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PubMed1970

Mobilization and Incorporation of Photoassimilated C by Growing Vegetative and Reproductive Tissues of Adult Pinus resinosa Ait. Trees.

Variations in translocation and incorporation of (14)C-labeled photosynthate in actively growing vegetative and reproductive tissues of 20-year-old Pinus resinosa trees with time were investigated. Five hours after exposure of 1-year-old needles on second order branches to (14)CO(2), 90% of the recoverable activity was still in the needles. The 1-year-old bark showed a small amount of activity, but terminal sinks had accumulated little (14)C. After 24 hours, activity in the 1-year-old needles decreased to 59% while actively growing terminal and lateral shoots and 2nd year cones had accumulated considerable tracer. Whereas activity in the 1-year-old bark increased, recovery from the 1-year-old wood was only 1.8%. After 1 week, relative activity in the 1-year-old needles had declined to 27%. Recovery of (14)C from various sinks was high and in the following order: 2nd year cones > terminal needles > lateral needles > terminal internode > lateral internodes > 1-year-old wood. Ninety per cent of the (14)C recovered after 5 hours was in the ethanol-soluble form, but by the end of 1 week only half was in the soluble fraction. Incorporation of tracer into insoluble compounds was high in expanding internodes and in 1-year-old xylem, and low in 2nd year cones. Total activity in the terminal internode generally declined toward the distal end while specific radioactivity increased. Only 5% of the (14)C recovered from cones was localized in developing seeds, but specific radioactivity of seeds was higher than in the cone scales and axis.

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PubMed1973

The Effects of Octanoate and Oleate on Isocitrate Lyase Activity during the Germination of Pinus pinea Seeds.

The changes of isocitrate lyase levels with respect to the catabolism of triglycerides have been studied during the germination of Pinus pinea seeds. We studied the effects of octanoate, oleate, and inhibitors of protein synthesis on isocitrate lyase during germination. Pyruvate kinase, glucose-6-P-dehydrogenase, malate dehydrogenase, and isocitrate dehydrogenase were also assayed. Octanoate and oleate inhibited the isocitrate lyase activity, similarly to cycloheximide, chloramphenicol, and actinomycin, inhibitors of protein biosynthesis. This inhibitory effect is not specific but is strikingly evident with isocitrate lyase. This inhibition was not proportional to the concentration but was proportional to the chain length of oleate and octanoate.

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PubMed1975

Endogenous Gibberellins of Pine Pollen: II. Changes during Germination of Pinus attenuata, P. coulteri, and P. ponderosa Pollen.

The endogenous gibberellins (GAs) of pollen of Pinus attenuata, P. coulteri, and P. ponderosa were bioassayed at hour 0, 3, 15, 24, 48 and 72 of germination. Dormant pollen showed relatively high GA activity throughout the elution spectrum (i.e. ranging from relatively nonpolar to highly polar). The maximum GA activity was obtained at hour 15 in more polar regions and especially in the zone corresponding to GA(3) (for P. attenuata estimated as 250 micrograms of GA(3)/kilogram pollen). It is probable that the "nonpolar" GAs present in high quantities in dormant pollen and in early stages of germination were converted to "more polar" GAs as germination progressed. The amount of all GAs decreased after hour 15 of germination and by hour 72 no GAs could be detected. Among the species tested P. attenuata showed the highest over-all GA activity.

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PubMed1975

Red-Far Red Reversible Effect on Polysome Formation in the Embryos of Pinus thunbergii Seeds.

Polysome formation in the embryos of Pinus thunbergii seeds was studied. Free ribosomes were dissociated to smaller subunits in a high salt buffer, but the complex ribosomes were not. The free ribosomes could be distinguished from monomer ribosomes derived from polysomes after RNase treatment. The monomer ribosomes present in the embryos of the dark-imbibed seeds were predominantly free ribosomes; very small quantities of polysomes could be detected in the embryos from dark-imbibed seeds. Such polysomes remained at a very low level during dark imbibition at least for a month. The level of polysomes increased 4 hours after a brief exposure to red light. The effect of red light on polysome formation was partially reversed when followed by far red light irradiation.

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PubMed1976

Endogenous Gibberellins of Pine Pollen: III. Conversion of 1,2-[H]GA(4) to Gibberellins A(1) and A(34) in Germinating Pollen of Pinus attenuata Lemm.

Gibberellins A(1) and A(34) (possibly A(2)) were found as products of metabolism of 1,2-[(3)H]GA(4) during germination of Pinus attenuata pollen. The conversion from GA(4) to GA(1) and GA(34) occurred as hydroxylations at atoms C-13 and C-2 of the ent-gibberellane skeleton, respectively. Percentage interconversion of the GA(4) absorbed was in the range of 0.15 to 0.43% for GA(1) and 1.54 to 3.22% for GA(34). Identifications were made on a gas-liquid chromatograph with radioactive monitoring by comparison with standards.

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PubMed1978

Influence of the Irradiance on Carbohydrate Content and Rooting of Cuttings of Pine Seedlings (Pinus sylvestris L.).

Seedlings of Pinus sylvestris L. were grown for 6 weeks at an irradiance of either 8 or 40 watts per square meter in a controlled environment room. Cuttings from these plants were rooted in tap water for 75 days at either 8 or 40 watts per square meter. The photoperiod was 17 hours.During the first 30 days of the rooting period quantitative changes in carbohydrates were recorded in cuttings from the different treatments. The carbohydrate contents of the cuttings were mainly regulated by the irradiance during the stock plant stage and generally a higher carbohydrate level was found in cuttings from stock plants grown at 40 watts per square meter.The irradiance during the rooting period had only minor effects on the time course of root formation, whereas the irradiance during the stock plant stage did influence the subsequent root formation. Cuttings from stock plants grown at 8 watts per square meter rooted faster and with higher frequency than those from stock plants grown at 40 watts per square meter. These results are discussed in relation to the mentioned irradiance effects on carbohydrate content.

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PubMed1979

Cadmium Uptake by Pinus resinosa Ait. Pollen and the Effect on Cation Release and Membrane Permeability.

Cadmium uptake by red pine (Pinus resinosa Ait.) pollen from a graded series of Cd(2+) solutions (0 to 2.88 microequivalents per 50 milligrams pollen) and its effect on membrane integrity were examined by atomic absorption spectroscopy. Uptake was strongly dependent on Cd(2+) concentration and was limited to adsorption and cation exchange in pollen walls during a 3-hour measurement period. Good correlation between measured Cd(2+) uptake and that predicted by the Langmuir and Freundlich isotherm equations indicated the adsorptive nature of Cd(2+) uptake. While substantial quantities of Ca(2+) and Mg(2+) were released by exchange mechanisms concurrent with Cd(2+) uptake, there was no evidence for leakage of cations due to membrane impairment as indicated by a poor correlation between Cd(2+) uptake and K(+) efflux. Virtually all Cd(2+) removed from solution was freely exchangeable with 0.5 millimolar CaCl(2) and demonstrated that Cd(2+) did not readily enter pine pollen but was adsorbed on the pollen wall. Ultraviolet transmission spectra of treatment solutions and analyses of phosphate and reducing sugar efflux also indicated that the potent toxicity of Cd(2+) to pollen germination and germ tube elongation was not the result of membrane damage.

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PubMed1979

Thymidylate synthase activity from chlamydomonas cells and cultured tissues of Nicotiana, pinus, and daucus.

Prior preparation of N(5),N(10)-methylenetetrahydrofolate from dl-tetrahydrofolate and [(14)C]formaldehyde resulted in an improved assay for thymidylate synthase. Although preparations from tobacco seedlings and cotton root tips (0.25 centimeter) were inconsistent with respect to enzyme activity, extracts from actively growing cell cultures of Chlamydomonas, Nicotiana hybrid callus, Pinus callus, and Daucus proembryonic cells contained significant levels of thymidylate synthase (12.3 to 23.8 nanomoles of thymidylate formed per milligram of protein per hour).

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PubMed1980

Soil Temperature Influences on Root Resistance of Pinus contorta Seedlings.

The influence of low temperature in the root zone on water uptake in lodgepole pine (Pinus contorta Dougl. ex Loud.) was studied under laboratory conditions. To remove soil hydraulic influences, two-year-old seedlings were transferred to solution cultures and maintained in temperature controlled water baths. Short term measurements of leaf conductance, leaf water potential and tritiated water movement were taken at root temperatures from 22 C down to 0 C. Root resistance was calculated to be 67% of total plant resistance at 7 C and 93% at 0 C. In addition an Arrhenius break was found in a plant resistance versus temperature plot, suggesting a significant change with temperature in the membrane pathway in the root water uptake system.

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PubMed1980

On the Reason for the Different Photosynthetic Rates of Seedlings of Pinus silvestris and Betula verrucosa.

The growth and net photosynthetic properties of seedlings of Pinus silvestris L. and Betula verrucosa Ehrh., grown under identical conditions in a controlled environment chamber, were compared. The relative growth rate of birch was about twice that of pine. The rates of in situ net photosynthesis were 1.50 and 2.30 micromoles CO(2) meter(-2) second(-1) and the photosynthetic quantum yields under light-limiting conditions were 0.022 and 0.032 for pine and birch, respectively. The total leaf surface areas were used for calculating the CO(2) flux densities. The difference in the rates of in situ net photosynthesis depended equally on morphological and metabolic factors. It was assumed that a pronounced mutual shading and an unfavorable leaf inclination made the pine seedlings less efficient in absorbing the unidirectional light of the climate chamber than the broadleaved seedlings of birch. Both pine and birch were adapted to the growth conditions so the flux densities of absorbed quanta were rate-limiting for in situ net photosynthesis. It was concluded that the difference in the photosynthetic quantum yields (i.e. the linear slope of the photosynthetic light curve) of the two species defined the metabolically controlled part of the difference in the rate of in situ net photosynthesis. The quantum yield of pine was lower than that of birch and was partly explained by pine having a higher rate of photorespiration than birch. The remaining difference was most likely controlled by the properties of the chloroplast thylakoids, e.g. energy transfer efficiency between pigments, photosynthetic electron transport, or coupling between electron transport and photophosphorylation.

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PubMed1982

Seasonally Induced Changes in Acyl Lipids and Fatty Acids of Chloroplast Thylakoids of Pinus silvestris: A CORRELATION BETWEEN THE LEVEL OF UNSATURATION OF MONOGALACTOSYLDIGLYCERIDE AND THE RATE OF ELECTRON TRANSPORT.

Current-year needles were sampled regularly from an approximately 20-year-old natural stand of Pinus silvestris. Chloroplast thylakoids were isolated. The electron transport capacities of photosystem II + photosystem I, as well as of the partial photoreactions, were measured. The amounts and the fatty acid compositions of monogalactosyldiglyceride, digalactosyldiglyceride, and sulfolipid of the thylakoids were analyzed. The fatty acid composition of the phospholipids (total) was also determined.There was a 2-fold increase in the content of the galactolipids and the sulfolipid in the thylakoid preparations during the autumn. Except for monogalactosyldiglyceride that decreased in content during early winter, the content of the other two lipids remained high during the winter, until spring when their content fell toward a low summer level. The ratio of monogalactosyldiglyceride to digalactosyldiglyceride was lower in thylakoids isolated from frosthardened (autumn, winter) than in those isolated from unhardened (summer) needles.Only monogalactosyldiglyceride showed pronounced and significant seasonal variations in the molar ratio of unsaturated to saturated fatty acids. It was low in the winter, and it increased strongly during the spring. The highest ratio was observed in September, prior to the first night frosts, after which a steady decrease toward the low winter value occurred. This decrease is thought to be a reflection of membrane damages (photooxidation of membrane components, including polyunsaturated fatty acids), as earlier seen reflected in chlorophyll destruction, electron transport inhibition, and structural changes.There was very good correlation between the seasonal variations in the capacity for electron transport from water to NADP and the level of unsaturation of monogalactosyldiglyceride (r = 0.93). It has been shown earlier that the winter inhibition of electron transport preferentially occurs at the lipophilic electron transport carrier plastoquinone and that the free miscibility of plastoquinone and monogalactosyldiglyceride is prevented in saturated monogalactosyldiglyceride. Therefore, it is hypothesized that the decreased level of unsaturation of monogalactosyldiglyceride reduces the mobility of plastoquinone in the thylakoids, resulting in an inhibition of the electron transport by way of plastoquinone.

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PubMed1983

Gas Chromatography-Mass Spectroscopy Identification of 1-Aminocyclopropane-1-carboxylic Acid in Compressionwood Vascular Cambium of Pinus contorta Dougl.

Following cation and anion exchange chromatography, 1-aminocyclopropane-1-carboxylic acid (ACC) was converted to the 2,4-dinitrophenyl derivative and then purified by high-performance liquid chromatography (HPLC). After three HPLC steps, endogenous ACC was identified by GCMS in the vascular cambium on the lower side of Pinus contorta Dougl. ssp. latifolia branches in association with compressionwood differentiation, but ACC was not detected in the opposite wood cambial region on the upper sides of the same branches.The possibility that ACC and ethylene have physiological roles in cambial activity and compressionwood tracheid differentiation is discussed.

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PubMed1983

Computer-Assisted Image Analysis of Tissues of Ethrel-Treated Pinus taeda Seedlings.

A microcomputer based video image analyzer is described and demonstrated in the analysis and comparison of tissue types of 6-month-old Ethrel-treated and control seedlings of loblolly pine (Pinus taeda L.). Two different programs were employed. ;Topographer I' sought, identified, and measured cell or resin canal lumen areas, and ;Area' measured tracheid length and silhouette areas. Ethrel treatment induced an increase in radial growth and a decrease in shoot elongation and needle growth. Bark production was stimulated by the same treatment. The tracheid lumens of Ethrel-treated plants were shorter and had a smaller cross-sectional area, whereas the tracheid cell walls increased in thickness. The treatment also increased resin canal formation in the xylem.

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PubMed1983

Cold Acclimation of Suspension Cultures of Pinus sylvestris in Response to Light and Temperature Treatments.

Suspension cultures of Pinus sylvestris L. (Provenance Södra Ydre) were used to determine frost hardiness after manipulating daylengths and temperatures. Frost hardiness was determined with the triphenyltetrazolium chloride (TTC) reduction method. The cultures were able to acclimate and increase frost hardiness levels; both low temperature (2 degrees C) and short day (8 h) treatments were used at the same time, but increased survival temperatures were not achieved when only one type of stimulus was used. Inasmuch as intact seedlings can be partially acclimated by a single type of stimulus, the results indicate that the organization of the cells to tissues plays a role for the hardening process in vivo.

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PubMed1984

Changes in Cytokinins and Gibberellin-Like Substances in Pinus radiata Buds during Lateral Shoot Initiation and the Characterization of Ribosyl Zeatin and a Novel Ribosyl Zeatin Glycoside.

Based on detection and quantitation by bioassay, endogenous gibberellin-like substances (GAs) and cytokinins (CKs) in Pinus radiata D. Don buds during sequential shoot initiation shift from less polar to more polar forms (GAs) and from conjugated to free forms (CKs). As the terminal bud moves from the production of "short shoots" (needle fascicles) to "long shoots" (lateral branches or female conebuds), a more polar GA appears while a glucoside-conjugate of zeatin riboside is reduced, and zeatin riboside levels increase markedly.Permethyl derivatives of the two highly active CK fractions were examined by capillary gas chromatography-mass spectrometry after separation by C(18) reverse phase high performance liquid chromatography. The mass spectra indicated the presence of: 9-beta-d-ribofuranosyl-6-(4-hydroxy-3-methyl-but-2-enylamino)purine (zeatin riboside) and 9-[hexosyl(probably glucosyl)-beta-d-ribofuranosyl]-6-(4-hydroxy-3-methyl-but-2- enylamino)purine (a glycoside of zeatin riboside in which the glycosyl moiety is attached directly to the ribosyl moiety at an unknown position).

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PubMed1984

Factors Affecting the Emission of Monoterpenes from Red Pine (Pinus densiflora).

The mechanism of monoterpene emission from Pinus densiflora was studied using an environmentally controlled gas cabinet. It was found that monoterpene emission rate increases exponentially with temperature and is also influenced by light. These observations were explained reasonably by a mechanism whereby monoterpene emission rate depends on the monoterpene amount in the leaf oil and its saturated vapor pressure.

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PubMed1984

Gibberellin A(4/7) and the Promotion of Flowering in Pinus radiata: Effects on Partitioning of Photoassimilate within the Bud during Primordia Diferentiation.

Gibberellin A(4/7) mixture (GA(4/7)), a highly effective promoter of early and enhanced flowering in the Pinaceae, caused a significant reallocation of dry matter and (14)C-photosynthate within terminal buds of Pinus radiata D. Don within 8 days of hormone treatment. Treatment with GA(4/7) to terminal shoots of vigorous, potentially flowering mature grafted propagules reduced the flow of photoassimilated (14)C and dry matter into the terminal bud as a whole, but significantly increased the dry matter and (14)C allocated within the bud to developing long-shoot primordia (potential seed-cone buds). This was accomplished at the expense of the structural tissues, the apical dome region, and the vegetative branch buds. Although GA(3) caused a similar reallocation of dry matter within the terminal bud, it was significantly less effective than GA(4/7) thus appears to have, in addition to any nutrient diversion abilities, a distinct morphogenic function in sexual differentiation.

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PubMed1985

Identification and Quantification of Indole-3-methanol in Etiolated Seedlings of Scots Pine (Pinus sylvestris L.).

Combined gas chromatography-mass spectrometry has been used to identify indole-3-methanol in a purified buffer extract from etiolated seedlings of Pinus sylvestris L. Quantitative estimates obtained by high performance liquid chromatography with fluorescence detection, corrected for losses occurring during purification, indicated that etiolated seedlings of P. sylvestris contained 19.7 +/- 1.4 nanograms (+/- standard deviation) indole-3-methanol per gram fresh weight. The stability of indole-3-methanol at different pH levels was investigated. The rate of conversion, to a less polar unidentified substance, was enhanced with increasing acidity.

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