Browsing by Author "Prehn, D"

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    Isolation of Pinus radiata genomic DNA suitable for RAPD analysis
    (1998) Stange, C; Prehn, D; Arce-Johnson, P
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    Optimization of in vitro culture conditions for Pinus radiata embryos and histological characterization of regenerated shoots
    (1999) Stange, C; Prehn, D; Gebauer, M; Arce-Johnson, P
    Different in vitro culture conditions were tested on Pinus radiata organogenic embryos. Optimum shoot induction occurred at 26.1 degrees C, whereas the best elongation resulted at 21.4 degrees C. Supplements of 2.5 mg/l or 5 mg/l of BAP added to the induction media produced a similar number of regenerated shoots, which differed statistically from 1.0 mg/l of BAP and 0.025 mg/l TDZ. Addition of 10 mg/l MnSO4 to LP1/2 medium significantly increased the number and quality of in vitro regenerated shoots. The removal the apical region of shoots cultured in LP 2.5 mg/l of BAP increased the number of de novo generated shoots by 23%, compared to a control group with intact shoots. Approximately 70% of the in vitro shoots of P. radiata were of wet phenotype (hyperhydrated appearance); the rest were waxy in appearance. Histological cuts did not produce any differences in phenotypes, but scanning electronic microscopy of needles gave evidence of differences in epicuticular wax deposits. Abbreviations: LP: Quoirin and LePoivre basal medium, without plant growth regulators; LP,: LP medium + 1 mg/l BAP; LP2.5: LP medium+ 2.5 mg/l BAP; LP5 : LP medium + 5 mg/l BAP; LP1/2: LP basal medium at half strength of macroelements, 2%; commercial sugar, ammonium nitrate 100 mg/l, calcium nitrate 564.5 mg/l, hydroxyquinoleine 1.25 mg/l, MS vitamins and without plant growth regulators; LPT0.025: LP medium + 0.025 mg/l TDZ; BAP: N-6 benzylaminopurine; TDZ: Thidiazuron.
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    Regeneration of whole plants from apical meristems of Pinus radiata
    (2003) Prehn, D; Serrano, C; Mercado, A; Stange, C; Barrales, L; Arce-Johnson, P
    A methodology to regenerate whole plants of Pinus radiata from apical meristems of 3- and 7-year-old trees was developed. Meristematic domes with two or three leaf primordia were excised from surface-sterilized branch tips of field-grown plants and cultured in LP medium with half strength macronutrients (1/2 LP) and full strength micronutrients. The early growth of meristems required approximately 12 weeks, including a recovery stage during the first 2 weeks. After 8 weeks, some meristems developed abnormal phenotypes and died during the subsequent stages of development. However, healthy meristems elongated and formed shoots when they were transferred to LP medium supplemented with MS vitamins, 30 mg l(-1) casein hydrolysate, and 0.4 g l(-1) agar plus 2.85 g l(-1) Gelrite. Meristems that developed vigorous shoots were used for rooting experiments when they were 2 cm in length. Whole plants were obtained after 5 days of root induction in water-agar medium containing 8.2 muM IBA and 5.4 muM NAA and 1 month culture in LP medium with 10 g l(-1) sucrose. Plants regenerated from meristems were further propagated by rooting of cuttings. Of the rooted cuttings, 10% were morphologically juvenile.