid, 3- O-caffeoylquinic acid, 5- O-caffeoylquinic acid, caffeic acid, and rosmarinic acid, as phenolic acids; hesperetin, apigenin, hispidulin, cirsimaritin, and genkwanin, as flavonoids; epirosmanol, epirosmanol methyl ether, carnosol, epiisorosmanol ethyl ether, rosmadial, carnosic acid, and methyl carnosate, as phenolic diterpenes. With exception of carnosic acid and methyl carnosate, all the other phenolic compounds (15) were also identified in a commercial sample of this species. Rosmarinic acid and carnosol were the main compounds in all the antioxidant phenolic extracts. The increase in concentration of KIN decreased the accumulation of the most of phenolic diterpenes, particularly that of carnosol.

The influence of drought, shade and availability of mineral nutrients on exudate phenolics of Dittrichia viscosa

Summary Exudate phenolics are thought to defend leaf surfaces against microorganisms and interfere with neighboring plants if leached to the soil. We investigated the effects of resource availability on growth and accumulation of epicuticular water soluble phenolics in potted seedlings of Dittrichia viscosa grown in the field under two levels of nutrients, water and photon fluence rates. As expected, growth was enhanced under additional nutrients and suppressed under water stress. Under shade, aboveground biomass accumulation was not affected, yet the total leaf area was considerably increased at the expense of dry mass invested on area basis. Glandular hair density was not affected by any treatment. The concentration of leaf exudate phenolics was increased under water stress and decreased under additional nutrients and shade, in accordance to the prevailing hypotheses predicting environmental effects oncarbon-based defensive secondary metabolites. Yet, when we considered total epicuticular phenolic production on a plant basis (i.e. the amount leachable to the soil, which better indicates its allelopathic potential), the changes in total leaf area compensated (shade) or over-compensated(nutrients, water stress) the changes in concentration. Thus, total leachable epicuticular phenolics were higher under additional nutrients and lower under water stress. We conclude that environmental factors and the corresponding physiological constrains in the production of exudate phenolics may act in opposite directions when surface protection and interference with neighbors is considered.

Establishment and growth characteristics of Glycyrrhiza glabra hairy root cultures

Hairy root cultures of Glycyrrhiza glabra producing considerable amounts of phenolic compounds were successfully established by using Agrobacterium strain C58C18(pRT GUS 104). The effect of phosphate, ammonia, nitrate and ferric-EDTA concentrations of culture medium on growth and total phenolics production of the cultures were studied. By employing statistical experimental design and linear regression analysis an improved B5 medium (B50-M) could be developed. When cultivating G. glabra hairy roots in B50-M medium we were able to obtain 9 g dried roots/l in 25 days which was twice as much as when using the initial B50 medium. According to tentative analyses the cultures did not contain glycyrrhyzin, but they produced liquiritigenin and isoliquiritigenin. The production of total phenolic substances (mg g-1 dw) was higher in the improved medium resulting in significantly higher volumetric productivity (mg phenolic compounds l-1). This will further enable the extraction and identification of the phenolic compounds produced by the cultures.

Effect of nitrogen fertilization on leaf phenolic production of grand fir seedlings

A significant decrease in production of total phenolics was apparent with nitrogen fertilization in three of five seed sources of grand fir [Abies grandis (Dougl.) Lindl.]. Subsequent extraction and identification of phenolics indicated that two compounds increased with fertilization, and when grouped by biosynthetic origin into cinnamic acids, benzoic acids, and flavonoids, no differences were apparent with fertilization. Total biomass increased with fertilization, and the relation between growth and total phenolics was similar for all seed sources. The increase in growth and decrease in total phenolics suggest that, in the carbon allocation hierarchy, as available soil nitrogen increases, phenolics represent a lower priority.

Application of a new structured model to tobacco cell cultures

A new structured kinetic model has been formulated and applied to batch suspensions of Nicotiana tabacum. This model has been developed by representing culture interactions with pathways designated for structural component production, secondary metabolite synthesis, and cellular respiration. Additional provisions were made to distinguish growth-competitive secondary metabolite production from non-growth-competitive secondary metabolite production. Parameters for kinetic rate expressions within the model were estimated based upon experimental observations utilized in conjunction with numerical optimization techniques. Using these parameters, culture growth, substrate uptake, cell respiration, and total phenolics production were all successfully correlated to experimental data from shake flask cultures of N. tabacum.