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Variation in the polysome assembly and incorporation of [3H]-uridine in the cells of pine buds during the cold season (1985)

Häggman, Hely ; Hohtola, Anja ; Kupila-Ahvenniemi, Sirkka

Oxford, UK : Blackwell Publishing Ltd

Physiologia plantarum 65 (1985), S. 0

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ISSN: 1399-3054

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology

Notes: The ribosome assemblies isolated from buds of Scots pine (Pinus sylvestris L.) containing microsporangiate strobili varied both quantitatively and qualitatively in samples collected from October to April. The seasonal fluctuation in the amount of ribosonnes was more evident in the cytosolic fraction than in the smaller membrane-bound fraction. The profiles obtained after sucrose density gradient centrifugation were of two types. One type was commonly obtained from samples collected late in the autumn and early in the spring, and this type was characterized by a relatively high peak for the large subunits, a low or negligible peak for the dimers, and an even or ascending series of peaks for the polymers. The other type was obtained from samples collected during the winter, and was characterized by small peaks for both subunits, a moderate to large peak for the dimers and a descending series of peaks for the polymers. However, the scanning electron microscope investigations indicated that the winter-time samples did not lack polysomes and clusters of ribosomes. They did not become visible in the polysome profiles because they pelleted too tightly at the bottom of the centrifuge tubes to be removed with gradient fractionation. The au-toradiographic analyses suggested that the cells were capable of synthesizing mRNA throughout the winter, whereas rRNA synthesis was arrested. On the basis of the above results, we postulate that the synthesis of the enzyme proteins needed for the maintenance of winter-time metabolism takes place in the cytosolic ribosome fraction. The possible existence of winter-time polysome stores is also pointed out.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1111/j.1399-3054.1985.tb08665.x

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Tissue browning of in vitro cultures of Scots pine: Role of peroxidase and polyphenol oxidase (1999)

Laukkanen, Hanna ; Häggman, Hely ; Kontunen-Soppela, Sari ; [et al.]

Copenhagen : Munksgaard International Publishers

Physiologia plantarum 106 (1999), S. 0

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ISSN: 1399-3054

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology

Notes: Callus cultures from shoot tips of mature Scots pine (Pinus sylvestris L.) were characterized by rapid browning and an inability to regenerate. The peroxidase (POD) and polyphenol oxidase (PPO) activities and relationship to browning in such cultures were compared with embryogenic and non-embryogenic cultures of Scots pine, started from immature embryos of three different pine clones. The browning in callus cultures derived from pine buds was visible approximately after 2 weeks of culture, and continued thereafter until the callus was dark brown and poorly growing. The non-embryogenic cultures induced from immature embryos showed either light yellow coloring or browning, whereas the embryogenic cultures showed browning. POD activity increased during the first 4 weeks in callus tissue initiated from pine buds, and was significantly higher than in pine buds or cultures derived from immature embryos. The ability of cultures initiated from pine buds to oxidize catechol was notably high compared with cultures initiated from immature embryos, regardless of the time of measurement. Addition of catalase revealed that both POD and PPO were able to use catechol as substrate. An antibody raised against broad bean (Vicia faba) chloroplast PPO was used to recognize PPO. One polypeptide with a molecular mass of 50 kDa was detected in all pine samples on SDS-PAGE and non-denaturing PAGE. Another polypeptide with a molecular mass of 70 kDa was shown exclusively in the light-yellow non-embryogenic cultures. The results suggest that especially the high POD activities in callus tissues started from mature trees cause rapid and early browning and possibly subsequent cell death.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1034/j.1399-3054.1999.106312.x

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3

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Bud endophytes of Scots pine produce adenine derivatives and other compounds that affect morphology and mitigate browning of callus cultures (2004)

Pirttilä, Anna Maria ; Joensuu, Päivi ; Pospiech, Helmut ; [et al.]

Oxford, UK; Malden, USA : Munksgaard International Publishers

Physiologia plantarum 121 (2004), S. 0

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ISSN: 1399-3054

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology

Notes: Endophytes are found in meristematic bud tissues of Scots pine (Pinus sylvestris L.) especially prior to growth, which would suggest their involvement in growth of the bud. To test this hypothesis, production of phytohormones by two bacterial (Methylobacterium extorquens, Pseudomonas synxantha) and one fungal endophyte (Rhodotorula minuta) was studied by mass spectrometry. The most common gibberellins, auxins, or cytokinins were not detected in the fractions studied. Instead, M. extorquens and R. minuta produced adenine derivatives that may be used as precursors in cytokinin biosynthesis. A plant tissue culture medium was conditioned with the endophytes, and pine tissue cultures were started on the media. Tetracycline inhibited callus production, which was restored on the endophyte-conditioned media. In addition, conditioning mitigated browning of the Scots pine explants. However, a decrease in tissue size was observed on the endophyte-conditioned media. Addition of adenosine monophosphate in the plant culture medium restored callus production and increased growth of the tissues, but had no effect on browning. Therefore, production of adenine ribosides by endophytes may play some role in the morphological effect observed in the pine tissues.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1111/j.0031-9317.2004.00330.x

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4

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Effect of different nitrogen nutrients on the viability, protein synthesis and tannin production of Scots pine callus (1997)

Laukkanen, Hanna ; Julkunen-Tiitto, Riitta ; Hohtola, Anja

Oxford, UK : Blackwell Publishing Ltd

Physiologia plantarum 100 (1997), S. 0

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ISSN: 1399-3054

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology

Notes: The effect of two different media on the growth, metabolism and viability of Scots pine (Pinus sylvestris) callus cultures was studied. Inorganic nitrogen in the culture media (modified MS) was in the form of either KNO3 or NH4NO3. The cultures were started from buds of mature Scots pine. Growth was poor on the medium with KNO3, but this compound had a noticeable effect on the metabolism of the callus, which was reflected in alterations in protein and polyphenol synthesis and the pH of the culture medium. Although the fresh mass, water content and viability of the callus decreased when KNO3 was the exclusive inorganic nitrogen nutrient, protein synthesis was more abundant. Electrophoretic analyses indicated alterations in the patterns of soluble proteins and purified glycoproteins. Phenylalanine ammonia-lyase (EC 4.3.1.5) activities were high in all the calluses, and concentrations of condensed tannins and their precursors, catechins, were higher than in intact buds. The role of inorganic nitrogen nutrition in the deterioration of tissues is discussed on the basis of the effect of ammonium on the metabolism of pine callus.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1111/j.1399-3054.1997.tb00026.x

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5

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Structure of the nucleoli of developing microsporangiate strobili and root tips of scotch pine (1979)

Kupila-Ahvenniemi, Sirkka ; Hohtola, Anja

Springer

Protoplasma 100 (1979), S. 289-301

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ISSN: 1615-6102

Keywords: Nucleolus structure ; Pinus ; Root tip ; Strobilus

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Summary The characteristics of the nucleoli of the microsporangiate strobili and the root tips of Scotch pine (Pinus sylvestris L.) vary both during the course of the cellular cycle and, with regard to the pattern and stage of organ and tissue differentiation. Nucleologenesis takes place in interphase and the nucleoli last until prophase. Several types of nucleoli occur during the nucleolar cycle, the pattern and age of tissues determining which type or types dominate. In the strobilus primordia collected at the end of July and in August, the mitotic frequency is high. Nucleoli remain small throughout the nucleolar cycle, and at the electron microscopic level, they display intermingled fibrillar and fibrillogranular components. Strobilus primordia collected in September contain larger nucleoli in the sporogenous nuclei than in the nuclei of the tapetum or of the wall cells. Amongst the nucleoli with completely intermingled fibrous and granular material, nucleoli with nucleolonema or with vacuoles occur frequently. Small balls of fibrous material are seen on the nucleolar surface and in the nucleoplasm. In October, the mitotic frequency of strobilal cells is low. Nucleoli with completely intermingled fibrillar and granular components have vanished whereas a new, compact type of nucleolus with a dense fibrillogranular main portion and with nucleolonema, has developed. The nucleoli of the sporogenous cells have enlarged continuously whereas those of the wall cells are small. The nucleoli of the root tip cell resemble, to a certain extent, those of the strobilus primordia collected in September. In squashed preparations, the nucleoli of the strobilal cells bind the common nucleolar stains poorly whereas the nucleoli of the root cells can be stained with all the methods used. In certain cases, DNase treatment improves the stainability of the strobilal nucleoli. AgNO3-staining is successful after acetic acid: alcohol fixation but not after formalin: hydrochinone fixation.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF01279317

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6

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Nucleoli of the overwintering strobilal cells of scotch pine (1980)

Kupila-Ahvenniemi, Sirkka ; Hohtola, Anja

Springer

Protoplasma 105 (1980), S. 107-119

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ISSN: 1615-6102

Keywords: Dormancy ; Nucleolus ; Nucleolus organizer ; Pinus

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Summary Monthly collections from October to April revealed seasonal alterations in the structure of the nucleoli of the microsporangiate strobili of the Scotch pine (Pinus sylvestris L.). By classifying the nucleoli in five types, two of them with subtypes, it was possible to list the amount and the sequence of the changes. The results indicated that nucleoli with fully intermingled fibrillar and granular components dominated in actively proliferating tissues whereas this type was almost lacking during the so-called dormant period. The wintertime nuclei, although remaining at interphases, also underwent structural alterations. In the early part of the winter, the most prominent feature was the loosening of the nucleolar structure, but this phenomenon decreased towards midwinter. The chromatin became strongly condensed and synchronous with this, the nucleolar organizer regions became visible as distinct, often ball-like entities. These were located at the surface of nucleoli, sometimes almost separated from them, and they were often partly, or fully, buried in condensed chromatin. Chromatin condensation relaxed transiently during the latter part of winter and at the same time, the granulation of the nucleoplasm increased. Nucleolar segregation disappeared before any mitoses began. The start of active cell divisions was accompanied by growth in the size of the nucleoli and by their increased stainability.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF01279853

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7

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Seasonal changes in explant viability and contamination of tissue cultures from mature Scots pine (1988)

Hohtola, Anja

Springer

Plant cell, tissue and organ culture 15 (1988), S. 211-222

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ISSN: 1573-5044

Keywords: Pinus sylvestris L. ; shoot tip culture ; callus proliferation ; browning

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract Explants from 10 to 40-year-old Scots pine trees (Pinus sylvestris L.) were cultured in vitro. Material was collected from Northern Finland once or twice a week during 1984–1987. excised shoot meristems and lower parts of the buds formed soft callus on modified MS medium. A seasonal effect was observed in the explant viability and degree of contamination. Callus proliferation was highest from explants collected in December and January and during the growing season from April to July, and lowest in February and during the autumn from September to November. It seemed that the bud metabolism at each particular time was rather persistent and affected the outcome of the experiments. Contamination was significantly higher from December to April. Organogenesis occurred only rarely.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00033645

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8

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Freeze-preservation of buds from Scots pine trees (1991)

Kuoksa, Tero ; Hohtola, Anja

Springer

Plant cell, tissue and organ culture 27 (1991), S. 89-93

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ISSN: 1573-5044

Keywords: cryopreservation ; Pinus sylvestris L. ; tissue culture

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract A procedure has been developed for freeze-preservation of buds of the Scots pine (Pinus sylvestris L.). Instead of liquid nitrogen, cold storage in −80°C was used. The partly dormant material used in the experiments was obtained directly from a natural stand in Northern Finland and no prefreezing or cryoprotectants for preconditioning were used. Cooling velocity was 1°C/min up to a terminal freezing temperature of −39°C, after which the buds were immersed in liquid nitrogen at −196°C for 10 minutes. The material was then transferred to a deepfreezer at −80°C and stored up to 6 months. After rapid thawing, the buds were sterilized and their viability was tested by FDA staining and by culturing meristems on 1/2 MS medium for at least two weeks. All the freezing experiments were performed during March and April. The best survival of buds (90–100%) was achieved at the beginning of April, after which a pronounced decline in survival occurred obviously due to a rise in the water content of the buds.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00048212

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