Studies on the Production of Digitalis Cardenolides by Plant Tissue Culture: II. EFFECT OF LIGHT AND PLANT GROWTH SUBSTANCES ON DIGITOXIN FORMATION BY UNDIFFERENTIATED CELLS AND SHOOT-FORMING CULTURES OF DIGITALIS PURPUREA L. GROWN IN LIQUID MEDIA

Undifferentiated, highly chlorophyllous cell cultures; undifferentiated white cell cultures; green, shoot-forming cultures; and white, shoot-forming cultures of Digitalis purpurea L. were established and subcultured every 3 weeks in liquid media in the light or in the dark. The digitoxin content, the chlorophyll content, and the ribulose bisphosphate carboxylase activity of these cultures were assayed. The light-grown, green, shoot-forming cultures accumulated considerable amounts of digitoxin (about 20 to 40 micrograms per gram dry weight), and the white, shoot-forming cultures without chloroplasts accumulated about one-third that amount of digitoxin. The chlorophyll content and the ribulose bisphosphate carboxylase activity of the undifferentiated green cells were about the same as they were in the green, shoot-forming cultures, but the digitoxin content of the former was extremely low (about 0.05 to 0.2 microgram per gram dry weight), which is about the same as that in undifferentiated white cells without chloroplasts. Thus, it was concluded that the chloroplasts are not essential for the synthesis of digitoxin in Digitalis cells. The optimum concentrations of the tested compounds for accumulation of digitoxin were: benzyladenine, 0.01 to 1 milligram per liter; indoleacetic acid, 0.1 to 1 milligram per liter; α-naphthaleneacetic acid; 0.1 milligram per liter; and 2,4-dichlorophenoxyacetic acid, 0.01 milligram per liter.     

Characterization of Growth, Water Relations, and Proline Accumulation in Sodium Sulfate Tolerant Callus of Brassica napus L. cv Westar (Canola)

Unselected and sodium sulfate tolerant callus cultures of Brassica napus L. cv Westar were grown on media supplemented with mannitol, NaCl, or Na₂SO₄. In all cases, growth of tolerant callus, measured on a fresh weight or dry weight basis, was greater than that of unselected callus, which was also subject to necrosis on high levels of salt. Tissue water potential became more negative in both unselected and tolerant callus grown in the presence of mannitol or Na₂SO₄. Water potentials in unselected callus were more negative than those of the tolerant tissues; but over a range of Na₂SO₄ concentrations both cultures displayed osmotic adjustment, maintaining relatively constant turgor. Proline accumulation in both unselected and tolerant callus was low (15 to 20 micromoles per gram dry weight) in the absence of stress, but increased on media supplemented with mannitol, NaCl, or Na₂SO₄. Increases in proline concentration were approximately linear in tolerant callus, reaching a maximum of 130 to 175 micromoles per gram dry weight. In unselected callus, concentrations were higher, reaching 390 to 520 micromoles per gram dry weight. Proline accumulation was correlated with inhibition of growth, and there was a negative correlation between proline concentration and culture age for tolerant callus.     

Growth Yields and Maintenance Coefficients of Unadapted and NaCl-Adapted Tobacco Cells Grown in Semicontinuous Culture

Comparison of carbon utilization between unadapted and NaCl (428 millimolar) adapted tobacco (Nicotiana tabacum L.) cells under substrate limited growth conditions was facilitated using semicontinuous culture. Growth yields (Y_g) and maintenance coefficients (m) of unadapted and NaCl adapted cells were similar, indicating that the efficiency of carbon utilization for growth was not altered as a result of salt adaptation and that no additional metabolic costs were associated with growth of adapted cells in the presence of a high concentration (428 millimolar) of NaCl. The Y_g (0.588 grams organic dry weight gain per gram sugar uptake) and m values (0.117 grams sugar uptake per gram organic dry weight per day) were comparable in spite of substantial physiological and biochemical differences that exist between unadapted and NaCl adapted cells. Apparently, a metabolic homeostasis governs biomass production of cells before and after adaptation to salinity.     

Dynamics of Endogenous Cytokinins during the Growth Cycle of a Hormone-Autotrophic Genetic Tumor Line of Tobacco

The profile of endogenous cytokinins in a genetic tumor line of tobacco, namely, Nicotiana glauca (Grah.) × Nicotiana langsdorffii (Weinm.), following 1 to 10 weeks of growth on solid medium was determined by radioimmunoassay. ³H-labeled cytokinins of high specific activity were added during tissue extraction to correct for the purification losses. Following subculture (of 4-week-old tissues when their cytokinin content is high) onto fresh medium the total cytokinin content continued to be high during the first week (1470 picomoles per gram fresh weight) when the tissue fresh weight remained essentially unchanged (lag phase). The cytokinin levels then declined by about half in 2- and 3-week-old tissues (626 and 675 picomoles per gram fresh weight, respectively), a period when rapid increase in tissue fresh weight was recorded. Increments of 840% and 2780% over initial fresh weight were obtained in 2- and 3-week-old cultures, respectively. The cytokinin content then increased to initial high levels in 4-week-old tissues (1384 picomoles per gram fresh weight) after which it gradually declined with tissue age. The lowest cytokinin levels (432 picomoles per gram fresh weight) were observed in 10-week-old tissues. Maximal tissue fresh weight (4030% increase over initial fresh weight) was recorded in 5-week-old cultures after which it decreased slowly to 77.5% of the highest tissue fresh weight in 10-week-old cultures. Zeatin appeared to be the dominant endogenous cytokinin in tissues of all ages. Other cytokinins quantified were dihydrozeatin, zeatin riboside, and dihydrozeatin riboside; the values may include contributions from aglucones derived from the hydrolysis of corresponding O-glucosides, since the entire basic fraction was treated with β-glucosidase before analysis. In addition the levels of isopentenyladenine, isopentenyladenosine, and the nucleotides of zeatin riboside, dihydrozeatin riboside, and isopentenyladenosine were also determined.     

Mixotrophic and heterotrophic growth of Beggiatoa alba in continuous culture

Beggiatoa alba strain B18LD was grown in continuous culture under heterotrophic conditions on acetate or acetate and asparagine and under mixotrophic conditions on acetate plus either 1 mM sodium sulfide or 1 mM sodium thiosulfate. Considerable differences were observed between the yields and the cell compositions of heterotrophic and mixotrophic cultures at all dilution rates tested. The dry weight yield per gram acetate utilized was approximately three times higher in the acetate-sulfide mixotrophic culture than in the acetate heterotrophic culture, whereas the poly--hydroxybutyric acid and carbohydrate contents were much higher in the heterotrophic cultures. The high yields (0.52–0.75, corrected for the weight of the sulfur) obtained with the mixotrophic cultures imply that the acetate was utilized mainly for biosynthesis. Thus, the oxidation of sulfide supplied energy. The addition of catalase to the chemostat cultures increased yields slightly, but it was insufficient to explain the differences between the heterotrophic and the mixotrophic cultures.     

Seasonal variation in the energy content of benthic macroinvertebrates of Lake Nainital,U.P., India

The paper discusses seasonal variation in the energy contents of four macrobenthic invertebrates of Lake Nainital during 1977–78. The energy values varied from 16971–19437 J/g dry weight in Tubifex tubifex, 16 511–20 231 J/g dry weight in Glossiphonia weberi, 19 019–25 289 J/g dry weight in Chironomus plumosus and 19 583–20 549 J/g dry weight in Viviparus bengalensis. The former two genera exhibited highest energy contents during summer, whereas the latter two revealed highest values during winter. On mean annual basis, the highest values were recorded for C. plumosus and lowest for T. tubifex. In V. bengalensis, variation occurred in ash fraction (%) and in energy values (Joule per gram dry weight) but not in energy values of organic fraction (Joule per gram ash-free dry weight), while the other three genera displayed variation in all three variables.     

Bioinsecticidal activity of conidia and dry mycelium preparations of two isolates of Beauveria bassiana against the sugarcane borer Diatraea saccharalis

Two isolates of Beauveria bassiana (Bb₁ and Bb₅ strains) were grown in solid-state and submerged cultures (SSC and SbC, respectively) in order to obtain conidia and dry mycelium preparations. The samples obtained at laboratory scale were tested as alternatives for their further use as mycoinsecticides to control the sugarcane borer Diatraea saccharalis. The spore yields obtained in SSC indicated that the Bb₅ strain was able to produce around three times more conidia per gram of initial dry matter (3.7×10¹⁰) than the Bb₁ strain (1.3×10¹⁰) in a solid medium composed of wheat bran and bran husk. Under this culture conditions, the former showed not only satisfactory spore yields, but also a higher bioinsecticidal activity than the latter. Laboratory bioassays carried out with conidia of both strains against D. saccharalis larvae indicated that the Bb₅ strain promotes an insect mortality of 82.5% whereas only 21.3% was observed with the Bb₁ strain preparations. Concerning the samples obtained in SbC, in which a culture medium based on glucose and yeast extract was employed, it is interesting to point out that although both strains showed similar behaviors with yields of approximately 1.50×10¹⁰ conidia per gram of dry mycelium, both preparations failed in their bioinsecticidal activities. Despite satisfactory yields, bioinsecticidal activity of the Bb₁ and Bb₅ strains dropped drastically showing a larvae mortality below 2%.     

Stimulation of Isopentenyl Pyrophosphate Incorporation into Polyisoprene in Extracts from Guayule Plants (Parthenium argentatum Gray) by Low Temperature and 2-(3,4-Dichlorophenoxy) Triethylamine

Rubber particles isolated from guayule (Parthenium argentatum Gray) stem homogenates contain a polyprenyl transferase which catalyzes the polymerization of isopentenyl pyrophosphate into polyisoprene. The polymerization reaction is stimulated with the addition of an allylic pyrophosphate initiator and forms a polymer of polyisoprene with a molecular weight distribution from 10³ to 10⁷. The polymerization reaction in crude stem homogenates is not affected by the addition of an initiator probably due to the high activity of isopentenyl pyrophosphate isomerase furnishing saturating levels of dimethylallyl pyrophosphate. Polyisoprene formation in stems of guayule plants exposed to cold winter temperatures increased from 15.4 milligrams per gram dry weight in October to 24.5 milligrams per gram dry weight in January and increased from 16.2 to 38.1 milligrams per gram dry weight in the same period by additionally treating the plants with 5000 ppm of 2-(3,4-dichlorophenoxy)triethylamine. The rate of polymerization of isopentenyl pyrophosphate into polyisoprene in stem homogenates of the cold treated plants increased from 12.1 nanomoles per hour per gram fresh weight in October to 144.3 nanomoles per hour per gram fresh weight in January and increased from 17.7 to 446.8 nanomoles per hour per gram fresh weight in the same period by additionally treating the plants with 5000 ppm of 2-(3,4-dichlorophenoxy)triethylamine. These results show that the increase in polyprenyl transferase activity partially accounts for the increase in polyisoprene synthesis in guayule plants exposed to low temperature and treated with 2-(3,4-dichlorophenoxy)triethylamine.     

Effects of cooling rate on seeds exposed to liquid nitrogen temperatures

The effect of cooling rate on seeds was studied by hydrating pea (Pisum sativum), soybean (Glycine max), and sunflower (Helianthus annuus) seeds to different levels and then cooling them to − 190°C at rates ranging from 1°C/minute to 700°C/minute. When seeds were moist enough to have freezable water (> 0.25 gram H₂O/gram dry weight), rapid cooling rates were optimal for maintaining seed vigor. If the seeds were cooled while at intermediate moisture levels (0.12 to 0.20 gram H₂O per gram dry weight), there appeared to be no effect of cooling rate on seedling vigor. When seeds were very dry (< 0.08 gram H₂O per gram dry weight), cooling rate had no effect on pea, but rapid cooling rates had a marked detrimental effect on soybean and sunflower germination. Glass transitions, detected by differential scanning calorimetry, were observed at all moisture contents in sunflower and soybean cotyledons that were cooled rapidly. In pea, glasses were detectable when cotyledons with high moisture levels were cooled rapidly. The nature of the glasses changed with moisture content. It is suggested that, at high moisture contents, glasses were formed in the aqueous phase, as well as the lipid phase if tissues had high oil contents, and this had beneficial effects on the survival of seeds at low temperatures. At low moisture contents, glasses were observed to form in the lipid phase, and this was associated with detrimental effects on seed viability.     

Carbohydrate Responsive Proteins in the Roots of Pennisetum americanum

The effect of changes in carbohydrate status on the synthesis of specific proteins was investigated in millet (Pennisetum americanum L., Leeke, Tift 23B₁E₁) seedlings grown in sterile solution culture. Carbohydrate status was altered by extended darkness and sucrose feeding. Root proteins from intact seedlings were labeled with [³⁵S]methionine, phenol-extracted, separated by two-dimensional gel electrophoresis, and visualized by autoradiography. In four separate experiments, two proteins showed a consistent change in labeling when root carbohydrate levels were varied between 200 and 1000 micromole hexose per gram residual dry weight. Labeling of the first protein (P₄₇, M_r 47 kD) increased as the carbohydrate levels rose above 500 micromole hexose per gram residual dry weight. Labeling of the second protein (P₃₄, M_r 34 kD) increased as carbohydrate levels declined from 500 to 200 micromole hexose per gram residual dry weight. Under extreme conditions, when carbohydrate levels fell below 100 micromole hexose per gram residual dry weight, the labeling pattern of most proteins was drastically altered. It is suggested that P₄₇ and P₃₄ are `carbohydrate responsive proteins,' i.e. proteins whose concentrations are controlled either directly or indirectly by tissue carbohydrate status. In contrast, the changes in protein labeling that occur once carbohydrate pools are depleted may be involved in adaptation to periods of prolonged starvation.     

Water Content during Abscisic Acid Induced Freezing Tolerance in Bromegrass Cells

Changes in water content and dry weight were determined in control cells and those induced to cold harden in response to abscisic acid (ABA) treatment (7.5 × 10⁻⁵ molar). Bromegrass (Bromus inermis Leyss cv Manchar) cells grown in suspension culture at room temperature (23°C) for 7 days acclimated to −28°C (LT₅₀) when treated with ABA, or to −5°C when untreated. ABA significantly reduced cell growth rates at 5 and 7 days after treatment. Growth reduction was due to a decrease in cell number rather than cell size. When the cell water content was expressed as percent water (percent H₂O) or as grams water per gram dry weight (gram H₂O/gram dry weight [g DW]), the water content of hardy, ABA-treated cells decreased from 85% to 77% or from 6.4 to 3.3 g H₂O/g DW in 7 days. Control cell water content remained static at approximately 87% and 7.5 g H₂O/g DW. However, cell water content, expressed as milligrams water per million cells (milligram H₂O/10⁶ cells), did not differ in ABA-treated or control cells. The dry matter content of ABA-treated cells, expressed as milligram DW/10⁶ cells increased to 3.3 milligram/10⁶ cells in 7 days, whereas the dry weight of the control cells remained between 1.4 to 2.1 milligrams/10⁶ cells. The osmotic potential of ABA-treated cells decreased by the fifth day while that of control cells increased significantly and then decreased by day 7. Elevated osmotic potentials were not associated with increased ion uptake. In contrast to much published literature, these results suggest that cell water content does not decrease in ABA-treated cells during the induction of freezing tolerance, rather the dry matter mass per cell increased. Cell water content may be more accurately expressed as a function of cell number when accompanying changes to dry cell matter occur.     

Bound Water in Durum Wheat under Drought Stress

To study drought stress effects on bound water, adsorption isotherms and pressure-volume curves were constructed for two durum wheat (Triticum durum Desf.) cultivars: Capeiti 8 (drought tolerant) and Creso (drought sensitive). Plants were grown under well-watered and water-stressed conditions in a controlled environment. Differential enthalpy (ΔH) was calculated through van't Hoff analysis of adsorption isotherms at 5 and 20°C, which allowed us to determine the strength of water binding. ΔH reached the most negative values at approximately 0.06 gram H₂O/gram dry weight and then increased rapidly for well-watered plants (until 0.10 gram H₂O/gram dry weight) or more slowly for drought-stressed plants (until 0.15-0.20 gram H₂O/gram dry weight). Bound water values from pressure-volume curves were greater for water-stressed (0.17 gram H₂O/gram dry weight) than for well-watered plants (0.09 gram H₂O/gram dry weight). They may be estimates of leaf moisture content where ΔH reaches the less negative values and hence some free water appears. With respect to the well-watered plants, tightly bound water tended to be less bound during drought, and more free water was observed in cv Creso compared to cv Capeiti 8 at moisture contents >0.10 gram H₂O/gram dry weight.     

Sucrose Phosphate Synthase, Sucrose Synthase, and Invertase Activities in Developing Fruit of Lycopersicon esculentum Mill. and the Sucrose Accumulating Lycopersicon hirsutum Humb. and Bonpl

The green-fruited Lycopersicon hirsutum Humb. and Bonpl. accumulated sucrose to concentrations of about 118 micromoles per gram fresh weight during the final stages of development. In comparison, Lycopersicon esculentum Mill. cultivars contained less than 15 micromoles per gram fresh weight of sucrose at the ripe stage. Glucose and fructose levels remained relatively constant throughout development in L. hirsutum at 22 to 50 micromoles per gram fresh weight each. Starch content was low even at early stages of development, and declined further with development. Soluble acid invertase (EC 3.2. 1.26) activity declined concomitant with the rise in sucrose content. Acid invertase activity, which was solubilized in 1 molar NaCl (presumably cell-wall bound), remained constant throughout development (about 3 micromoles of reducing sugars (per gram fresh weight) per hour. Sucrose phosphate synthase (EC 2.4.1.14) activity was present at about 5 micromoles of sucrose (per gram fresh weight) per hour even at early stages of development, and increased sharply to about 40 micromoles of sucrose (per gram fresh weight) per hour at the final stages of development studied, parallel to the rise in sucrose content. In comparison, sucrose phosphate synthase activity in L. esculentum remained low throughout development. The possible roles of the sucrose metabolizing enzymes in determining sucrose accumulation are discussed.     

A Transformation-induced Alteration of Cellular Membranes in Crown Gall Tumor Cells

Phospholipids were utilized as a membrane marker to test for transformation-induced alteration of cellular membranes of cultured crown gall cells of Vinca rosea L. Fully transformed cells contained less than half the amount of phospholipids (7.8 micrograms lipid P per gram fresh weight) of normal V. rosea cells (21.4 micrograms lipid P per gram fresh weight). The normal V. rosea callus cells were not significantly different (P > 0.05) in phospholipid content from partially transformed crown gall cells (20.7 micrograms lipid P per gram fresh weight). Stimulation to rapid growth of the partially transformed cells by adding higher concentrations of inorganic salts and auxin did not significantly alter their phospholipid content (23.1 micrograms lipid P per gram fresh weight). These findings suggest that the transformation process is directly responsible for an alteration of the cellular membranes and that the membrane alteration cannot be attributed to secondary effects associated with the rapid growth of these neoplastic cells.     

Comparative Study of Metals Accumulation in Cultured In Vitro Mycelium and Naturally Grown Fruiting Bodies of Boletus badius and Cantharellus cibarius

Cantharellus cibarius Fr. (chanterelle) and Boletus badius Pers. (bay bolete) harvested from natural sites in Poland were used to derive in vitro cultures. The optimal medium composition for cultures was developed. Concentrations of the chosen elements (Zn, Cu, Fe, Mg, Ni, and Cd) in mycelium samples were measured by means of atomic absorption spectrometry. Fe concentration in the analyzed mushroom materials was in the range 215.4–680.3 μg/g dry weight. Mean values of Mg were respectively (in micrograms per gram dry weight) 541.8 for mycelium of C. cibarius cultured in vitro and 1,004.1 for C. cibarius fruiting bodies and 928.9 for the mycelium of B. badius cultured in vitro and 906.4 for B. badius fruiting bodies. The mean concentrations of Zn were 442.7 μg/g dry weight in mycelium from in vitro cultures of B. badius and 172.1 in B. badius fruiting bodies and 131.9 in the case of C. cibarius in mycelium from in vitro cultures and 95.5 for the C. cibarius fruiting bodies. Cu exhibited a reversal tendency, i.e., the element concentrations in naturally grown mushrooms were significantly higher (43.57 μg/g dry weight for C. cibarius and 43.54 μg/g for B. badius) than in cultured in vitro mycelium (12.47 μg/g for C. cibarius and 4.17 μg/g for B. badius). Ni was found in lowest concentrations ranging from 0.33 to 1.88 μg/g dry weight. Toxic metal Cd was found in relatively high concentrations in naturally grown species (0.79 μg/g dry weight—1.02). The lowest was the concentration of Cd in C. cibarius mycelium from in vitro culture—0.06 μg/g dry weight—a bit higher than it was in the B. badius mycelium (0.21 μg/g).     

Extraction efficiency,phytochemical profiles and antioxidative properties of different parts of Saptarangi (Salacia chinensis L.) – An important underutilized plant

The study aimed to evaluate extraction efficiency, detection and quantification of phytochemicals, minerals and antioxidative capacity of different parts of Salacia chinensis L. Continuous shaking extraction, steam bath assisted extraction, ultrasonic extraction and microwave assisted extraction with varied time intervals were employed for extraction of phenolics, flavonoids, and antioxidants. Preliminary screening revealed the presence of wide array of metabolites along with carbohydrates and starch. Steam bath assisted extraction for 10 min exposure was found most suitable for extraction phenolics (46.02 ± 2.30 mg of gallic acid equivalent per gram of dry weight and 48.57 ± 2.42 mg of tannic acid equivalent per gram of dry weight) and flavonoids (35.26 ± 1.61 mg of quercetin equivalent per gram of dry weight and 51.60 ± 2.58 mg of ellagic acid equivalent per gram of dry weight). In support, reverse phase-high performance liquid chromatography- diode array detector confirmed the presence of seven pharmaceutically important phenolic acids. Antioxidant capacity was measured by 1, 1- diphenyl-1-picryl hydrazyl (DPPH), ferric reducing antioxidant power (FRAP), 2, 2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) scavenging (ABTS) and N, N-dimethyl-p-phenylenediamine (DMPD) assays and represented as trolox equivalent antioxidant capacity (TEAC) and ascorbic acid equivalent antioxidant capacity (AEAC). Antioxidant capacity ranged from 121.02 ± 6.05 to 1567.28 ± 78.36 µM trolox equivalent antioxidant capacity and 56.62 ± 2.83 to 972.48 ± 48.62 µM ascorbic acid equivalent antioxidant capacity. Roots showed higher yields of illustrated biochemical parameters, however fresh fruit pulp was found a chief source of minerals. Gas chromatography-mass spectroscopic analysis revealed the presence of a vast array of phytoconstituents associated with different plant parts. The present study revealed the amounts of minerals and diverse phytoconstituents in various parts of S. chinensis and confirmed its medicinal and nutritional implications.     

Maturation in Larch : II. Effects of Age on Photosynthesis and Gene Expression in Developing Foliage

The effect of maturation on the morphological and photosynthetic characteristics, as well as the expression of two genes involved in photosynthesis in the developing, current year foliage of Eastern larch (Larix laricina [Du Roi]) is described. These effects were observed on foliage during the third growing season after grafting of scions from trees of different ages onto 2 year old rootstock. Specific leaf weight (gram dry weight per square meter), leaf cross-sectional area (per square millimeter), and chlorophyll content (milligram per gram dry weight) all increase with increasing age in long shoot foliage from both indoor- and outdoor-grown trees. Net photosynthesis (NPS) (mole of CO₂ per square millimeter per second) increases with age on indoor- but not outdoor-grown trees. NPS also increases with increased chlorophyll content, but outdoor-grown scions of all ages had higher chlorophyll content, and chlorophyll does not appear to be limiting for NPS outdoors. To extend these studies of maturation-related differences in foliar morphology and physiology to the molecular genetic level, sequences were cloned from the cab and rbsS gene families of larch. Both cab and rbcS gene families are expressed in foliage but not in roots, and they are expressed in light-grown seedlings of larch but only at very low levels in dark-grown seedlings (~2% of light-grown seedlings). Steady-state cab mRNA levels are relatively higher (~40%) in newly expanding short shoot foliage from juvenile plants compared to mature plants. Unlike cab, the expression of the rbcS gene family did not seem to vary with age. These data show that the maturation-related changes in morphological and physiological phenotypes are associated with changes in gene expression. No causal relationship has been established, however. Indeed, we conclude that the faster growth of juvenile scions reported previously (MS Greenwood, CA Hopper, KW Hutchison [1989] Plant Physiol 90: 406-412) is not due to increased NPS or cab expression. Long shoot foliage is the dominant foliar type on young trees and its lower specific leaf weight will permit production of more photosynthetic surface area per unit of leaf biomass.     

Comparison of Proanthocyanidins and Related Compounds in Leaves and Leaf-Derived Cell Cultures of Ginkgo bioloba L., Pseudotsuga menziesii Franco, and Ribes sanguineum Pursh

Proanthocyanidins, flavan-3-ols, and their flavanoid precursors in leaves and leaf-derived callus and cell suspension cultures have been isolated and analyzed by high performance liquid chromatography with C₁₈ columns, paper chromatography, and by chemical and spectrophotometric methods. Cultures of Ginkgo biloba and Pseudotsuga menziesii (Douglas-fir) produced much greater amounts of proanthocyanidins than leaves per milligram dry weight. In cultures, however, the prodelphinidin component relative to that of procyanidins decreased; this was most pronounced in Pseudotsuga. In contrast, callus cultures of Ribes sanguineum accumulated proanthocyanidins in amounts about equal to those in intact leaves per milligram dry weight and the prodelphinidin content remained high. Although Ginkgo and Ribes leaves contained major amounts of flavan-3-ols and dimers with the 2,3-cis-stereochemistry, their cultures tended to synthesize 2,3-trans-isomers instead. Glycosides of flavanone and 3-hydroxyflavanone precursors accumulated in medium to high amounts on a dry weight basis in leaves and cultures of Ribes and Pseudotsuga, and the 3′-glycosidic linkage predominated when the latter species was cultured with 2,4-dichlorophenoxyacetic acid rather than naphthaleneacetic acid.     

Buoyant Densities and Dry-Matter Contents of Microorganisms: Conversion of a Measured Biovolume into Biomass

Several isolates of bacteria and fungi from soil, together with cells released directly from soil, were studied with respect to buoyant density and dry weight. The specific volume (cubic centimeters per gram) of wet cells as measured in density gradients of colloidal silica was correlated with the percent dry weight of the cells and found to be in general agreement with calculations based on the partial specific volume of major cell components. The buoyant density of pure bacterial cultures ranged from 1.035 to 1.093 g/cm³, and their dry-matter content ranged from 12 to 33% (wt/wt). Average values proposed for the conversion of bacterial biovolume into biomass dry weight are 1.09 g/cm³ and 30% dry matter. Fungal hyphae had buoyant densities ranging from 1.08 to 1.11 g/cm³, and their dry-matter content ranged from 18 to 25% (wt/wt). Average values proposed for the conversion of hyphal biovolume into biomass dry weight are 1.09 g/cm³ and 21% dry matter. Three of the bacterial isolates were found to have cell capsules. The calculated buoyant density and percent dry weight of these capsules varied from 1.029 g/cm³ and 7% dry weight to 1.084 g/cm³ and 44% dry weight. The majority of the fungi were found to produce large amounts of extracellular material when grown in liquid cultures. This material was not produced when the fungi were grown on either sterile spruce needles or membrane filters on an agar surface. Fungal hyphae in litter were shown to be free from extracellular materials.     

Carbon Partitioning in Soybean Infected with Meloidogyne incognita and M. javanica

Seven-day-old seedlings of two cultivars (Cristalina and UFV ITM1) of Glycine max were inoculated with 0, 3,000, 9,000, or 27,000 eggs of Meloidogyne incognita race 3 or M. javanica and maintained in a greenhouse. Thirty days later, plants were exposed to ¹⁴CO₂ for 4 hours. Twenty hours after ¹⁴CO₂ exposure, the root fresh weight, leaf dry weight, nematode eggs per gram of root, total and specific radioactivity of carbohydrates in roots, and root carbohydrate content were evaluated. Meloidogyne javanica produced more eggs than M. incognita on both varieties. A general increase in root weight and a decrease in leaf weight with increased inoculum levels were observed. Gall tissue appeared to account for most of the root mass increase in seedlings infected with M. javanica. For both nematodes there was an increase of total radioactivity in the root system with increased levels of nematodes, and this was positively related to the number of eggs per gram fresh weight and to the root fresh weight, but negatively related to leaf dry weight. In most cases, specific radioactivities of sucrose and reducing sugars were also increased with increased inoculum levels. Highest specific radioactivities were observed with reducing sugars. Although significant changes were not observed in endogenous levels of carbohydrates, sucrose content was higher than reducing sugars. The data show that nematodes are strong metabolic sinks and significantly change the carbon distribution pattern in infected soybean plants. Carbon partitioning in plants infected with nematodes may vary with the nematode genotype.